Florida pompano

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Florida pompano | Trachinotus carolinus

Florida pompano info via Wikipedia:

Florida pompano
Pompano common.jpg
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Carangidae
Genus: Trachinotus
Species: T. carolinus
Binomial name
Trachinotus carolinus
(Linnaeus, 1766)

The Florida pompano (Trachinotus carolinus[2]) is a species of marine fish in the Trachinotus (pompano) genus of the family Carangidae. It has a compressed body and short snout; coloration varies from blue-greenish silver on the dorsal areas and silver to yellow on the body and fins. It can be found along the western coast of the Atlantic Ocean, depending on the season, and is popular for both sport and commercial fishing. Most Florida pompano caught weigh less than 3 lb (1.4 kg) and are less than 17 in (43 cm) long, though the largest individuals weigh 8–9 lb (3.6–4.1 kg) and reach lengths up to 26 in (66 cm).

Because it is fast-growing and desirable for food, the pompano is one of the many fish that is currently being farmed through aquaculture.

The Florida city of Pompano Beach is named after the Florida pompano.

Description

The different kinds of pompano include African, Cayenne, Florida and Irish. The Florida pompano (T. carolinus) is part of the jack family. It is very similar to the permit (Trachinotus falcatus). It has a deeply forked tail and is blue-greenish silver with yellow on the throat, belly, and pelvic and anal fins. The first dorsal fins are low, with about six separate spines. The first spine may be reabsorbed in a larger fish. The second lobes on the dorsal and anal fins have a lower anterior.[3] There are 20-24 anal fin rays. It is a compressed fish with a deep body and a blunt snout.

Trachinotus carolinus, Rio Grande do Sul, Brazil

Size

Pompano WL.png

Juvenile pompano grow between 0.8 and 1.9 in (20 and 48 mm) per month, depending on the population. Pompano grow quickly and attain a length of about 12 in (30 cm) and a weight of about 1 lb (0.45 kg) after the first year. The relationship between total length (L, in inches) and total weight (W, in pounds) for nearly all fish can be expressed by an equation of the form: W = c L b {\displaystyle W=cL^{b}\!\,} W=cL^{b}\!\,

Invariably, b is close to 3.0 for all species, and c is a constant that varies among species.[4] A weight-length relationship was determined for a sample of 1,984 Florida pompano collected along the Gulf Coast of Florida between 2000 and 2002.[5] The fish sampled ranged in length from 79–481 mm (3.16-19.24 in). For this sample of Florida pompano, b = 2.9342 and c = 0.00076.

This relationship predicts that a 12-inch (300 mm) pompano will weigh about a pound. Most are less than three pounds when caught, though the largest pompano recorded have weighed 8-9 lb and were 23-25 in long.

Lifespan

The Florida pompano usually survives for only about three to four years,[6] although individuals as old as 6-7 yr have been caught.[5]

Range and habitat

The adult Florida pompano is typically found in more saline areas and relatively warm waters (70-89 °F), so it migrates northward in the summer, and toward the south in the fall.[6] Despite its name, the range of the Florida pompano extends from Massachusetts to Brazil, but it is more common in areas near Florida. During the summer, it can be found near Sebastian, Cape Hatteras, and the Gulf of Mexico. It is more common near oil rigs, Palm Beach, and Hobe Sound during the winter. It can also be found near the Virgin Islands year round.

Its habitat is surf flats, and it tends to stay away from clear water regions, such as the Bahamas.[7] Pompanos are very fast swimmers and live in schools. They are bottom feeders. They have very short teeth and feed on zoobenthos and small clams.

Ecology

Food

The pompano is a popular food fish. Chefs like it because the fillets are of even thickness, which aids in cooking. A popular dish created in New Orleans, called “pompano en papillote,” is wrapped in parchment paper with a white sauce of wine, shrimp, and crabmeat, and then steamed.[8]

The pompano’s flesh is oily and looks white and opaque. Its diet yields a rich but mild flavor. Fresh fillets can cost $17 or more.[9] Demand has encouraged the use of aquaculture to increase supply.

Aquaculture

The Florida pompano is a popular choice for aquaculture because it is such a popular food and sport fish and is in high demand, and at the same time it has a fast growth rate, high dockside prices,[10] and a tolerance for low-salinity waters.[10] The typical market size of farm-raised pompano is 1 to 1.5 lb (0.45 to 0.68 kg).[11]


Fishing

The pompano supports an important commercial and recreational fishery. Florida pompano are commercially fished in all states on the East Coast from Virginia to Texas, with Florida producing over 90% of the annual harvest. Harvesting occurs mostly along Florida's western coast, with some harvesting on the eastern coast and in the Banana and Indian Rivers. Between 1994 and 2006, it commanded dockside prices of more than $3 per pound of whole fish weight.[11]

Individually, Florida pompano are caught on light jigs and popping corks. They are very active on the line, testing light tackle beyond what their weight would suggest.[8] They bite near oil rigs in the winter.

From 1997-2000, the fishing mortality rates increased sharply. However, an extensive study by the Florida Fish and Wildlife Conservation Commission concluded, as of 2005, the population of Florida pompano was healthy and the fishery was sustainable with current practices.[5][8]

References

  1. ^ Smith-Vaniz, W.F.; Williams, J.T.; Pina Amargos, F.; Curtis, M.; Brown, J. (2015). "Trachinotus carolinus". The IUCN Red List of Threatened Species. IUCN. 2015: e.T16507646A16510412. doi:10.2305/IUCN.UK.2015-4.RLTS.T16507646A16510412.en. Retrieved 10 August 2017. 
  2. ^ Froese, Rainer and Pauly, Daniel, eds. (2006). "Trachinotus carolinus" in FishBase. April 2006 version.
  3. ^ Smith, C. Lavett, National Audubon Society Field Guide to Tropical Marine Fishes of the Caribbean, the Gulf of Mexico, Florida, the Bahamas, and Bermuda. Chanticleer Press, 1997, ISBN 0-679-44601-X, color plate 268, p. 490
  4. ^ R. O. Anderson and R. M. Neumann, Length, Weight, and Associated Structural Indices, in Fisheries Techniques, second edition, B.E. Murphy and D.W. Willis, eds., American Fisheries Society, 1996.
  5. ^ a b c Murphy, M.D., Muller, R.G., Guindon, K. A stock assessment for pompano, Trachinotus carolinus, in Florida waters through 2005. Report to the Florida Fish and Wildlife Conservation Commission, Division of Marine Fisheries Management. In-house report 2008-004, 2008.
  6. ^ a b ESPN page on Florida pompano Archived 2006-05-27 at the Wayback Machine.
  7. ^ Smithsonian Marine Station page on Florida pompano
  8. ^ a b c Ristori, Al. The Saltwater Fish Identifier. New York: Mallard Press, 1992, ISBN 0-7924-5575-4, pp. 44
  9. ^ "Archived copy". Archived from the original on 2010-04-13. Retrieved 2010-06-12. 
  10. ^ a b rch%20and%20Development MOTE Marine Laboratory aquaculture of Florida pompano
  11. ^ a b Southern Regional Aquacultural Center (Texas A&M) Species Profile on Florida pompano 2007[permanent dead link]
source: http://en.wikipedia.org/wiki/Florida_pompano

Bull Shark Skull

92W_Carcharhinus_leucas_vers1_24x20

 

Bull Shark | Carcharhinus leucas

Bull Shark info via Wikipedia:

Bull shark
Bullshark Beqa Fiji 2007.jpg
Carcharhinus leucas TPWD.jpg
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Carcharhiniformes
Family: Carcharhinidae
Genus: Carcharhinus
Species: C. leucas
Binomial name
Carcharhinus leucas
(J. P. Müller and Henle, 1839)
Cypron-Range Carcharhinus leucas.svg
Range of bull shark

The bull shark (Carcharhinus leucas), also known as the Zambezi shark or, unofficially, as Zambi in Africa and Lake Nicaragua shark in Nicaragua, is a requiem shark commonly found worldwide in warm, shallow waters along coasts and in rivers. The bull shark is known for its aggressive nature, predilection for warm shallow water, and presence in brackish and freshwater systems including estuaries and rivers.

Bull sharks can thrive in both salt and fresh water and can travel far up rivers. They have been known to travel up the Mississippi River as far as Alton, Illinois,[2] although few freshwater human-shark interactions have been recorded. Larger sized bull sharks are probably responsible for the majority of near-shore shark attacks, including many bites attributed to other species.[3]

Unlike the river sharks of the genus Glyphis, bull sharks are not true freshwater sharks, despite their ability to survive in freshwater habitats.

Etymology

The name "bull shark" comes from the shark's stocky shape, broad, flat snout, and aggressive, unpredictable behavior.[4] In India, the bull shark may be confused with the Sundarbans or Ganges shark. In Africa, it is also commonly called the Zambezi River shark or just Zambi. Its wide range and diverse habitats result in many other local names, including Ganges River shark, Fitzroy Creek whaler, van Rooyen's shark, Lake Nicaragua shark,[5] river shark, freshwater whaler, estuary whaler, Swan River whaler,[6] cub shark, and shovelnose shark.[7]

Evolution

Some of the bull shark's closest living relatives do not have the capabilities of osmoregulation. Its genus, Carcharhinus, also includes the sandbar shark, which is not capable of osmoregulation.[8]

The bull shark shares numerous similarities with river sharks of the genus Glyphis, and other species in the genus Carcharhinus, but its phylogeny has not been cleared yet.[9]

Anatomy and appearance

Bull sharks are large and stout, with females being larger than males. The bull shark can be up to 81 cm (2.66 ft) in length at birth.[10] Adult female bull sharks average 2.4 m (7.9 ft) long and typically weigh 130 kg (290 lb), whereas the slightly smaller adult male averages 2.25 m (7.4 ft) and 95 kg (209 lb). While a maximum size of 3.5 m (11 ft) is commonly reported, a single record exists of a female specimen of exactly 4.0 m (13.1 ft). The maximum recorded weight of a bull shark was 315 kg (694 lb), but may be larger.[3][11][12] Bull sharks are wider and heavier than other requiem sharks of comparable length, and are grey on top and white below. The second dorsal fin is smaller than the first. The bull shark's caudal fin is longer and lower than that of the larger sharks, and it has a small snout, and lacks an interdorsal ridge.[10]

Bull sharks have a bite force up to 5,914 newtons (1,330 lbf), weight for weight the highest among all investigated cartilaginous fishes.[13]

Distribution and habitat

The bull shark is commonly found worldwide in coastal areas of warm oceans, in rivers and lakes, and occasionally salt and freshwater streams if they are deep enough. It is found to a depth of 150 m (490 ft), but does not usually swim deeper than 30 m (98 ft).[14] In the Atlantic, it is found from Massachusetts to southern Brazil, and from Morocco to Angola. In the Indian Ocean, it is found from South Africa to Kenya, India, Vietnam, Philippines to Australia.[citation needed]

Populations of bull sharks are also found in several major rivers, with more than 500 bull sharks thought to be living in the Brisbane River. One was reportedly seen swimming the flooded streets of Brisbane, Queensland, Australia, during the 2010-11 Queensland floods.[15] Several were sighted in one of the main streets of Goodna, Queensland, shortly after the peak of the January 2011, floods.[16] A large bull shark was caught in the canals of Scarborough, just north of Brisbane within Moreton Bay. Still greater numbers are in the canals of the Gold Coast, Queensland.[17] In the Pacific Ocean, it can be found from Baja California to Ecuador. The bull shark has traveled 4,000 km (2,500 mi) up the Amazon River to Iquitos in Peru[18] and north Bolivia.[1] It also lives in freshwater Lake Nicaragua, in the Ganges and Brahmaputra Rivers of West Bengal, and Assam in Eastern India and adjoining Bangladesh.[citation needed] It can live in water with a high salt content as in St. Lucia Estuary in South Africa. Bull sharks have been recorded in the Tigris River since at least 1924 as far upriver as Baghdad.[19] The bull shark is generally prolific in the warm, coastal waters and estuarine systems of the Mozambique Channel and southward, including Kwa-Zulu Natal and Mozambique.[citation needed] The species has a distinct preference for warm currents.[citation needed]

After Hurricane Katrina, many bull sharks were sighted in Lake Pontchartrain.[20] Bull sharks have occasionally gone up the Mississippi River as far upstream as Alton, Illinois,[21] and up the Ohio River as far as Manchester, Ohio.[22] They have also been found in the Potomac River in Maryland.[23][24] A golf course lake at Carbook, Logan City, Queensland, Australia is the home to several bull sharks. They were trapped following a flood of the Logan and Albert Rivers in 1996.[25] The golf course has capitalized on the novelty and now hosts a monthly tournament called the "Shark Lake Challenge".[26]

Behavior

Freshwater tolerance

The bull shark is the best known of 43 species of elasmobranch in 10 genera and four families to have been reported in fresh water.[27] Other species that enter rivers include the stingrays (Dasyatidae, Potamotrygonidae and others) and sawfish (Pristidae). Some skates (Rajidae), smooth dogfishes (Triakidae), and sandbar sharks (Carcharhinus plumbeus) regularly enter estuaries.[citation needed]

The bull shark is diadromous, meaning they can swim between salt and fresh water with ease.[28] These fish also are euryhaline fish, able to adapt to a wide range of salinities. The bull shark is one of the few cartilaginous fishes that have been reported in freshwater systems. Many of the euryhaline fish are bony fish such as salmon and tilapia and are not closely related to bull sharks. Evolutionary assumptions can be made to help explain this sort of evolutionary disconnect, one being that the bull shark encountered a population bottleneck that occurred during the last ice age.[29] This bottleneck may have separated the bull shark from the rest of the Elasmobranchii subclass and favored the genes for an osmoregulatory system.

Elasmobranchs' ability to enter fresh water is limited because their blood is normally at least as salty (in terms of osmotic strength) as seawater through the accumulation of urea and trimethylamine oxide, but bull sharks living in fresh water show a significantly reduced concentration of urea within their blood.[30] Despite this, the solute composition (i.e. osmolarity) of a bull shark in fresh water is still much higher than that of the external environment. This results in a large influx of water across the gills due to osmosis and loss of sodium and chloride from the shark's body. However, bull sharks in fresh water possess several organs with which to maintain appropriate salt and water balance; these are the rectal gland, kidneys, liver, and gills. All elasmobranchs have a rectal gland which functions in the excretion of excess salts accumulated as a consequence of living in seawater. Bull sharks in freshwater environments decrease the salt-excretory activity of the rectal gland, thereby conserving sodium and chloride.[31] The kidneys produce large amounts of dilute urine, but also play an important role in the active reabsorption of solutes into the blood.[31] The gills of bull sharks are likely to be involved in the uptake of sodium and chloride from the surrounding fresh water,[32] whereas urea is produced in the liver as required with changes in environmental salinity.[33] Recent work also shows that the differences in density of fresh water to that of marine waters result in significantly greater negative buoyancies in sharks occupying fresh water, resulting in increasing costs of living in fresh water. Bull sharks caught in freshwater have subsequently been shown to have lower liver densities than sharks living in marine waters. This may reduce the added cost of greater negative buoyancy.[34]

Bull sharks are able to regulate themselves to live in either fresh or salt water. It can live in fresh water for its entire life, but this does not happen, mostly due to reproduction. Young bull sharks leave the brackish water in which they are born and move out into the sea to breed. While theoretically, bull sharks to live in purely fresh water may be possible, the bull sharks that were being experimented on had died within four years. The stomach was opened and all that was found were two small, unidentifiable fishes. The cause of death could have been starvation since the primary food source for bull sharks resides in salt water.[35]

In a research experiment, the bull sharks were found to be at the mouth of an estuary for the majority of the time.[28] They stayed at the mouth of the river independent of the salinity of the water. The driving factor for a bull shark to be in fresh or salt water, however, is its age; as the bull shark ages, its tolerance for very low or high salinity increases.[28] The majority of the newborn or very young bull sharks were found in the freshwater area, whereas the much older bull sharks were found to be in the saltwater areas, as they had developed a much better tolerance for the salinity.[28] Reproduction is one of the reasons why adult bull sharks travel into the river—it is thought to be a physiological strategy to improve juvenile survival and a way to increase overall fitness of bull sharks.[28] The young are not born with a high tolerance for high salinity, so they are born in fresh water and stay there until they are able to travel out.

Initially, scientists thought the sharks in Lake Nicaragua belonged to an endemic species, the Lake Nicaragua shark (Carcharhinus nicaraguensis). In 1961, following specimen comparisons, taxonomists synonymized them.[36] They can jump along the rapids of the San Juan River (which connects Lake Nicaragua and the Caribbean Sea), almost like salmon.[14] Bull sharks tagged inside the lake have later been caught in the open ocean (and vice versa), with some taking as few as seven to 11 days to complete the journey.[36]

Diet

The bull shark's diet consists mainly of bony fish and small sharks, including other bull sharks,[3] but can also include turtles, birds, dolphins, terrestrial mammals, crustaceans, echinoderms, and stingrays. They hunt in murky waters where it is harder for the prey to see the shark coming.[1][37][38] Bull sharks have been known to use the bump-and-bite technique to attack their prey. After the first initial contact, they continue to bite and tackle prey until they are unable to flee.[39]

The bull shark is known to be a solitary hunter, although brief moments exist in which the bull shark teams up with another bull shark to make hunting and to tricking prey easier.[40][41]

Sharks are known to be opportunistic feeders,[39] and the bull shark is no exception to this, as it is part of the Carcharhinus family of sharks. Normally, sharks eat in short bursts, and when food is scarce, sharks digest for a much longer period of time in order to avoid starvation.[39] As part of their survival mechanism, bull sharks will regurgitate the food in their stomachs in order to escape from a predator. This is a distraction tactic; if the predator moves to eat the regurgitated food the bull shark can use the opportunity to escape.[42]

Reproduction

Bull sharks mate during late summer and early autumn,[8] often in freshwater[43] or in the brackish water of river mouths. After gestating for 12 months, a bull shark may give birth to 1 to 13 live young.[8][44]

They are viviparous, born live and free-swimming. The young are about 70 cm (27.6 in) at birth. The bull shark does not rear its young; the young bull sharks are born into flat, protected areas.[44] Coastal lagoons, river mouths, and other low-salinity estuaries are common nursery habitats.[3]

The male bull shark is able to begin reproducing around the age of 15 years while the female cannot begin reproducing until the age of 18 years.[44] The size of a fully matured female bull shark to produce viable eggs for fertilization seems to be 175 cm to 235 cm. The courting routine between bull sharks has not been observed in detail as of yet. The male likely bites the female on the tail until she can turn upside down and the male can copulate at that point. At some points, the harassment of the male can become violent. Seeing scratches and other marks on a mature female which may be from the mating ritual is not uncommon.[45]

Bull sharks have an unusual migratory pattern in comparison to other sharks. They are found in rivers all over the world. They give birth in the fresh water of rivers. The young bull sharks are free from predators while they grow up in the river before they go out to the sea to find mates.[46]

The ability to be able to survive in both fresh and salt water also gives another benefit that has been driven by evolution. Because the majority of sharks are only able to survive in salt water, the bull shark has evolved to have their offspring in the fresh water where other sharks cannot enter.[47] The freshwater acts as a protective area where the young are able to grow and mature without the threat of larger sharks preying on the younger bull sharks.[47] This is an explanation for the behavior that is observed from the Bull sharks as to why there would be any reason for the adult bull shark to ever travel into a freshwater area despite being able to tolerate the high salinity of marine water.

Interactions with humans

Photo of bull shark in shallow water
Bull shark (Bahamas)

Since bull sharks often dwell in very shallow waters, are found in many types of habitats, are territorial by nature and have virtually no tolerance for provocation, they may be more dangerous to humans than any other species of shark,[14] and along with the Tiger shark and great white shark, are among the three shark species most likely to bite humans.[4]

One or several bull sharks may have been responsible for the Jersey Shore shark attacks of 1916, which were the inspiration for Peter Benchley's novel Jaws.[48] The speculation of bull sharks possibly being responsible is based on two fatal bites occurring in brackish and fresh water.

The bull shark is responsible for biting swimmers around the Sydney Harbour inlets.[49] Most of these bites were previously attributed to Great White sharks. In India, bull sharks swim up the Ganges River and have bitten bathers. Many of these bite incidents were attributed to the Ganges shark, Glyphis gangeticus, a critically endangered river shark species, although the Sand Tiger shark was also blamed during the 1960s and 1970s.

The bull shark prefers coastal water which is less than 100 feet in depth. This is mostly due to their feeding patterns, since they prefer murky waters. This is also a problem since this gives the most interaction with humans. It is known that bull sharks inhabit areas off the coast of Florida, and there have been reports of bull sharks getting close enough to the coast to bite humans since the bull shark is a territorial animal, which encourages aggressive behavior.[50]

Visual cues

Behavioral studies have confirmed that sharks can take visual cues in order to discriminate between different objects.[46] The bull shark is able to discriminate between colors of mesh netting that is present underwater.[46] It was found that bull sharks tended to avoid mesh netting of bright colors rather than colors that blended in with the water. Bright yellow mesh netting was found to be easily avoided when it was placed in the path of the bull shark. This was found to be the reason that sharks are attracted to bright yellow survival gear rather than ones that were painted black.[46] This is very important because it gives an insight into how bull sharks are able to pick up certain visual keys underwater that might give them an advantage when seeking out certain prey.

Energy conservation

In 2008, researchers tagged and recorded the movements of young bull sharks in the Caloosahatchee River estuary. Specifically, they were testing to find out what determined the movement of the young bull sharks.[51] It was found that the young bull sharks synchronously moved downriver when the environmental conditions changed.[51] This large movement of young bull sharks were found to be moving as a response rather than other external factors such as predators. An interesting find was that the movement was directly related to the bull shark conserving energy for itself. One way the bull shark is able to conserve energy is that when the tidal flow changes, the bull shark uses the tidal flow in order to conserve energy as it moves downriver.[51] Another way for the bull shark to conserve energy is to decrease the amount of energy needed to osmoregulate the surrounding environment.[51]

Ecology

Bull sharks are apex predators and seldom have to fear being attacked by other animals. Humans are their biggest threat. Larger sharks, such as the tiger shark and great white shark, may attack them.[3] Crocodiles may be a threat to bull sharks in rivers. Saltwater crocodiles have been observed preying on bull sharks in the rivers and estuaries of Northern Australia,[52] and a Nile crocodile was reported as consuming a bull shark in South Africa.[53]

References

  1. ^ a b c Simpfendorfer, C. & Burgess, G.H. (2005). "Carcharhinus leucas". IUCN Red List of Threatened Species. Version 2011.1. International Union for Conservation of Nature. Retrieved 18 August 2011. 
  2. ^ Sharks In Illinois. In-Fisherman (16 July 2012). Retrieved on 30 November 2013.
  3. ^ a b c d e "Bull shark". Florida Museum of Natural History. Retrieved 8 September 2006. 
  4. ^ a b "Bull shark". National Geographic. Retrieved 3 April 2011. 
  5. ^ "Biology of Sharks and Rays". ReefQuest Centre for Shark Research. Retrieved 19 August 2010. 
  6. ^ McGrouther, Mark (12 May 2010). "Bull Shark, Carcharhinus leucas Valenciennes, 1839 – Australian Museum". Australian Museum. Retrieved 19 August 2010. 
  7. ^ Allen, Thomas B. (1999). The Shark Almanac. New York: The Lyons Press. ISBN 1-55821-582-4. 
  8. ^ a b c McAuley, R. B.; Simpfendorfer, C. A.; Hyndes, G. A. & Lenanton, R. C. J. (2007). "Distribution and reproductive biology of the sandbar shark, Carcharhinus plumbeus (Nardo), in Western Australian waters". Marine and Freshwater Research. 58 (1): 116–126. doi:10.1071/MF05234. The proportion of mature males with running spermatozoa increased from 7.1% in October to 79 and 80% in January and March, respectively, suggesting that mating activity peaks during late summer and early autumn. 
  9. ^ Fowler, S.; Reed, T.; Dipper, F. (1997). Elasmobranch biodiversity, conservation, and management: Proceedings of the international seminar and workshop. Gland Switzerland: IUCN. 
  10. ^ a b "Shark Species; Bull Sharks". Shark Diver Magazine. 17: 34. 2003. 
  11. ^ "The Biggest Bull Shark…Ever?". The Rosenstiel School of Marine & Atmospheric Science. 2012-07-18. 
  12. ^ "9 Biggest Sharks Ever Caught". Total Pro Sports.com. 
  13. ^ Habegger, M. L.; Motta, P. J.; Huber, D. R.; Dean, M. N. (2012). "Feeding biomechanics and theoretical calculations of bite force in bull sharks (Carcharhinus leucas) during ontogeny". Zoology. 115 (6): 354–364. doi:10.1016/j.zool.2012.04.007. ; for a popular summary, see Walker, Matt (12 October 2012). "Bull sharks have strongest bite of all shark species". BBC News. Retrieved 12 October 2012. 
  14. ^ a b c Crist, Rick. "Carcharhinus leucas". University of Michigan Museum of Zoology, Animal Diversity Web. Retrieved 8 September 2006. 
  15. ^ "Queensland rebuilding 'huge task'". BBC News. 12 January 2011. 
  16. ^ Bull sharks seen in flooded streets | Offbeat | Weird News, Odd and Freaky Stories in Northern Rivers | Clarence Valley Daily Examiner. Dailyexaminer.com.au (14 January 2011). Retrieved on 4 May 2012.
  17. ^ Berrett, Nick (14 November 2008). "Canal shark shock". Redcliffe & Bayside Herald. Quest Community Newspapers. Retrieved 26 March 2009. 
  18. ^ Shark Gallery. Bull shark (Carcharhinus leucas). sharks-med.netfirms.com
  19. ^ Coad, B. W. (2015). Review of the Freshwater Sharks of Iran (Family Carcharhinidae). International Journal of Aquatic Biology, 3(4), 218.
  20. ^ High number of sharks reported in Lake Pontchartrain. wwltv.com. 16 September 2006
  21. ^ "Sharks in Illinois". In-Fisherman. 16 July 2012. Retrieved 21 April 2017. 
  22. ^ "Bull Shark found in Ohio River". inquisitr.com. 12 September 2014. Retrieved 21 April 2017. 
  23. ^ 8-Foot Shark Caught In Potomac River. Nbcwashington.com. Retrieved on 4 May 2012.
  24. ^ Zauzmer, Julie (22 August 2013). "Man catches 2 Bull sharks in Potomac". Washington Post. 
  25. ^ Boswell, Thomas (1 May 2013). "Sharks at Carbrook Golf Club caught on film, confirming they survived Brisbane floods". Albert & Logan News. Retrieved 8 November 2017. 
  26. ^ "Shark-Infested Australian Golf Course Believed to Be World's First". Fox News. 11 October 2011. 
  27. ^ Compagno, Leonard I.V. & Cook, Sid F. (March 1995). "Freshwater elasmobranchs; a questionable future". Florida Museum of Natural History Ichthyology Department. Archived from the original on 5 July 2008. Retrieved 27 April 2011. 
  28. ^ a b c d e Heupel, Michelle R.; Colin A. Simpfendorfer (2008). "Movement and distribution of young bull sharks Carcharhinus leucas in a variable estuarine environment" (PDF). Aquatic Biology. 1: 277–289. doi:10.3354/ab00030. 
  29. ^ Tillett B., Meekan; M., Field; I., Thornburn; D., Ovenden, J. (2012). "Evidence for reproductive philopatry in the bull shark Carcharhinus leucas". Journal of Fish Biology. 80 (6): 2140–2158. doi:10.1111/j.1095-8649.2012.03228.x. CS1 maint: Multiple names: authors list (link)
  30. ^ Pillans, R.D.; Franklin, C.E. (2004). "Plasma osmolyte concentrations and rectal gland mass of bull sharks Carcharhinus leucas, captured along a salinity gradient". Comparative Biochemistry and Physiology A. 138 (3): 363–371. doi:10.1016/j.cbpb.2004.05.006. PMID 15313492. 
  31. ^ a b Pillans, R.D.; Good, J.P.; Anderson, W.G.; Hazon, N & Franklin, C.E. (2005). "Freshwater to seawater acclimation of juvenile bull sharks (Carcharhinus leucas): plasma osmolytes and Na+/K+-ATPase activity in gill, rectal gland, kidney and intestine" (PDF). Journal of Comparative Physiology B. 175 (1): 37–44. doi:10.1007/s00360-004-0460-2. PMID 15565307. 
  32. ^ Reilly, B.D.; Cramp, R.L.; Wilson, J.M.; Campbell, H.A & Franklin, C.E. (2011). "Branchial osmoregulation in the euryhaline bull shark, Carcharhinus leucas: a molecular analysis of ion transporters". Journal of Experimental Biology. 214 (17): 2883–2895. doi:10.1242/jeb.058156. PMID 21832131. 
  33. ^ Anderson, W.G.; Good, J.P.; Pillans, R.D.; Hazon, N & Franklin, C.E. (2005). "Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas". Journal of Experimental Zoology Part A: Comparative Experimental Biology. 303A (10): 917–921. doi:10.1002/jez.a.199. PMID 16161010. 
  34. ^ Gleiss, A. C.; Potvin, J.; Keleher, J. J.; Whitty, J. M.; Morgan, D. L.; Goldbogen, J. A. (2015). "Mechanical challenges to freshwater residency in sharks and rays". Journal of Experimental Biology. 218 (7): 1099–1110. doi:10.1242/jeb.114868. PMID 25573824. 
  35. ^ Montoya, Rafael Vasquez; Thorson, Thomas B. (1982). "The bull shark and largetooth sawfish in Lake Bayano, a tropical man-made impoundment in Panama". Environmental Biology of Fishes. 7 (4): 341–347. doi:10.1007/BF00005568. 
  36. ^ a b Fresh Waters: Unexpected Haunts. elasmo-research.org. Accessed 6 April 2008.
  37. ^ Kindersley, Dorling (2001) in Animal, David Burnie and Don E. Wilson (eds.) London & New York: Smithsonian Institution, ISBN 0789477645.
  38. ^ Snelson, Franklin F; Mulligan, Timothy J; Williams, Sherry E. (1 January 1984). "Food Habits, Occurrence, and Population Structure of the Bull Shark, Carcharhinus leucas, in Florida Coastal Lagoons". Bulletin of Marine Science. 1: 71–80. 
  39. ^ a b c Motta, Philip J; Wilga, Cheryl D. (2001). "Advances in the study of feeding behaviors, mechanisms, and mechanics or sharks". Environmental Biology of Fishes. 60 (1): 131–156. doi:10.1023/A:1007649900712. 
  40. ^ Bull Sharks, Carcharhinus leucas. Marinebio.org (14 January 2013). Retrieved on 30 November 2013.
  41. ^ Life of Bull Shark | Life of Sea. Life-sea.blogspot.com (15 November 2011).
  42. ^ Tuma, Robert E. (1976). "Reproduction of the Bull Shark, Carcharhinus leucas, in the Lake Nicaragua-Rio San Juan System". In Thorson, Thomas B. Investigation of the Icthyofauna of Nicaraguan Lakes. American Society of Ichthyologists and Herpetologists. 
  43. ^ Pacific Shark Research Center » Featured Elasmobranch – Bull Shark. Psrc.mlml.calstate.edu (16 February 2009). Retrieved on 30 November 2013.
  44. ^ a b c Fact Sheet: Bull Sharks. Sharkinfo.ch (15 October 1999). Retrieved on 30 November 2013.
  45. ^ Jenson, Norman H. (1976). "Reproduction of the Bull Shark, Carcharhinus leucas, in the Lake Nicaragua-Rio San Juan System". In Thorson, Thomas B. Investigation of the Icthyofauna of Nicaraguan Lakes. American Society of Ichthyologists and Herpetologists. 
  46. ^ a b c d Bres, M (1993). "The behaviour of sharks" (PDF). Reviews in Fish Biology and Fisheries. 3 (2): 133–159. doi:10.1007/BF00045229. 
  47. ^ a b Heupel, Michelle R.; Carlson, John K. & Simpfendorfer, Colin A. (14 May 2007). "Shark nursery areas: concepts, definition characterization and assumptions" (PDF). Marine Ecology Progress Series. 337: 289–297. doi:10.3354/meps337287. 
  48. ^ Handwerk, Brian. "Great Whites May Be Taking the Rap for Bull Shark Attacks". National Geographic News. Retrieved 1 February 2007. 
  49. ^ Quinn, Ben (15 March 2009). "Shark attacks bring panic to Sydney's shore". The Guardian. London. 
  50. ^ Frantz, Vickie (18 July 2011). "Bull Sharks Attacks Comonly in Warm, Shallow Waters". accuweather. 
  51. ^ a b c d Ortega, Lori A.; Heupel, Michelle R.; van Beynen, Philip & Motta, Philip J. (2009). "Movement patterns and water quality preferences of juvenile bull sharks (Carcharhinus lecuas) in a Florida estuary". Environmental Biology of Fishes. 84 (4): 361–373. doi:10.1007/s10641-009-9442-2. 
  52. ^ "No Bull: Saltwater Crocodile Eats Shark". UnderwaterTimes.com. 13 August 2007. Retrieved 15 June 2008. 
  53. ^ "FLMNH Ichthyology Department: Bull Shark". www.flmnh.ufl.edu. Retrieved 2015-10-23. 

Sources

External links

source: http://en.wikipedia.org/wiki/Bull_shark

Atlantic Needlefish

Atlantic Needlefish Gyotaku by Inked Animal
Atlantic Needlefish | Strongylura marina

Atlantic Needlefish Gyotaku by Inked Animal

 

Info via Wikipedia:

Strongylura marina
Fish4485 - Flickr - NOAA Photo Library.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Beloniformes
Family: Belonidae
Genus: Strongylura
Species: S. marina
Binomial name
Strongylura marina
(Walbaum, 1792)

Strongylura marina, known commonly as the Atlantic needlefish, is a common demersal needlefish species common in marinas and other areas with minimal current. Its extremely long jaw and body set this fish apart from other predators. Atlantic needlefish are found from Maine to Brazil and have been known to venture into freshwater for short periods.

Geographic range

Strongylura marina is found along western Atlantic coastal waters from Maine to southern Brazil, including areas along the coast of the Gulf of Mexico and Caribbean.[2][3] Atlantic needlefish are not restricted to ocean waters; they can be found in various estuaries and are capable of ascending well upstream into freshwater. S. marina is found in shallow waters throughout the Chesapeake Bay.[4] In Texas, S. marina is known to inhabit the following drainage units: Sabine Lake (including minor coastal drainages west to Galveston Bay), Galveston Bay (including minor coastal drainages west to mouth of Brazos River), Brazos River, Colorado River, San Antonio Bay (including minor coastal drainages west of mouth of Colorado River to mouth of Nueces River), Nueces River.[5]S. marina has also been introduced and now inhabits parts of the Tennessee River drainage throughout Alabama and Tennessee.[6]

Ecology

As juveniles, the diet of S. marina consists of 70% shrimp, mysids and amphipods and 30% fish, while adults are exclusively piscivorous.[7]

The predators of S. marina include larger piscivorous fish such as the Atlantic tarpon (Megalops atlanticus).[8] There are also less common predators that include S. marina in their diet such as the common bottlenose dolphin (Tursiops truncatus) and juvenile lemon sharks (Negaprion brevirostris).[9] Since they are surface swimmers, S. marina are also preyed upon by some birds. The competitors of S. marina include similar sized piscivorous fish species such as bonefish. Although the maximum salinity of Strongylura marina is 36.9 ppt,[8] they are able to adapt to a wide range of salinities, regularly venturing into fresh water.[3]

Life history

Spawning typically occurs in late spring and summer. In Texas, near ripe females have been reported in February.[8] Females lay eggs that have many long filamentous tendrils which attach to floating vegetation or other submerged objects and organisms. S. marina reaches reproductive maturity two years after being born. Spawning activity occurs in shallow inshore habitats with submerged algal masses.[2]

S. marina depends on submerged vegetation for breeding and shelter. In the Gulf of Mexico, the eggs of S. marina attach to sargassum seaweed.

Conservation

S. marina is not currently considered to be a threatened species. It is not of high commercial importance, but there is a fishery for it and it is sometimes taken as bycatch. Sport fishermen take it by angling and seining, and then use it as bait.[1]

Common names

Other common names for the fish include agujon, billfish, bluebone, garfish, green gar, harvest pike, northern needlefish, saltwater gar, sea pike, and silver gar.[1]

References

  1. ^ a b c Collen, B., et al. (Sampled Red List Index Coordinating Team) 2010. Strongylura marina. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. Downloaded on 06 June 2013.
  2. ^ a b Foster, N. R. 1974. Strongylura marina-Atlantic Needlefish. Manual for identification of early developmental stages of fishes of the Potomac River estuary. Environmental Technology Center, Marietta Corp., Baltimore, Md. 125-126.
  3. ^ a b Collette, B B. (1968). "Strongylura timucu (Wallbaum): A valid species of Western Atlantic needlefish". Copeia. 1968 (1): 189–192. doi:10.2307/1441578. JSTOR 1441578. 
  4. ^ Berry, F. H. & Rivas, L. R. (1962). "Data on six species of needlefishes (Belonidae) from the western Atlantic". Copeia. 1962: 152–160. doi:10.2307/1439490. JSTOR 1439490. 
  5. ^ Warren, M.L. Jr., B.M. Burr, S. J. Walsh, H.L. Bart Jr., R. C. Cashner, D.A. Etnier, B. J. Freeman, B.R. Kuhajda, R.L. Mayden, H. W. Robison, S.T. Ross & W. C. Starnes (2000). "Diversity, distribution and conservation status of the native freshwater fishes of the southern United States". Fisheries. 25: 7–29. doi:10.1577/1548-8446(2000)025<0007:DDACSO>2.0.CO;2. CS1 maint: Multiple names: authors list (link)
  6. ^ Boschung, H. T. (1992). "Catalogue of freshwater and marine fishes of Alabama". Alabama Museum of Natural History Bulletin. 14: 1–266. 
  7. ^ Carr, W. E. S. & Adam, C. A. (1973). "Food habits of juvenile marine fishes occupying seagrass beds in the estuarine zone near Crystal River, Florida". Transactions of the American Fisheries Society. 102: 511–540. doi:10.1577/1548-8659(1973)102<511:FHOJMF>2.0.CO;2. 
  8. ^ a b c Hardy, J. D, Jr. 1978. Development of fishes of the mid-Atlantic bight. Vol. II. Anguillidae through Syngnathidae. U.S. Fish and Wildlife Service, Biological Service Program: pp 458.
  9. ^ Gunter G. (1942). "Contributions to the natural history of the bottlenose dolphin, Tursiops truncatus (Montague), on the Texas coast, with particular reference to food habits". Journal of Mammalogy. 23: 267–276. doi:10.2307/1374993. 

External links

source: http://en.wikipedia.org/wiki/Strongylura_marina

Blacktip Shark 3

 

Blacktip Shark Gyotaku #3 by Inked Animal

Blacktip Shark | Carcharhinus limbatus


Blacktip Shark info via Wikipedia:

Not to be confused with the blacktip reef shark, Carcharhinus melanopterus.
Blacktip shark
Carcharhinus limbatus (2).jpg
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Carcharhiniformes
Family: Carcharhinidae
Genus: Carcharhinus
Species: C. limbatus
Binomial name
Carcharhinus limbatus
(J. P. Müller & Henle, 1839)
Carcharhinus limbatus distmap.png
Range of the blacktip shark
Synonyms

Carcharias abbreviatus Klunzinger, 1871
Carcharias aethalorus Jordan & Gilbert, 1882
Carcharias ehrenbergi Klunzinger, 1871
Carcharias maculipinna Günther, 1868
Carcharias microps Lowe, 1841
Carcharias muelleri Steindachner, 1867
Carcharias phorcys Jordan & Evermann, 1903
Carcharias pleurotaenia Bleeker, 1852
Carcharhinus natator Meek & Hildebrand, 1923

The blacktip shark (Carcharhinus limbatus) is a species of requiem shark, and part of the family Carcharhinidae. It is common to coastal tropical and subtropical waters around the world, including brackish habitats. Genetic analyses have revealed substantial variation within this species, with populations from the western Atlantic Ocean isolated and distinct from those in the rest of its range. The blacktip shark has a stout, fusiform body with a pointed snout, long gill slits, and no ridge between the dorsal fins. Most individuals have black tips or edges on the pectoral, dorsal, pelvic, and caudal fins. It usually attains a length of 1.5 m (4.9 ft).

Swift, energetic piscivores, blacktip sharks are known to make spinning leaps out of the water while attacking schools of small fish. Their demeanor has been described as "timid" compared to other large requiem sharks. Both juveniles and adults form groups of varying size. Like other members of its family, the blacktip shark is viviparous; females bear one to 10 pups every other year. Young blacktip sharks spend the first months of their lives in shallow nurseries, and grown females return to the nurseries where they were born to give birth themselves. In the absence of males, females are also capable of asexual reproduction.

Normally wary of humans, blacktip sharks can become aggressive in the presence of food and have been responsible for a number of attacks on people. This species is of importance to both commercial and recreational fisheries across many parts of its range, with its meat, skin, fins, and liver oil used. It has been assessed as Near Threatened by the IUCN, on the basis of its low reproductive rate and high value to fishers.

Taxonomy

The blacktip shark was first described by French zoologist Achille Valenciennes as Carcharias (Prionodon) limbatus in Johannes Müller and Friedrich Henle's 1839 Systematische Beschreibung der Plagiostomen. The type specimens were two individuals caught off Martinique, both of which have since been lost. Later authors moved this species to the genus Carcharhinus.[1][2] The specific epithet limbatus is Latin for "bordered", referring to the black edges of this shark's fins.[3] Other common names used for the blacktip shark include blackfin shark, blacktip whaler, common or small blacktip shark, grey shark, and spotfin ground shark.[4]

Phylogeny and evolution

The closest relatives of the blacktip shark were originally thought to be the graceful shark (C. amblyrhynchoides) and the spinner shark (C. brevipinna), due to similarities in morphology and behavior. However, this interpretation has not been borne out by studies of mitochondrial and ribosomal DNA, which instead suggest affinity with the blacknose shark (C. acronotus). More work is required to fully resolve the relationship between the blacktip shark and other Carcharhinus species.[5]

Analysis of mitochondrial DNA has also revealed two distinct lineages within this species, one occupying the western Atlantic and the other occupying the eastern Atlantic, Indian, and Pacific Oceans. This suggests that Indo-Pacific blacktip sharks are descended from those in the eastern Atlantic, while the western Atlantic sharks became isolated by the widening Atlantic Ocean on one side and the formation of the Isthmus of Panama on the other. Blacktip sharks from these two regions differ in morphology, coloration, and life history characteristics, and the eastern Atlantic lineage may merit species status.[6] Fossil teeth belonging to this species have been found in Early Miocene (23–16 Ma) deposits in Delaware and Florida.[7][8]

Description

The blacktip shark has a robust, streamlined body with a long, pointed snout and relatively small eyes. The five pairs of gill slits are longer than those of similar requiem shark species.[1] The jaws contain 15 tooth rows on either side, with two symphysial teeth (at the jaw midline) in the upper jaw and one symphysial tooth in the lower jaw. The teeth are broad-based with a high, narrow cusp and serrated edges.[2] The first dorsal fin is tall and falcate (sickle-shaped) with a short free rear tip; no ridge runs between the first and second dorsal fins. The large pectoral fins are falcate and pointed.[1]

The coloration is gray to brown above and white below, with a conspicuous white stripe running along the sides. The pectoral fins, second dorsal fin, and the lower lobe of the caudal fin usually have black tips. The pelvic fins and rarely the anal fin may also be black-tipped. The first dorsal fin and the upper lobe of the caudal fin typically have black edges.[1] Some larger individuals have unmarked or nearly unmarked fins.[3] Blacktip sharks can temporarily lose almost all their colors during blooms, or "whitings", of coccolithophores.[9] This species attains a maximum known length of 2.8 m (9.2 ft), though 1.5 m (4.9 ft) is more typical, and a maximum known weight of 123 kg (271 lb).[4]

Distribution and habitat

A blacktip shark swimming in murky water off Oahu, Hawaii

The blacktip shark has a worldwide distribution in tropical and subtropical waters. In the Atlantic, it is found from Massachusetts to Brazil, including the Gulf of Mexico and the Caribbean Sea, and from the Mediterranean Sea, Madeira, and the Canary Islands to the Democratic Republic of the Congo. It occurs all around the periphery of the Indian Ocean, from South Africa and Madagascar to the Arabian Peninsula and the Indian subcontinent, to Southeast Asia. In the western Pacific, it is found from the Ryukyu Islands of Japan[10] to northern Australia, including southern China, the Philippines and Indonesia. In the eastern Pacific, it occurs from Baja California to Peru. It has also been reported at a number of Pacific islands, including New Caledonia, Tahiti, the Marquesas, Hawaii, Revillagigedo, and the Galápagos.[1]

Most blacktip sharks are found in water less than 30 m (98 ft) deep over continental and insular shelves, though they may dive to 64 m (210 ft).[4] Favored habitats are muddy bays, island lagoons, and the drop-offs near coral reefs; they are also tolerant of low salinity and enter estuaries and mangrove swamps. Although an individual may be found some distance offshore, blacktip sharks do not inhabit oceanic waters.[1] Seasonal migration has been documented for the population off the east coast of the United States, moving north to North Carolina in the summer and south to Florida in the winter.[11]

Biology and ecology

The blacktip shark is an extremely fast, energetic predator that is usually found in groups of varying size.[3] Segregation by sex and age does not occur; adult males and nonpregnant females are found apart from pregnant females, and both are separated from juveniles.[1] In Terra Ceia Bay, Florida, a nursery area for this species, juvenile blacktips form aggregations during the day and disperse at night. They aggregate most strongly in the early summer when the sharks are youngest, suggesting that they are seeking refuge from predators (mostly larger sharks) in numbers.[12] Predator avoidance may also be the reason why juvenile blacktips do not congregate in the areas of highest prey density in the bay.[13] Adults have no known predators.[2] Known parasites of the blacktip shark include the copepods Pandarus sinuatus and P. smithii, and the monogeneans Dermophthirius penneri and Dionchus spp., which attach the shark's skin.[2][14][15] This species is also parasitized by nematodes in the family Philometridae, which infest the ovaries.[16]

Behaviour

Blacktip sharks are social and usually found in groups.

Like the spinner shark, the blacktip shark is known to leap out of the water and spin three or four times about its axis before landing. Some of these jumps are the end product of feeding runs, in which the shark corkscrews vertically through schools of small fish and its momentum launches it into the air.[3] Observations in the Bahamas suggest that blacktip sharks may also jump out of the water to dislodge attached sharksuckers (Echeneis naucrates), which irritate the shark's skin and compromise its hydrodynamic shape.[17] The speed attained by the shark during these jumps has been estimated to average 6.3 m/s (21 ft/s).[18]

Blacktip sharks have a timid disposition and consistently lose out to Galapagos sharks (C. galapagensis) and silvertip sharks (C. albimarginatus) of equal size when competing for food.[1] If threatened or challenged, they may perform an agonistic display: the shark swims towards the threat and then turns away, while rolling from side to side, lowering its pectoral fins, tilting its head and tail upwards, and making sideways biting motions. The entire sequence lasts around 25 seconds. This behavior is similar to the actions of a shark attempting to move a sharksucker; one of these behaviors possibly is derived from the other.[19]

Feeding

Fish make up some 90% of the blacktip shark's diet.[20] A wide variety of fish have been recorded as prey for this species: sardines, herring, anchovies, ladyfish, sea catfish, cornetfish, flatfish, threadfins, mullet, mackerel, jacks, groupers, snook, porgies, mojarras, emperors, grunts, butterfish, tilapia, triggerfish, boxfish, and porcupinefish. They also feed on rays and skates, as well as smaller sharks such as smoothhounds and sharpnose sharks. Crustaceans and cephalopods are occasionally taken.[1] In the Gulf of Mexico, the most important prey of the blacktip shark is the Gulf menhaden (Brevoortia patronus), followed by the Atlantic croaker (Micropogonias undulatus).[20] Off South Africa, jacks and herring are the most important prey.[21] Hunting peaks at dawn and dusk.[20] The excitability and sociability of blacktip sharks makes them prone to feeding frenzies when large quantities of food are suddenly available, such as when fishing vessels dump their refuse overboard.[1]

Life history

As with other requiem sharks, the blacktip shark exhibits vivipary. Females typically give birth to four to seven (range one to 10) pups every other year, making use of shallow coastal nurseries that offer plentiful food and fewer predators.[1] Known nurseries include Pine Island Sound, Terra Ceia Bay, and Yankeetown along the Gulf Coast of Florida, Bulls Bay on the coast of South Carolina, and Pontal do Paraná on the coast of Brazil.[22][23] Although adult blacktip sharks are highly mobile and disperse over long distances, they are philopatric and return to their original nursery areas to give birth. This results in a series of genetically distinct breeding stocks that overlap in geographic range.[22][24]

Mating occurs from spring to early summer, and the young are born around the same time the following year after a gestation period of 10–12 months.[1] Females have one functional ovary and two functional uteri; each uterus is separated into compartments with a single embryo inside each.[25] The embryos are initially sustained by a yolk sac; in the 10th or 11th week of gestation, when the embryo measures 18–19 cm long (7.1–7.5 in), the supply of yolk is exhausted and the yolk sac develops into a placental connection that sustains the embryo until birth.[11] The length at birth is 55–60 cm (22–24 in) off the eastern United States and 61–65 cm (24–26 in) off North Africa.[11][25] The mortality rate in the first 15 months of life is 61–91%, with major threats being predation and starvation.[26] The young remain in the nurseries until their first fall, when they migrate to their wintering grounds.[11]

The growth rate of this species slows with age: 25–30 cm (9.8–11.8 in) in the first six months, then 20 cm (7.9 in) a year until the second year, then 10 cm (3.9 in) a year until maturation, then 5 cm (2.0 in) a year for adults.[27][28] The size at maturity varies geographically: males and females mature at 1.4–1.5 m (4.6–4.9 ft) and 1.6 m (5.2 ft), respectively, in the northeastern Atlantic,[11] 1.3–1.4 m (4.3–4.6 ft) and 1.5–1.6 m (4.9–5.2 ft), respectively, in the Gulf of Mexico,[27][29] 1.5 and 1.6 m (4.9 and 5.2 ft) respectively off South Africa,[30] and 1.7 and 1.8 m (5.6 and 5.9 ft), respectively, off North Africa.[25] The age at maturation is 4–5 years for males and 7–8 years for females.[27][29] The lifespan is at least 12 years.[1]

In 2007, a 9-year-old female blacktip shark at the Virginia Aquarium and Marine Science Center was found to be pregnant with a single near-term female pup, despite having never mated with a male. Genetic analysis confirmed that her offspring was the product of automictic parthenogenesis, a form of asexual reproduction in which an ovum merges with a polar body to form a zygote without fertilization. Along with an earlier case of parthenogenesis in the bonnethead (Sphyrna tiburo), this event suggests that asexual reproduction may be more widespread in sharks than previously thought.[31]

Human interactions

The blacktip shark usually poses little danger to divers.

Blacktip sharks showing curiosity towards divers has been reported, but they remain at a safe distance. Under most circumstances, these timid sharks are not regarded as highly dangerous to humans. However, they may become aggressive in the presence of food, and their size and speed invite respect.[1] As of 2008, the International Shark Attack File lists 28 unprovoked attacks (one fatal) and 13 provoked attacks by this species.[32] Blacktip sharks are responsible annually for 16% of the shark attacks around Florida. Most attacks by this species result in only minor wounds.[2]

As one of the most common large sharks in coastal waters, the blacktip shark is caught in large numbers by commercial fisheries throughout the world, using longlines, fixed-bottom nets, bottom trawls, and hook-and-line. The meat is of high quality and marketed fresh, frozen, or dried and salted. In addition, the fins are used for shark fin soup, the skin for leather, the liver oil for vitamins, and the carcasses for fishmeal.[1] Blacktip sharks are one of the most important species to the northwestern Atlantic shark fishery, second only to the sandbar shark (C. plumbeus). The flesh is considered superior to that of the sandbar shark, resulting in the sandbar and other requiem shark species being sold under the name "blacktip shark" in the United States. The blacktip shark is also very significant to Indian and Mexican fisheries, and is caught in varying numbers by fisheries in the Mediterranean and South China Seas, and off northern Australia.[28]

The blacktip shark is popular with recreational anglers in Florida, the Caribbean, and South Africa. It is listed as a game fish by the International Game Fish Association. Once hooked, this species is a strong, steady fighter that sometimes jumps out of the water.[2] Since 1995, the number of blacktip sharks taken by recreational anglers in the United States has approached or surpassed the number taken by commercial fishing.[28] The International Union for Conservation of Nature has assessed the blacktip shark as Near Threatened, as its low reproductive rate renders it vulnerable to overfishing.[33] The United States and Australia are the only two countries that manage fisheries catching blacktip sharks. In both cases, regulation occurs under umbrella management schemes for multiple shark species, such as that for the large coastal sharks category of the US National Marine Fisheries Service Atlantic shark Fisheries Management Plan. No conservation plans specifically for this species have been implemented.[28]

References

  1. ^ a b c d e f g h i j k l m n o Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Rome: Food and Agricultural Organization. pp. 481–483. ISBN 92-5-101384-5. 
  2. ^ a b c d e f Curtis, T. Biological Profiles: Blacktip Shark. Florida Museum of Natural History Ichthyology Department. Retrieved on April 27, 2009.
  3. ^ a b c d Ebert, D.A. (2003). Sharks, Rays, and Chimaeras of California. London: University of California Press. pp. 156–157. ISBN 0-520-23484-7. 
  4. ^ a b c Froese, Rainer and Pauly, Daniel, eds. (2009). "Carcharhinus limbatus" in FishBase. April 2009 version.
  5. ^ Dosay-Akbulut, M. (2008). "The phylogenetic relationship within the genus Carcharhinus". Comptes Rendus Biologies. 331 (7): 500–509. doi:10.1016/j.crvi.2008.04.001. PMID 18558373. 
  6. ^ Keeney, D.B. & Heist, E.J. (October 2006). "Worldwide phylogeography of the blacktip shark (Carcharhinus limbatus) inferred from mitochondrial DNA reveals isolation of western Atlantic populations coupled with recent Pacific dispersal". Molecular Ecology. 15 (12): 3669–3679. doi:10.1111/j.1365-294X.2006.03036.x. PMID 17032265. 
  7. ^ Benson. R.N., ed. (1998). Geology and Paleontology of the Lower Miocene Pollack Farm Fossil Site, Delaware: Delaware Geological Survey Special Publication No. 21. Delaware Natural History Survey. pp. 133–139. 
  8. ^ Brown, R.C. (2008). Florida's Fossils: Guide to Location, Identification, and Enjoyment (third ed.). Pineapple Press Inc. p. 100. ISBN 1-56164-409-9. 
  9. ^ Martin, R.A. Albinism in Sharks. ReefQuest Centre for Shark Research. Retrieved on April 28, 2009.
  10. ^ Yano, Kazunari; Morrissey, John F. (1999-06-01). "Confirmation of blacktip shark,Carcharhinus limbatus, in the Ryukyu Islands and notes on possible absence ofC. melanopterus in Japanese waters". Ichthyological Research. 46 (2): 193–198. doi:10.1007/BF02675438. ISSN 1341-8998. 
  11. ^ a b c d e Castro, J.I. (November 1996). "Biology of the blacktip shark, Carcharhinus limbatus, off the southeastern United States". Bulletin of Marine Science. 59 (3): 508–522. 
  12. ^ Heupel, M.R. & Simpfendorfer, C.A. (2005). "Quantitative analysis of aggregation behavior in juvenile blacktip sharks". Marine Biology. 147 (5): 1239–1249. doi:10.1007/s00227-005-0004-7. 
  13. ^ Heupel, M.R. & Hueter, R.E. (2002). "The importance of prey density in relation to the movement patterns of juvenile sharks within a coastal nursery area". Marine and Freshwater Research. 53 (2): 543–550. doi:10.1071/MF01132. 
  14. ^ Bullard, S.A.; Frasca, A. (Jr.) & Benz, G.W. (June 2000). "Skin Lesions Caused by Dermophthirius penneri (Monogenea: Microbothriidae) on Wild-Caught Blacktip Sharks (Carcharhinus limbatus)". Journal of Parasitology. 86 (3): 618–622. doi:10.1645/0022-3395(2000)086[0618:SLCBDP]2.0.CO;2. PMID 10864264. 
  15. ^ Bullard, S.A.; Benz, G.W. & Braswell, J.S. (2000). "Dionchus postoncomiracidia (Monogenea: Dionchidae) from the skin of blacktip sharks, Carcharhinus limbatus (Carcharhinidae)". Journal of Parasitology. 86 (2): 245–250. doi:10.1645/0022-3395(2000)086[0245:DPMDFT]2.0.CO;2. JSTOR 3284763. PMID 10780540. 
  16. ^ Rosa-Molinar, E. & Williams, C.S. (1983). "Larval nematodes (Philometridae) in granulomas in ovaries of blacktip sharks, Carcharhinus limbatus (Valenciennes)". Journal of Wildlife Diseases. 19 (3): 275–277. doi:10.7589/0090-3558-19.3.275. PMID 6644926. 
  17. ^ Riner, E.K. & Brijnnschweiler, J.M. (2003). "Do sharksuckers, Echeneis naucrates, induce jump behaviour in blacktip sharks, Carcharhinus limbatus?". Marine and Freshwater Behaviour and Physiology. 36 (2): 111–113. doi:10.1080/1023624031000119584. 
  18. ^ Brunnschweiler, J.M. (2005). "Water-escape velocities in jumping blacktip sharks". Journal of the Royal Society Interface. 2 (4): 389–391. doi:10.1098/rsif.2005.0047. PMC 1578268Freely accessible. PMID 16849197. 
  19. ^ Ritter, E.K. & Godknecht, A.J. (February 1, 2000). Ross, S. T., ed. "Agonistic Displays in the Blacktip Shark (Carcharhinus limbatus)". Copeia. 2000 (1): 282–284. doi:10.1643/0045-8511(2000)2000[0282:ADITBS]2.0.CO;2. JSTOR 1448264. 
  20. ^ a b c Barry, K.P. (2002). Feeding habits of blacktip sharks, Carcharhinus limbatus, and Atlantic sharpnose sharks, Rhizoprionodon terraenovae, in Louisiana coastal waters. MS thesis, Louisiana State University, Baton Rouge.
  21. ^ Dudley, S.F.J. & Cliff, G. (1993). "Sharks caught in the protective gill nets off Natal, South Africa. 7. The blacktip shark Carcharhinus limbatus (Valenciennes)". African Journal of Marine Science. 13: 237–254. doi:10.2989/025776193784287356. 
  22. ^ a b Keeney, D.B.; Heupel, M.; Hueter, R.E. & Heist, E.J. (2003). "Genetic heterogeneity among blacktip shark, Carcharhinus limbatus, continental nurseries along the U.S. Atlantic and Gulf of Mexico". Marine Biology. 143 (6): 1039–1046. doi:10.1007/s00227-003-1166-9. 
  23. ^ Bornatowski, H. (2008). "A parturition and nursery area for Carcharhinus limbatus (Elasmobranchii, Carcharhinidae) off the coast of Paraná, Brazil". Brazilian Journal of Oceanography. 56 (4): 317–319. doi:10.1590/s1679-87592008000400008. 
  24. ^ Keeney, D.B.; Heupel, M.R.; Hueter, R.E. & Heist, E.J. (2005). "Microsatellite and mitochondrial DNA analyses of the genetic structure of blacktip shark (Carcharhinus limbatus) nurseries in the northwestern Atlantic, Gulf of Mexico, and Caribbean Sea". Molecular Ecology. 14 (7): 1911–1923. doi:10.1111/j.1365-294X.2005.02549.x. PMID 15910315. 
  25. ^ a b c Capapé, C.H.; Seck, A.A.; Diatta, Y.; Reynaud, C.H.; Hemida, F. & Zaouali, J. (2004). "Reproductive biology of the blacktip shark, Carcharhinus limbatus (Chondrichthyes: Carcharhinidae) off West and North African Coasts" (PDF). Cybium. 28 (4): 275–284. 
  26. ^ Heupel, M.R. & Simpfendorfer, C.A. (2002). "Estimation of mortality of juvenile blacktip sharks, Carcharhinus limbatus, within a nursery area using telemetry data". Canadian Journal of Fisheries and Aquatic Sciences. 59 (4): 624–632. doi:10.1139/f02-036. 
  27. ^ a b c Branstetter, S. (December 9, 1987). "Age and Growth Estimates for Blacktip, Carcharhinus limbatus, and Spinner, C. brevipinna, Sharks from the Northwestern Gulf of Mexico". Copeia. American Society of Ichthyologists and Herpetologists. 1987 (4): 964–974. doi:10.2307/1445560. JSTOR 1445560. 
  28. ^ a b c d Fowler, S.L.; Cavanagh, R.D.; Camhi, M.; Burgess, G.H.; Cailliet, G.M.; Fordham, S.V.; Simpfendorfer, C.A. & Musick, J.A. (2005). Sharks, Rays and Chimaeras: The Status of the Chondrichthyan Fishes. International Union for Conservation of Nature and Natural Resources. pp. 106–109, 293–295. ISBN 2-8317-0700-5. 
  29. ^ a b Killam, K.A. & Parsons, G.R. (May 1989). "Age and Growth of the Blacktip Shark, Carcharhinus limbatus, near Tampa Bay" (PDF). Florida Fishery Bulletin. 87: 845–857. 
  30. ^ Wintner, S.P. & Cliff, G. (1996). "Age and growth determination of the blacktip shark, Carcharhinus limbatus, from the east coast of South Africa" (PDF). Fishery Bulletin. 94 (1): 135–144. 
  31. ^ Chapman, D.D.; Firchau, B. & Shivji, M.S. (2008). "Parthenogenesis in a large-bodied requiem shark, the blacktip Carcharhinus limbatus". Journal of Fish Biology. 73 (6): 1473–1477. doi:10.1111/j.1095-8649.2008.02018.x. 
  32. ^ ISAF Statistics on Attacking Species of Shark. International Shark Attack File, Florida Museum of Natural History, University of Florida. Retrieved on April 22, 2009.
  33. ^ Musick, J.A.; Fowler, S. (2000). "Carcharhinus limbatus". IUCN Red List of Threatened Species. Version 2007. International Union for Conservation of Nature. Retrieved April 27, 2009. 
source: http://en.wikipedia.org/wiki/Blacktip_shark

Blacktip Shark 2

Blacktip Shark 2 by Inked Animal

Blacktip Shark | Carcharhinus limbatus



Blacktip Shark info via Wikipedia:

Not to be confused with the blacktip reef shark, Carcharhinus melanopterus.
Blacktip shark
Carcharhinus limbatus (2).jpg
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Carcharhiniformes
Family: Carcharhinidae
Genus: Carcharhinus
Species: C. limbatus
Binomial name
Carcharhinus limbatus
(J. P. Müller & Henle, 1839)
Carcharhinus limbatus distmap.png
Range of the blacktip shark
Synonyms

Carcharias abbreviatus Klunzinger, 1871
Carcharias aethalorus Jordan & Gilbert, 1882
Carcharias ehrenbergi Klunzinger, 1871
Carcharias maculipinna Günther, 1868
Carcharias microps Lowe, 1841
Carcharias muelleri Steindachner, 1867
Carcharias phorcys Jordan & Evermann, 1903
Carcharias pleurotaenia Bleeker, 1852
Carcharhinus natator Meek & Hildebrand, 1923

The blacktip shark (Carcharhinus limbatus) is a species of requiem shark, and part of the family Carcharhinidae. It is common to coastal tropical and subtropical waters around the world, including brackish habitats. Genetic analyses have revealed substantial variation within this species, with populations from the western Atlantic Ocean isolated and distinct from those in the rest of its range. The blacktip shark has a stout, fusiform body with a pointed snout, long gill slits, and no ridge between the dorsal fins. Most individuals have black tips or edges on the pectoral, dorsal, pelvic, and caudal fins. It usually attains a length of 1.5 m (4.9 ft).

Swift, energetic piscivores, blacktip sharks are known to make spinning leaps out of the water while attacking schools of small fish. Their demeanor has been described as "timid" compared to other large requiem sharks. Both juveniles and adults form groups of varying size. Like other members of its family, the blacktip shark is viviparous; females bear one to 10 pups every other year. Young blacktip sharks spend the first months of their lives in shallow nurseries, and grown females return to the nurseries where they were born to give birth themselves. In the absence of males, females are also capable of asexual reproduction.

Normally wary of humans, blacktip sharks can become aggressive in the presence of food and have been responsible for a number of attacks on people. This species is of importance to both commercial and recreational fisheries across many parts of its range, with its meat, skin, fins, and liver oil used. It has been assessed as Near Threatened by the IUCN, on the basis of its low reproductive rate and high value to fishers.

Taxonomy

The blacktip shark was first described by French zoologist Achille Valenciennes as Carcharias (Prionodon) limbatus in Johannes Müller and Friedrich Henle's 1839 Systematische Beschreibung der Plagiostomen. The type specimens were two individuals caught off Martinique, both of which have since been lost. Later authors moved this species to the genus Carcharhinus.[1][2] The specific epithet limbatus is Latin for "bordered", referring to the black edges of this shark's fins.[3] Other common names used for the blacktip shark include blackfin shark, blacktip whaler, common or small blacktip shark, grey shark, and spotfin ground shark.[4]

Phylogeny and evolution

The closest relatives of the blacktip shark were originally thought to be the graceful shark (C. amblyrhynchoides) and the spinner shark (C. brevipinna), due to similarities in morphology and behavior. However, this interpretation has not been borne out by studies of mitochondrial and ribosomal DNA, which instead suggest affinity with the blacknose shark (C. acronotus). More work is required to fully resolve the relationship between the blacktip shark and other Carcharhinus species.[5]

Analysis of mitochondrial DNA has also revealed two distinct lineages within this species, one occupying the western Atlantic and the other occupying the eastern Atlantic, Indian, and Pacific Oceans. This suggests that Indo-Pacific blacktip sharks are descended from those in the eastern Atlantic, while the western Atlantic sharks became isolated by the widening Atlantic Ocean on one side and the formation of the Isthmus of Panama on the other. Blacktip sharks from these two regions differ in morphology, coloration, and life history characteristics, and the eastern Atlantic lineage may merit species status.[6] Fossil teeth belonging to this species have been found in Early Miocene (23–16 Ma) deposits in Delaware and Florida.[7][8]

Description

The blacktip shark has a robust, streamlined body with a long, pointed snout and relatively small eyes. The five pairs of gill slits are longer than those of similar requiem shark species.[1] The jaws contain 15 tooth rows on either side, with two symphysial teeth (at the jaw midline) in the upper jaw and one symphysial tooth in the lower jaw. The teeth are broad-based with a high, narrow cusp and serrated edges.[2] The first dorsal fin is tall and falcate (sickle-shaped) with a short free rear tip; no ridge runs between the first and second dorsal fins. The large pectoral fins are falcate and pointed.[1]

The coloration is gray to brown above and white below, with a conspicuous white stripe running along the sides. The pectoral fins, second dorsal fin, and the lower lobe of the caudal fin usually have black tips. The pelvic fins and rarely the anal fin may also be black-tipped. The first dorsal fin and the upper lobe of the caudal fin typically have black edges.[1] Some larger individuals have unmarked or nearly unmarked fins.[3] Blacktip sharks can temporarily lose almost all their colors during blooms, or "whitings", of coccolithophores.[9] This species attains a maximum known length of 2.8 m (9.2 ft), though 1.5 m (4.9 ft) is more typical, and a maximum known weight of 123 kg (271 lb).[4]

Distribution and habitat

A blacktip shark swimming in murky water off Oahu, Hawaii

The blacktip shark has a worldwide distribution in tropical and subtropical waters. In the Atlantic, it is found from Massachusetts to Brazil, including the Gulf of Mexico and the Caribbean Sea, and from the Mediterranean Sea, Madeira, and the Canary Islands to the Democratic Republic of the Congo. It occurs all around the periphery of the Indian Ocean, from South Africa and Madagascar to the Arabian Peninsula and the Indian subcontinent, to Southeast Asia. In the western Pacific, it is found from the Ryukyu Islands of Japan[10] to northern Australia, including southern China, the Philippines and Indonesia. In the eastern Pacific, it occurs from Baja California to Peru. It has also been reported at a number of Pacific islands, including New Caledonia, Tahiti, the Marquesas, Hawaii, Revillagigedo, and the Galápagos.[1]

Most blacktip sharks are found in water less than 30 m (98 ft) deep over continental and insular shelves, though they may dive to 64 m (210 ft).[4] Favored habitats are muddy bays, island lagoons, and the drop-offs near coral reefs; they are also tolerant of low salinity and enter estuaries and mangrove swamps. Although an individual may be found some distance offshore, blacktip sharks do not inhabit oceanic waters.[1] Seasonal migration has been documented for the population off the east coast of the United States, moving north to North Carolina in the summer and south to Florida in the winter.[11]

Biology and ecology

The blacktip shark is an extremely fast, energetic predator that is usually found in groups of varying size.[3] Segregation by sex and age does not occur; adult males and nonpregnant females are found apart from pregnant females, and both are separated from juveniles.[1] In Terra Ceia Bay, Florida, a nursery area for this species, juvenile blacktips form aggregations during the day and disperse at night. They aggregate most strongly in the early summer when the sharks are youngest, suggesting that they are seeking refuge from predators (mostly larger sharks) in numbers.[12] Predator avoidance may also be the reason why juvenile blacktips do not congregate in the areas of highest prey density in the bay.[13] Adults have no known predators.[2] Known parasites of the blacktip shark include the copepods Pandarus sinuatus and P. smithii, and the monogeneans Dermophthirius penneri and Dionchus spp., which attach the shark's skin.[2][14][15] This species is also parasitized by nematodes in the family Philometridae, which infest the ovaries.[16]

Behaviour

Blacktip sharks are social and usually found in groups.

Like the spinner shark, the blacktip shark is known to leap out of the water and spin three or four times about its axis before landing. Some of these jumps are the end product of feeding runs, in which the shark corkscrews vertically through schools of small fish and its momentum launches it into the air.[3] Observations in the Bahamas suggest that blacktip sharks may also jump out of the water to dislodge attached sharksuckers (Echeneis naucrates), which irritate the shark's skin and compromise its hydrodynamic shape.[17] The speed attained by the shark during these jumps has been estimated to average 6.3 m/s (21 ft/s).[18]

Blacktip sharks have a timid disposition and consistently lose out to Galapagos sharks (C. galapagensis) and silvertip sharks (C. albimarginatus) of equal size when competing for food.[1] If threatened or challenged, they may perform an agonistic display: the shark swims towards the threat and then turns away, while rolling from side to side, lowering its pectoral fins, tilting its head and tail upwards, and making sideways biting motions. The entire sequence lasts around 25 seconds. This behavior is similar to the actions of a shark attempting to move a sharksucker; one of these behaviors possibly is derived from the other.[19]

Feeding

Fish make up some 90% of the blacktip shark's diet.[20] A wide variety of fish have been recorded as prey for this species: sardines, herring, anchovies, ladyfish, sea catfish, cornetfish, flatfish, threadfins, mullet, mackerel, jacks, groupers, snook, porgies, mojarras, emperors, grunts, butterfish, tilapia, triggerfish, boxfish, and porcupinefish. They also feed on rays and skates, as well as smaller sharks such as smoothhounds and sharpnose sharks. Crustaceans and cephalopods are occasionally taken.[1] In the Gulf of Mexico, the most important prey of the blacktip shark is the Gulf menhaden (Brevoortia patronus), followed by the Atlantic croaker (Micropogonias undulatus).[20] Off South Africa, jacks and herring are the most important prey.[21] Hunting peaks at dawn and dusk.[20] The excitability and sociability of blacktip sharks makes them prone to feeding frenzies when large quantities of food are suddenly available, such as when fishing vessels dump their refuse overboard.[1]

Life history

As with other requiem sharks, the blacktip shark exhibits vivipary. Females typically give birth to four to seven (range one to 10) pups every other year, making use of shallow coastal nurseries that offer plentiful food and fewer predators.[1] Known nurseries include Pine Island Sound, Terra Ceia Bay, and Yankeetown along the Gulf Coast of Florida, Bulls Bay on the coast of South Carolina, and Pontal do Paraná on the coast of Brazil.[22][23] Although adult blacktip sharks are highly mobile and disperse over long distances, they are philopatric and return to their original nursery areas to give birth. This results in a series of genetically distinct breeding stocks that overlap in geographic range.[22][24]

Mating occurs from spring to early summer, and the young are born around the same time the following year after a gestation period of 10–12 months.[1] Females have one functional ovary and two functional uteri; each uterus is separated into compartments with a single embryo inside each.[25] The embryos are initially sustained by a yolk sac; in the 10th or 11th week of gestation, when the embryo measures 18–19 cm long (7.1–7.5 in), the supply of yolk is exhausted and the yolk sac develops into a placental connection that sustains the embryo until birth.[11] The length at birth is 55–60 cm (22–24 in) off the eastern United States and 61–65 cm (24–26 in) off North Africa.[11][25] The mortality rate in the first 15 months of life is 61–91%, with major threats being predation and starvation.[26] The young remain in the nurseries until their first fall, when they migrate to their wintering grounds.[11]

The growth rate of this species slows with age: 25–30 cm (9.8–11.8 in) in the first six months, then 20 cm (7.9 in) a year until the second year, then 10 cm (3.9 in) a year until maturation, then 5 cm (2.0 in) a year for adults.[27][28] The size at maturity varies geographically: males and females mature at 1.4–1.5 m (4.6–4.9 ft) and 1.6 m (5.2 ft), respectively, in the northeastern Atlantic,[11] 1.3–1.4 m (4.3–4.6 ft) and 1.5–1.6 m (4.9–5.2 ft), respectively, in the Gulf of Mexico,[27][29] 1.5 and 1.6 m (4.9 and 5.2 ft) respectively off South Africa,[30] and 1.7 and 1.8 m (5.6 and 5.9 ft), respectively, off North Africa.[25] The age at maturation is 4–5 years for males and 7–8 years for females.[27][29] The lifespan is at least 12 years.[1]

In 2007, a 9-year-old female blacktip shark at the Virginia Aquarium and Marine Science Center was found to be pregnant with a single near-term female pup, despite having never mated with a male. Genetic analysis confirmed that her offspring was the product of automictic parthenogenesis, a form of asexual reproduction in which an ovum merges with a polar body to form a zygote without fertilization. Along with an earlier case of parthenogenesis in the bonnethead (Sphyrna tiburo), this event suggests that asexual reproduction may be more widespread in sharks than previously thought.[31]

Human interactions

The blacktip shark usually poses little danger to divers.

Blacktip sharks showing curiosity towards divers has been reported, but they remain at a safe distance. Under most circumstances, these timid sharks are not regarded as highly dangerous to humans. However, they may become aggressive in the presence of food, and their size and speed invite respect.[1] As of 2008, the International Shark Attack File lists 28 unprovoked attacks (one fatal) and 13 provoked attacks by this species.[32] Blacktip sharks are responsible annually for 16% of the shark attacks around Florida. Most attacks by this species result in only minor wounds.[2]

As one of the most common large sharks in coastal waters, the blacktip shark is caught in large numbers by commercial fisheries throughout the world, using longlines, fixed-bottom nets, bottom trawls, and hook-and-line. The meat is of high quality and marketed fresh, frozen, or dried and salted. In addition, the fins are used for shark fin soup, the skin for leather, the liver oil for vitamins, and the carcasses for fishmeal.[1] Blacktip sharks are one of the most important species to the northwestern Atlantic shark fishery, second only to the sandbar shark (C. plumbeus). The flesh is considered superior to that of the sandbar shark, resulting in the sandbar and other requiem shark species being sold under the name "blacktip shark" in the United States. The blacktip shark is also very significant to Indian and Mexican fisheries, and is caught in varying numbers by fisheries in the Mediterranean and South China Seas, and off northern Australia.[28]

The blacktip shark is popular with recreational anglers in Florida, the Caribbean, and South Africa. It is listed as a game fish by the International Game Fish Association. Once hooked, this species is a strong, steady fighter that sometimes jumps out of the water.[2] Since 1995, the number of blacktip sharks taken by recreational anglers in the United States has approached or surpassed the number taken by commercial fishing.[28] The International Union for Conservation of Nature has assessed the blacktip shark as Near Threatened, as its low reproductive rate renders it vulnerable to overfishing.[33] The United States and Australia are the only two countries that manage fisheries catching blacktip sharks. In both cases, regulation occurs under umbrella management schemes for multiple shark species, such as that for the large coastal sharks category of the US National Marine Fisheries Service Atlantic shark Fisheries Management Plan. No conservation plans specifically for this species have been implemented.[28]

References

  1. ^ a b c d e f g h i j k l m n o Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Rome: Food and Agricultural Organization. pp. 481–483. ISBN 92-5-101384-5. 
  2. ^ a b c d e f Curtis, T. Biological Profiles: Blacktip Shark. Florida Museum of Natural History Ichthyology Department. Retrieved on April 27, 2009.
  3. ^ a b c d Ebert, D.A. (2003). Sharks, Rays, and Chimaeras of California. London: University of California Press. pp. 156–157. ISBN 0-520-23484-7. 
  4. ^ a b c Froese, Rainer and Pauly, Daniel, eds. (2009). "Carcharhinus limbatus" in FishBase. April 2009 version.
  5. ^ Dosay-Akbulut, M. (2008). "The phylogenetic relationship within the genus Carcharhinus". Comptes Rendus Biologies. 331 (7): 500–509. doi:10.1016/j.crvi.2008.04.001. PMID 18558373. 
  6. ^ Keeney, D.B. & Heist, E.J. (October 2006). "Worldwide phylogeography of the blacktip shark (Carcharhinus limbatus) inferred from mitochondrial DNA reveals isolation of western Atlantic populations coupled with recent Pacific dispersal". Molecular Ecology. 15 (12): 3669–3679. doi:10.1111/j.1365-294X.2006.03036.x. PMID 17032265. 
  7. ^ Benson. R.N., ed. (1998). Geology and Paleontology of the Lower Miocene Pollack Farm Fossil Site, Delaware: Delaware Geological Survey Special Publication No. 21. Delaware Natural History Survey. pp. 133–139. 
  8. ^ Brown, R.C. (2008). Florida's Fossils: Guide to Location, Identification, and Enjoyment (third ed.). Pineapple Press Inc. p. 100. ISBN 1-56164-409-9. 
  9. ^ Martin, R.A. Albinism in Sharks. ReefQuest Centre for Shark Research. Retrieved on April 28, 2009.
  10. ^ Yano, Kazunari; Morrissey, John F. (1999-06-01). "Confirmation of blacktip shark,Carcharhinus limbatus, in the Ryukyu Islands and notes on possible absence ofC. melanopterus in Japanese waters". Ichthyological Research. 46 (2): 193–198. doi:10.1007/BF02675438. ISSN 1341-8998. 
  11. ^ a b c d e Castro, J.I. (November 1996). "Biology of the blacktip shark, Carcharhinus limbatus, off the southeastern United States". Bulletin of Marine Science. 59 (3): 508–522. 
  12. ^ Heupel, M.R. & Simpfendorfer, C.A. (2005). "Quantitative analysis of aggregation behavior in juvenile blacktip sharks". Marine Biology. 147 (5): 1239–1249. doi:10.1007/s00227-005-0004-7. 
  13. ^ Heupel, M.R. & Hueter, R.E. (2002). "The importance of prey density in relation to the movement patterns of juvenile sharks within a coastal nursery area". Marine and Freshwater Research. 53 (2): 543–550. doi:10.1071/MF01132. 
  14. ^ Bullard, S.A.; Frasca, A. (Jr.) & Benz, G.W. (June 2000). "Skin Lesions Caused by Dermophthirius penneri (Monogenea: Microbothriidae) on Wild-Caught Blacktip Sharks (Carcharhinus limbatus)". Journal of Parasitology. 86 (3): 618–622. doi:10.1645/0022-3395(2000)086[0618:SLCBDP]2.0.CO;2. PMID 10864264. 
  15. ^ Bullard, S.A.; Benz, G.W. & Braswell, J.S. (2000). "Dionchus postoncomiracidia (Monogenea: Dionchidae) from the skin of blacktip sharks, Carcharhinus limbatus (Carcharhinidae)". Journal of Parasitology. 86 (2): 245–250. doi:10.1645/0022-3395(2000)086[0245:DPMDFT]2.0.CO;2. JSTOR 3284763. PMID 10780540. 
  16. ^ Rosa-Molinar, E. & Williams, C.S. (1983). "Larval nematodes (Philometridae) in granulomas in ovaries of blacktip sharks, Carcharhinus limbatus (Valenciennes)". Journal of Wildlife Diseases. 19 (3): 275–277. doi:10.7589/0090-3558-19.3.275. PMID 6644926. 
  17. ^ Riner, E.K. & Brijnnschweiler, J.M. (2003). "Do sharksuckers, Echeneis naucrates, induce jump behaviour in blacktip sharks, Carcharhinus limbatus?". Marine and Freshwater Behaviour and Physiology. 36 (2): 111–113. doi:10.1080/1023624031000119584. 
  18. ^ Brunnschweiler, J.M. (2005). "Water-escape velocities in jumping blacktip sharks". Journal of the Royal Society Interface. 2 (4): 389–391. doi:10.1098/rsif.2005.0047. PMC 1578268Freely accessible. PMID 16849197. 
  19. ^ Ritter, E.K. & Godknecht, A.J. (February 1, 2000). Ross, S. T., ed. "Agonistic Displays in the Blacktip Shark (Carcharhinus limbatus)". Copeia. 2000 (1): 282–284. doi:10.1643/0045-8511(2000)2000[0282:ADITBS]2.0.CO;2. JSTOR 1448264. 
  20. ^ a b c Barry, K.P. (2002). Feeding habits of blacktip sharks, Carcharhinus limbatus, and Atlantic sharpnose sharks, Rhizoprionodon terraenovae, in Louisiana coastal waters. MS thesis, Louisiana State University, Baton Rouge.
  21. ^ Dudley, S.F.J. & Cliff, G. (1993). "Sharks caught in the protective gill nets off Natal, South Africa. 7. The blacktip shark Carcharhinus limbatus (Valenciennes)". African Journal of Marine Science. 13: 237–254. doi:10.2989/025776193784287356. 
  22. ^ a b Keeney, D.B.; Heupel, M.; Hueter, R.E. & Heist, E.J. (2003). "Genetic heterogeneity among blacktip shark, Carcharhinus limbatus, continental nurseries along the U.S. Atlantic and Gulf of Mexico". Marine Biology. 143 (6): 1039–1046. doi:10.1007/s00227-003-1166-9. 
  23. ^ Bornatowski, H. (2008). "A parturition and nursery area for Carcharhinus limbatus (Elasmobranchii, Carcharhinidae) off the coast of Paraná, Brazil". Brazilian Journal of Oceanography. 56 (4): 317–319. doi:10.1590/s1679-87592008000400008. 
  24. ^ Keeney, D.B.; Heupel, M.R.; Hueter, R.E. & Heist, E.J. (2005). "Microsatellite and mitochondrial DNA analyses of the genetic structure of blacktip shark (Carcharhinus limbatus) nurseries in the northwestern Atlantic, Gulf of Mexico, and Caribbean Sea". Molecular Ecology. 14 (7): 1911–1923. doi:10.1111/j.1365-294X.2005.02549.x. PMID 15910315. 
  25. ^ a b c Capapé, C.H.; Seck, A.A.; Diatta, Y.; Reynaud, C.H.; Hemida, F. & Zaouali, J. (2004). "Reproductive biology of the blacktip shark, Carcharhinus limbatus (Chondrichthyes: Carcharhinidae) off West and North African Coasts" (PDF). Cybium. 28 (4): 275–284. 
  26. ^ Heupel, M.R. & Simpfendorfer, C.A. (2002). "Estimation of mortality of juvenile blacktip sharks, Carcharhinus limbatus, within a nursery area using telemetry data". Canadian Journal of Fisheries and Aquatic Sciences. 59 (4): 624–632. doi:10.1139/f02-036. 
  27. ^ a b c Branstetter, S. (December 9, 1987). "Age and Growth Estimates for Blacktip, Carcharhinus limbatus, and Spinner, C. brevipinna, Sharks from the Northwestern Gulf of Mexico". Copeia. American Society of Ichthyologists and Herpetologists. 1987 (4): 964–974. doi:10.2307/1445560. JSTOR 1445560. 
  28. ^ a b c d Fowler, S.L.; Cavanagh, R.D.; Camhi, M.; Burgess, G.H.; Cailliet, G.M.; Fordham, S.V.; Simpfendorfer, C.A. & Musick, J.A. (2005). Sharks, Rays and Chimaeras: The Status of the Chondrichthyan Fishes. International Union for Conservation of Nature and Natural Resources. pp. 106–109, 293–295. ISBN 2-8317-0700-5. 
  29. ^ a b Killam, K.A. & Parsons, G.R. (May 1989). "Age and Growth of the Blacktip Shark, Carcharhinus limbatus, near Tampa Bay" (PDF). Florida Fishery Bulletin. 87: 845–857. 
  30. ^ Wintner, S.P. & Cliff, G. (1996). "Age and growth determination of the blacktip shark, Carcharhinus limbatus, from the east coast of South Africa" (PDF). Fishery Bulletin. 94 (1): 135–144. 
  31. ^ Chapman, D.D.; Firchau, B. & Shivji, M.S. (2008). "Parthenogenesis in a large-bodied requiem shark, the blacktip Carcharhinus limbatus". Journal of Fish Biology. 73 (6): 1473–1477. doi:10.1111/j.1095-8649.2008.02018.x. 
  32. ^ ISAF Statistics on Attacking Species of Shark. International Shark Attack File, Florida Museum of Natural History, University of Florida. Retrieved on April 22, 2009.
  33. ^ Musick, J.A.; Fowler, S. (2000). "Carcharhinus limbatus". IUCN Red List of Threatened Species. Version 2007. International Union for Conservation of Nature. Retrieved April 27, 2009. 
source: http://en.wikipedia.org/wiki/Blacktip_shark

Blacktip Shark 1

Blacktip Shark by Inked Animal

Blacktip Shark | Carcharhinus limbatus

 


Blacktip Shark info via Wikipedia:

Not to be confused with the blacktip reef shark, Carcharhinus melanopterus.
Blacktip shark
Carcharhinus limbatus (2).jpg
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Carcharhiniformes
Family: Carcharhinidae
Genus: Carcharhinus
Species: C. limbatus
Binomial name
Carcharhinus limbatus
(J. P. Müller & Henle, 1839)
Carcharhinus limbatus distmap.png
Range of the blacktip shark
Synonyms

Carcharias abbreviatus Klunzinger, 1871
Carcharias aethalorus Jordan & Gilbert, 1882
Carcharias ehrenbergi Klunzinger, 1871
Carcharias maculipinna Günther, 1868
Carcharias microps Lowe, 1841
Carcharias muelleri Steindachner, 1867
Carcharias phorcys Jordan & Evermann, 1903
Carcharias pleurotaenia Bleeker, 1852
Carcharhinus natator Meek & Hildebrand, 1923

The blacktip shark (Carcharhinus limbatus) is a species of requiem shark, and part of the family Carcharhinidae. It is common to coastal tropical and subtropical waters around the world, including brackish habitats. Genetic analyses have revealed substantial variation within this species, with populations from the western Atlantic Ocean isolated and distinct from those in the rest of its range. The blacktip shark has a stout, fusiform body with a pointed snout, long gill slits, and no ridge between the dorsal fins. Most individuals have black tips or edges on the pectoral, dorsal, pelvic, and caudal fins. It usually attains a length of 1.5 m (4.9 ft).

Swift, energetic piscivores, blacktip sharks are known to make spinning leaps out of the water while attacking schools of small fish. Their demeanor has been described as "timid" compared to other large requiem sharks. Both juveniles and adults form groups of varying size. Like other members of its family, the blacktip shark is viviparous; females bear one to 10 pups every other year. Young blacktip sharks spend the first months of their lives in shallow nurseries, and grown females return to the nurseries where they were born to give birth themselves. In the absence of males, females are also capable of asexual reproduction.

Normally wary of humans, blacktip sharks can become aggressive in the presence of food and have been responsible for a number of attacks on people. This species is of importance to both commercial and recreational fisheries across many parts of its range, with its meat, skin, fins, and liver oil used. It has been assessed as Near Threatened by the IUCN, on the basis of its low reproductive rate and high value to fishers.

Taxonomy

The blacktip shark was first described by French zoologist Achille Valenciennes as Carcharias (Prionodon) limbatus in Johannes Müller and Friedrich Henle's 1839 Systematische Beschreibung der Plagiostomen. The type specimens were two individuals caught off Martinique, both of which have since been lost. Later authors moved this species to the genus Carcharhinus.[1][2] The specific epithet limbatus is Latin for "bordered", referring to the black edges of this shark's fins.[3] Other common names used for the blacktip shark include blackfin shark, blacktip whaler, common or small blacktip shark, grey shark, and spotfin ground shark.[4]

Phylogeny and evolution

The closest relatives of the blacktip shark were originally thought to be the graceful shark (C. amblyrhynchoides) and the spinner shark (C. brevipinna), due to similarities in morphology and behavior. However, this interpretation has not been borne out by studies of mitochondrial and ribosomal DNA, which instead suggest affinity with the blacknose shark (C. acronotus). More work is required to fully resolve the relationship between the blacktip shark and other Carcharhinus species.[5]

Analysis of mitochondrial DNA has also revealed two distinct lineages within this species, one occupying the western Atlantic and the other occupying the eastern Atlantic, Indian, and Pacific Oceans. This suggests that Indo-Pacific blacktip sharks are descended from those in the eastern Atlantic, while the western Atlantic sharks became isolated by the widening Atlantic Ocean on one side and the formation of the Isthmus of Panama on the other. Blacktip sharks from these two regions differ in morphology, coloration, and life history characteristics, and the eastern Atlantic lineage may merit species status.[6] Fossil teeth belonging to this species have been found in Early Miocene (23–16 Ma) deposits in Delaware and Florida.[7][8]

Description

The blacktip shark has a robust, streamlined body with a long, pointed snout and relatively small eyes. The five pairs of gill slits are longer than those of similar requiem shark species.[1] The jaws contain 15 tooth rows on either side, with two symphysial teeth (at the jaw midline) in the upper jaw and one symphysial tooth in the lower jaw. The teeth are broad-based with a high, narrow cusp and serrated edges.[2] The first dorsal fin is tall and falcate (sickle-shaped) with a short free rear tip; no ridge runs between the first and second dorsal fins. The large pectoral fins are falcate and pointed.[1]

The coloration is gray to brown above and white below, with a conspicuous white stripe running along the sides. The pectoral fins, second dorsal fin, and the lower lobe of the caudal fin usually have black tips. The pelvic fins and rarely the anal fin may also be black-tipped. The first dorsal fin and the upper lobe of the caudal fin typically have black edges.[1] Some larger individuals have unmarked or nearly unmarked fins.[3] Blacktip sharks can temporarily lose almost all their colors during blooms, or "whitings", of coccolithophores.[9] This species attains a maximum known length of 2.8 m (9.2 ft), though 1.5 m (4.9 ft) is more typical, and a maximum known weight of 123 kg (271 lb).[4]

Distribution and habitat

A blacktip shark swimming in murky water off Oahu, Hawaii

The blacktip shark has a worldwide distribution in tropical and subtropical waters. In the Atlantic, it is found from Massachusetts to Brazil, including the Gulf of Mexico and the Caribbean Sea, and from the Mediterranean Sea, Madeira, and the Canary Islands to the Democratic Republic of the Congo. It occurs all around the periphery of the Indian Ocean, from South Africa and Madagascar to the Arabian Peninsula and the Indian subcontinent, to Southeast Asia. In the western Pacific, it is found from the Ryukyu Islands of Japan[10] to northern Australia, including southern China, the Philippines and Indonesia. In the eastern Pacific, it occurs from Baja California to Peru. It has also been reported at a number of Pacific islands, including New Caledonia, Tahiti, the Marquesas, Hawaii, Revillagigedo, and the Galápagos.[1]

Most blacktip sharks are found in water less than 30 m (98 ft) deep over continental and insular shelves, though they may dive to 64 m (210 ft).[4] Favored habitats are muddy bays, island lagoons, and the drop-offs near coral reefs; they are also tolerant of low salinity and enter estuaries and mangrove swamps. Although an individual may be found some distance offshore, blacktip sharks do not inhabit oceanic waters.[1] Seasonal migration has been documented for the population off the east coast of the United States, moving north to North Carolina in the summer and south to Florida in the winter.[11]

Biology and ecology

The blacktip shark is an extremely fast, energetic predator that is usually found in groups of varying size.[3] Segregation by sex and age does not occur; adult males and nonpregnant females are found apart from pregnant females, and both are separated from juveniles.[1] In Terra Ceia Bay, Florida, a nursery area for this species, juvenile blacktips form aggregations during the day and disperse at night. They aggregate most strongly in the early summer when the sharks are youngest, suggesting that they are seeking refuge from predators (mostly larger sharks) in numbers.[12] Predator avoidance may also be the reason why juvenile blacktips do not congregate in the areas of highest prey density in the bay.[13] Adults have no known predators.[2] Known parasites of the blacktip shark include the copepods Pandarus sinuatus and P. smithii, and the monogeneans Dermophthirius penneri and Dionchus spp., which attach the shark's skin.[2][14][15] This species is also parasitized by nematodes in the family Philometridae, which infest the ovaries.[16]

Behaviour

Blacktip sharks are social and usually found in groups.

Like the spinner shark, the blacktip shark is known to leap out of the water and spin three or four times about its axis before landing. Some of these jumps are the end product of feeding runs, in which the shark corkscrews vertically through schools of small fish and its momentum launches it into the air.[3] Observations in the Bahamas suggest that blacktip sharks may also jump out of the water to dislodge attached sharksuckers (Echeneis naucrates), which irritate the shark's skin and compromise its hydrodynamic shape.[17] The speed attained by the shark during these jumps has been estimated to average 6.3 m/s (21 ft/s).[18]

Blacktip sharks have a timid disposition and consistently lose out to Galapagos sharks (C. galapagensis) and silvertip sharks (C. albimarginatus) of equal size when competing for food.[1] If threatened or challenged, they may perform an agonistic display: the shark swims towards the threat and then turns away, while rolling from side to side, lowering its pectoral fins, tilting its head and tail upwards, and making sideways biting motions. The entire sequence lasts around 25 seconds. This behavior is similar to the actions of a shark attempting to move a sharksucker; one of these behaviors possibly is derived from the other.[19]

Feeding

Fish make up some 90% of the blacktip shark's diet.[20] A wide variety of fish have been recorded as prey for this species: sardines, herring, anchovies, ladyfish, sea catfish, cornetfish, flatfish, threadfins, mullet, mackerel, jacks, groupers, snook, porgies, mojarras, emperors, grunts, butterfish, tilapia, triggerfish, boxfish, and porcupinefish. They also feed on rays and skates, as well as smaller sharks such as smoothhounds and sharpnose sharks. Crustaceans and cephalopods are occasionally taken.[1] In the Gulf of Mexico, the most important prey of the blacktip shark is the Gulf menhaden (Brevoortia patronus), followed by the Atlantic croaker (Micropogonias undulatus).[20] Off South Africa, jacks and herring are the most important prey.[21] Hunting peaks at dawn and dusk.[20] The excitability and sociability of blacktip sharks makes them prone to feeding frenzies when large quantities of food are suddenly available, such as when fishing vessels dump their refuse overboard.[1]

Life history

As with other requiem sharks, the blacktip shark exhibits vivipary. Females typically give birth to four to seven (range one to 10) pups every other year, making use of shallow coastal nurseries that offer plentiful food and fewer predators.[1] Known nurseries include Pine Island Sound, Terra Ceia Bay, and Yankeetown along the Gulf Coast of Florida, Bulls Bay on the coast of South Carolina, and Pontal do Paraná on the coast of Brazil.[22][23] Although adult blacktip sharks are highly mobile and disperse over long distances, they are philopatric and return to their original nursery areas to give birth. This results in a series of genetically distinct breeding stocks that overlap in geographic range.[22][24]

Mating occurs from spring to early summer, and the young are born around the same time the following year after a gestation period of 10–12 months.[1] Females have one functional ovary and two functional uteri; each uterus is separated into compartments with a single embryo inside each.[25] The embryos are initially sustained by a yolk sac; in the 10th or 11th week of gestation, when the embryo measures 18–19 cm long (7.1–7.5 in), the supply of yolk is exhausted and the yolk sac develops into a placental connection that sustains the embryo until birth.[11] The length at birth is 55–60 cm (22–24 in) off the eastern United States and 61–65 cm (24–26 in) off North Africa.[11][25] The mortality rate in the first 15 months of life is 61–91%, with major threats being predation and starvation.[26] The young remain in the nurseries until their first fall, when they migrate to their wintering grounds.[11]

The growth rate of this species slows with age: 25–30 cm (9.8–11.8 in) in the first six months, then 20 cm (7.9 in) a year until the second year, then 10 cm (3.9 in) a year until maturation, then 5 cm (2.0 in) a year for adults.[27][28] The size at maturity varies geographically: males and females mature at 1.4–1.5 m (4.6–4.9 ft) and 1.6 m (5.2 ft), respectively, in the northeastern Atlantic,[11] 1.3–1.4 m (4.3–4.6 ft) and 1.5–1.6 m (4.9–5.2 ft), respectively, in the Gulf of Mexico,[27][29] 1.5 and 1.6 m (4.9 and 5.2 ft) respectively off South Africa,[30] and 1.7 and 1.8 m (5.6 and 5.9 ft), respectively, off North Africa.[25] The age at maturation is 4–5 years for males and 7–8 years for females.[27][29] The lifespan is at least 12 years.[1]

In 2007, a 9-year-old female blacktip shark at the Virginia Aquarium and Marine Science Center was found to be pregnant with a single near-term female pup, despite having never mated with a male. Genetic analysis confirmed that her offspring was the product of automictic parthenogenesis, a form of asexual reproduction in which an ovum merges with a polar body to form a zygote without fertilization. Along with an earlier case of parthenogenesis in the bonnethead (Sphyrna tiburo), this event suggests that asexual reproduction may be more widespread in sharks than previously thought.[31]

Human interactions

The blacktip shark usually poses little danger to divers.

Blacktip sharks showing curiosity towards divers has been reported, but they remain at a safe distance. Under most circumstances, these timid sharks are not regarded as highly dangerous to humans. However, they may become aggressive in the presence of food, and their size and speed invite respect.[1] As of 2008, the International Shark Attack File lists 28 unprovoked attacks (one fatal) and 13 provoked attacks by this species.[32] Blacktip sharks are responsible annually for 16% of the shark attacks around Florida. Most attacks by this species result in only minor wounds.[2]

As one of the most common large sharks in coastal waters, the blacktip shark is caught in large numbers by commercial fisheries throughout the world, using longlines, fixed-bottom nets, bottom trawls, and hook-and-line. The meat is of high quality and marketed fresh, frozen, or dried and salted. In addition, the fins are used for shark fin soup, the skin for leather, the liver oil for vitamins, and the carcasses for fishmeal.[1] Blacktip sharks are one of the most important species to the northwestern Atlantic shark fishery, second only to the sandbar shark (C. plumbeus). The flesh is considered superior to that of the sandbar shark, resulting in the sandbar and other requiem shark species being sold under the name "blacktip shark" in the United States. The blacktip shark is also very significant to Indian and Mexican fisheries, and is caught in varying numbers by fisheries in the Mediterranean and South China Seas, and off northern Australia.[28]

The blacktip shark is popular with recreational anglers in Florida, the Caribbean, and South Africa. It is listed as a game fish by the International Game Fish Association. Once hooked, this species is a strong, steady fighter that sometimes jumps out of the water.[2] Since 1995, the number of blacktip sharks taken by recreational anglers in the United States has approached or surpassed the number taken by commercial fishing.[28] The International Union for Conservation of Nature has assessed the blacktip shark as Near Threatened, as its low reproductive rate renders it vulnerable to overfishing.[33] The United States and Australia are the only two countries that manage fisheries catching blacktip sharks. In both cases, regulation occurs under umbrella management schemes for multiple shark species, such as that for the large coastal sharks category of the US National Marine Fisheries Service Atlantic shark Fisheries Management Plan. No conservation plans specifically for this species have been implemented.[28]

References

  1. ^ a b c d e f g h i j k l m n o Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Rome: Food and Agricultural Organization. pp. 481–483. ISBN 92-5-101384-5. 
  2. ^ a b c d e f Curtis, T. Biological Profiles: Blacktip Shark. Florida Museum of Natural History Ichthyology Department. Retrieved on April 27, 2009.
  3. ^ a b c d Ebert, D.A. (2003). Sharks, Rays, and Chimaeras of California. London: University of California Press. pp. 156–157. ISBN 0-520-23484-7. 
  4. ^ a b c Froese, Rainer and Pauly, Daniel, eds. (2009). "Carcharhinus limbatus" in FishBase. April 2009 version.
  5. ^ Dosay-Akbulut, M. (2008). "The phylogenetic relationship within the genus Carcharhinus". Comptes Rendus Biologies. 331 (7): 500–509. doi:10.1016/j.crvi.2008.04.001. PMID 18558373. 
  6. ^ Keeney, D.B. & Heist, E.J. (October 2006). "Worldwide phylogeography of the blacktip shark (Carcharhinus limbatus) inferred from mitochondrial DNA reveals isolation of western Atlantic populations coupled with recent Pacific dispersal". Molecular Ecology. 15 (12): 3669–3679. doi:10.1111/j.1365-294X.2006.03036.x. PMID 17032265. 
  7. ^ Benson. R.N., ed. (1998). Geology and Paleontology of the Lower Miocene Pollack Farm Fossil Site, Delaware: Delaware Geological Survey Special Publication No. 21. Delaware Natural History Survey. pp. 133–139. 
  8. ^ Brown, R.C. (2008). Florida's Fossils: Guide to Location, Identification, and Enjoyment (third ed.). Pineapple Press Inc. p. 100. ISBN 1-56164-409-9. 
  9. ^ Martin, R.A. Albinism in Sharks. ReefQuest Centre for Shark Research. Retrieved on April 28, 2009.
  10. ^ Yano, Kazunari; Morrissey, John F. (1999-06-01). "Confirmation of blacktip shark,Carcharhinus limbatus, in the Ryukyu Islands and notes on possible absence ofC. melanopterus in Japanese waters". Ichthyological Research. 46 (2): 193–198. doi:10.1007/BF02675438. ISSN 1341-8998. 
  11. ^ a b c d e Castro, J.I. (November 1996). "Biology of the blacktip shark, Carcharhinus limbatus, off the southeastern United States". Bulletin of Marine Science. 59 (3): 508–522. 
  12. ^ Heupel, M.R. & Simpfendorfer, C.A. (2005). "Quantitative analysis of aggregation behavior in juvenile blacktip sharks". Marine Biology. 147 (5): 1239–1249. doi:10.1007/s00227-005-0004-7. 
  13. ^ Heupel, M.R. & Hueter, R.E. (2002). "The importance of prey density in relation to the movement patterns of juvenile sharks within a coastal nursery area". Marine and Freshwater Research. 53 (2): 543–550. doi:10.1071/MF01132. 
  14. ^ Bullard, S.A.; Frasca, A. (Jr.) & Benz, G.W. (June 2000). "Skin Lesions Caused by Dermophthirius penneri (Monogenea: Microbothriidae) on Wild-Caught Blacktip Sharks (Carcharhinus limbatus)". Journal of Parasitology. 86 (3): 618–622. doi:10.1645/0022-3395(2000)086[0618:SLCBDP]2.0.CO;2. PMID 10864264. 
  15. ^ Bullard, S.A.; Benz, G.W. & Braswell, J.S. (2000). "Dionchus postoncomiracidia (Monogenea: Dionchidae) from the skin of blacktip sharks, Carcharhinus limbatus (Carcharhinidae)". Journal of Parasitology. 86 (2): 245–250. doi:10.1645/0022-3395(2000)086[0245:DPMDFT]2.0.CO;2. JSTOR 3284763. PMID 10780540. 
  16. ^ Rosa-Molinar, E. & Williams, C.S. (1983). "Larval nematodes (Philometridae) in granulomas in ovaries of blacktip sharks, Carcharhinus limbatus (Valenciennes)". Journal of Wildlife Diseases. 19 (3): 275–277. doi:10.7589/0090-3558-19.3.275. PMID 6644926. 
  17. ^ Riner, E.K. & Brijnnschweiler, J.M. (2003). "Do sharksuckers, Echeneis naucrates, induce jump behaviour in blacktip sharks, Carcharhinus limbatus?". Marine and Freshwater Behaviour and Physiology. 36 (2): 111–113. doi:10.1080/1023624031000119584. 
  18. ^ Brunnschweiler, J.M. (2005). "Water-escape velocities in jumping blacktip sharks". Journal of the Royal Society Interface. 2 (4): 389–391. doi:10.1098/rsif.2005.0047. PMC 1578268Freely accessible. PMID 16849197. 
  19. ^ Ritter, E.K. & Godknecht, A.J. (February 1, 2000). Ross, S. T., ed. "Agonistic Displays in the Blacktip Shark (Carcharhinus limbatus)". Copeia. 2000 (1): 282–284. doi:10.1643/0045-8511(2000)2000[0282:ADITBS]2.0.CO;2. JSTOR 1448264. 
  20. ^ a b c Barry, K.P. (2002). Feeding habits of blacktip sharks, Carcharhinus limbatus, and Atlantic sharpnose sharks, Rhizoprionodon terraenovae, in Louisiana coastal waters. MS thesis, Louisiana State University, Baton Rouge.
  21. ^ Dudley, S.F.J. & Cliff, G. (1993). "Sharks caught in the protective gill nets off Natal, South Africa. 7. The blacktip shark Carcharhinus limbatus (Valenciennes)". African Journal of Marine Science. 13: 237–254. doi:10.2989/025776193784287356. 
  22. ^ a b Keeney, D.B.; Heupel, M.; Hueter, R.E. & Heist, E.J. (2003). "Genetic heterogeneity among blacktip shark, Carcharhinus limbatus, continental nurseries along the U.S. Atlantic and Gulf of Mexico". Marine Biology. 143 (6): 1039–1046. doi:10.1007/s00227-003-1166-9. 
  23. ^ Bornatowski, H. (2008). "A parturition and nursery area for Carcharhinus limbatus (Elasmobranchii, Carcharhinidae) off the coast of Paraná, Brazil". Brazilian Journal of Oceanography. 56 (4): 317–319. doi:10.1590/s1679-87592008000400008. 
  24. ^ Keeney, D.B.; Heupel, M.R.; Hueter, R.E. & Heist, E.J. (2005). "Microsatellite and mitochondrial DNA analyses of the genetic structure of blacktip shark (Carcharhinus limbatus) nurseries in the northwestern Atlantic, Gulf of Mexico, and Caribbean Sea". Molecular Ecology. 14 (7): 1911–1923. doi:10.1111/j.1365-294X.2005.02549.x. PMID 15910315. 
  25. ^ a b c Capapé, C.H.; Seck, A.A.; Diatta, Y.; Reynaud, C.H.; Hemida, F. & Zaouali, J. (2004). "Reproductive biology of the blacktip shark, Carcharhinus limbatus (Chondrichthyes: Carcharhinidae) off West and North African Coasts" (PDF). Cybium. 28 (4): 275–284. 
  26. ^ Heupel, M.R. & Simpfendorfer, C.A. (2002). "Estimation of mortality of juvenile blacktip sharks, Carcharhinus limbatus, within a nursery area using telemetry data". Canadian Journal of Fisheries and Aquatic Sciences. 59 (4): 624–632. doi:10.1139/f02-036. 
  27. ^ a b c Branstetter, S. (December 9, 1987). "Age and Growth Estimates for Blacktip, Carcharhinus limbatus, and Spinner, C. brevipinna, Sharks from the Northwestern Gulf of Mexico". Copeia. American Society of Ichthyologists and Herpetologists. 1987 (4): 964–974. doi:10.2307/1445560. JSTOR 1445560. 
  28. ^ a b c d Fowler, S.L.; Cavanagh, R.D.; Camhi, M.; Burgess, G.H.; Cailliet, G.M.; Fordham, S.V.; Simpfendorfer, C.A. & Musick, J.A. (2005). Sharks, Rays and Chimaeras: The Status of the Chondrichthyan Fishes. International Union for Conservation of Nature and Natural Resources. pp. 106–109, 293–295. ISBN 2-8317-0700-5. 
  29. ^ a b Killam, K.A. & Parsons, G.R. (May 1989). "Age and Growth of the Blacktip Shark, Carcharhinus limbatus, near Tampa Bay" (PDF). Florida Fishery Bulletin. 87: 845–857. 
  30. ^ Wintner, S.P. & Cliff, G. (1996). "Age and growth determination of the blacktip shark, Carcharhinus limbatus, from the east coast of South Africa" (PDF). Fishery Bulletin. 94 (1): 135–144. 
  31. ^ Chapman, D.D.; Firchau, B. & Shivji, M.S. (2008). "Parthenogenesis in a large-bodied requiem shark, the blacktip Carcharhinus limbatus". Journal of Fish Biology. 73 (6): 1473–1477. doi:10.1111/j.1095-8649.2008.02018.x. 
  32. ^ ISAF Statistics on Attacking Species of Shark. International Shark Attack File, Florida Museum of Natural History, University of Florida. Retrieved on April 22, 2009.
  33. ^ Musick, J.A.; Fowler, S. (2000). "Carcharhinus limbatus". IUCN Red List of Threatened Species. Version 2007. International Union for Conservation of Nature. Retrieved April 27, 2009. 
source: http://en.wikipedia.org/wiki/Blacktip_shark

Gafftopsail Catfish 2


Gafftopsail Catfish 2 by Inked Animal
Gafftopsail Catfish | Bagre marinus

 This Gyotaku deserves to be on a chinese restaurant’s wall.  Its very asian looking with the extremely falcate fins.  This animal was caught by either Adam or myself on a fishing trip to Matagorda Bay, one of our usual stomping grounds and sources for much of our saltwater material.  It is an interesting print, and misleading categorization, being that it doesn’t have scales.  Many catfish don’t have scales, but smooth skin which comes out in this print in an interesting way. Notice the wrinkles and paper creases.  Also, the long “swoop” from its chin back is the very long barbel that is covered in essentially taste buds.  Its what this animal uses to sense food.  If you like cats, make sure you check out Gafftop Catfish, Hardhead Catfish, and Hardhead Catfish – head.

 

 

 

 

 

 


 

Gafftopsail Catfish info via wikipedia:

Gafftopsail catfish
Bagre marinus (line art).jpg
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Ariidae
Genus: Bagre
Species: B. marinus
Binomial name
Bagre marinus
(Mitchill, 1815)
Synonyms[2]
  • Silurus marinus Mitchill, 1815
  • Felichthys marinus (Mitchill, 1815)
  • Galeichthys blochii Valenciennes, 1840
  • Galeichthys parrae Valenciennes, 1840
  • Galeichthys bahiensis Castelnau, 1855
  • Aelurichthys longispinis Günther, 1864

The gafftopsail catfish (Bagre marinus) is found in the waters of the western central Atlantic Ocean, as well as the Gulf of Mexico and the Caribbean Sea. It has long venomous spines which can cause painful wounds. It feeds on crustaceans and other fish. The male of the species fertilizes the eggs of the female, and broods them in his mouth until they hatch. The gafftopsail feeds throughout the water column. This fish is a common catch in the Southeastern US, although it may be found as far north as New York. In fishing, they are considered strong fighters. They are taken from piers, jetties, reefs, and the surf, as well as bottom fishing or flats fishing. They are caught with lures, cut bait, and shrimp, as well as soft plastics. Some fishermen use traps for catfish, which is regulated by some states.

Distribution

It lives on the Atlantic, Caribbean and Gulf of Mexico coastlines from Cape Cod to Brazil.[1] It is also found in brackish waters, including estuaries, lagoons, brackish seas, and mangroves. It is generally common to abundant in its range.[1]

Characteristics

The gafftopsail catfish is blue-grey to dark brown with a light grey belly. Its appearance is typical for a catfish except for the deeply forked tail and the venomous, serrated spines. It also has a little hump that looks somewhat like a wave. The typical length of a mature gafftopsail catfish is about 17 in (43 cm). The anal fin is a few inches anterior to the tail and is white or pale blue, with 22-28 rays on it and a high, anterior lobe.[3] The pelvic fin is 6–12 in (15–30 cm) anterior to the tail fin. The gafftopsail catfish has maxillary barbels and one pair of barbels on the chin. It resembles the hardhead catfish, but its dorsal spine has a distinctive fleshy extension (like the fore-and-aft topsail of a ship).

The primary food of juveniles is unidentifiable organic matter; the secondary food is fish, with smaller amounts from other trophic groups. Unlike many other catfish, which are primarily bottom feeders, the gafftopsail catfish feeds throughout the water column. It eats mostly crustaceans, including crabs, shrimp, and prawns (95% of the diet), but it will also eat worms, other invertebrates, and bony fishes (about 5% of the diet).[4] In addition to humans, predators of the gafftopsail catfish include the tiger shark and bull shark.

Gafftopsail catfish spawn over inshore mudflats during a relatively short time span (10 days) from May to August;[5] they are mouthbreeders. The eggs are about 1 in (2.5 cm) in diameter. Males keep up to 55 eggs in their mouths until they hatch. Young are about 5 cm (2 inches) long when they hatch, and the male may continue to brood them until they are up to 4 in (10 cm) long. The males do not feed while they are carrying the eggs or young.[6]

Fishing

The gafftopsail catfish is a common catch in the Southeastern United States, although it is also caught as far north as New York. They are taken from piers, jetties, reefs, and the surf, as well as bottom fishing or flats fishing. They are caught with lures such as plugs, spoons, spinners, cut bait, and shrimp, as well as soft plastic lure resembling shrimp, worms, and shad. They are attracted to the sound of struggling fish, like a popping cork creates. Catfish trapping is also used to capture them, but is regulated in some states. Catfish traps include “slat traps,” long wooden traps with an angled entrance, and wire hoop traps. Typical bait for these traps includes rotten cheese and dog food.

Gafftopsail catfish are good eating; the red lateral line should be removed to prevent “muddy taste”; however in Gafftopsail taken from southern Florida mangrove estuaries, this is seemingly unnecessary. The pectoral fins and dorsal fin contain venomous spines; care should be used when handling this fish.

Weight and length

Growth chart

The largest recorded weight for a gafftopsail catfish is 4.5 kg (9.9 lb)[7] and 69 cm (27 in) in length.[8] A more common weight and length of gafftopsails caught is 1–2 lb (450–910 g) and 12–16 in (30–41 cm).

As gafftopsail catfish grow longer, they increase in weight, but the relationship is not linear. The relationship between total length (L, in inches) and total weight (W, in pounds) for nearly all species of fish can be expressed by an equation of the form:

W = c L b {\displaystyle W=cL^{b}\!\,} W=cL^{b}\!\,

Invariably, b is close to 3.0 for all species, and the constant ct varies between species.[9] Data from the Florida Fish and Wildlife Conservation Commission indicate, for the gafftopsail catfish, c = 0.000493 and b = 3.075[10] The relationship described in this section suggests a 12-inch gafftopsail catfish will weigh about one pound, while a 20-inch fish will likely weigh about five pounds.

References

  1. ^ a b c Chao, L.; Vega-Cendejas, M.; Tolan, J.; Jelks, H. & Espinosa-Perez, H. (2015). "Bagre marinus". IUCN Red List of Threatened Species. Version 2017.1. International Union for Conservation of Nature. Retrieved 18 February 2017. 
  2. ^ "Synonyms of Bagre marinus (Mitchill, 1815)". Fishbase.org. Retrieved 29 July 2017. 
  3. ^ Smith, C. Lavett. National Audubon Society Field Guide to Tropical Marine Fishes of the Caribbean, the Gulf of Mexico, Florida, the Bahamas, and Bermuda. Chanticleer Press, 1997, ISBN 0-679-44601-X, pp. 85 & 346
  4. ^ FishBase.org: Food and Feeding Habits Summary - Bagre Marinus see online accessed 11 March 2010
  5. ^ Muncy R.J., Wingo W.M.,Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Gulf of Mexico): Sea Catfish and Gafftopsail Catfish read online p. 4
  6. ^ Smith, pp. 85 & 346
  7. ^ IGFA 2007 Database of IGFA angling records. IGFA, Ft. Lauderdale, FL, USA http://www.igfa.org/Records/Fish-Records.aspx?Fish=Catfish, gafftopsail&LC=ATR
  8. ^ Froese, Rainer and Pauly, Daniel, eds. (2017). "Bagre marinus" in FishBase. February 2017 version.
  9. ^ R. O. Anderson and R. M. Neumann, Length, Weight, and Associated Structural Indices, in Fisheries Techniques, second edition, B.E. Murphy and D.W. Willis, eds., American Fisheries Society, 1996.
  10. ^ average of data for male and female gafftopsail catfish at Florida Fish and Wildlife Conservation Commission Report 2008 accessed 7 March 2010
source: http://en.wikipedia.org/wiki/Gafftopsail_catfish

Jack Crevalle – 1


Jack Crevalle | Caranx hippos


 

Jack Crevalle info via Wikipedia:

Crevalle jack
Jack crevalle - Oleta River State Park.jpg
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Carangidae
Genus: Caranx
Species: C. hippos
Binomial name
Caranx hippos
(Linnaeus, 1766)
Caranx hippos distribution.png
Approximate range of the crevalle jack
Synonyms
  • Scomber hippos Linnaeus, 1766
  • Carangus hippos (Linnaeus, 1766)
  • Scomber carangus Bloch, 1793
  • Caranx carangus (Bloch, 1793)
  • Caranx carangua Lacepède, 1801
  • Caranx erythrurus Lacepède, 1801
  • Caranx antilliarum Bennett, 1840
  • Caranx defensor DeKay, 1842
  • Trachurus cordyla Gronow, 1854
  • Carangus esculentus Girard, 1859
  • Caranx esculentus (Girard, 1859)
  • Caranx hippos hippos (Linnaeus, 1766)
  • Caranx hippos tropicus Nichols, 1920

The crevalle jack, Caranx hippos (also known as the common jack, black-tailed trevally, couvalli jack, black cavalli, jack crevale and yellow cavalli) is a common species of large marine fish classified within the jack family, Carangidae. The crevalle jack is distributed across the tropical and temperate waters of the Atlantic Ocean, ranging from Nova Scotia, Canada to Uruguay in the west Atlantic and Portugal to Angola in the east Atlantic, including the Mediterranean Sea. It is distinguishable from similar species by its deep body, fin colouration and a host of more detailed anatomical features, including fin ray and lateral line scale counts. It is one of the largest fish in the genus Caranx, growing to a maximum known length of 124 cm and a weight of 32 kg, although is rare at lengths greater than 60 cm. The crevalle jack inhabits both inshore and offshore waters to depths of around 350 m, predominantly over reefs, bays, lagoons and occasionally estuaries. Young fish dispersed north by currents in the eastern Atlantic are known to migrate back to more tropical waters before the onset of winter; however, if the fish fail to migrate, mass mortalities occur as the temperature falls below the species' tolerance limits.

The crevalle jack is a powerful, predatory fish, with extensive studies showing the species consumes a variety of small fish, with invertebrates such as prawns, shrimps, crabs, molluscs and cephalopods also of minor importance. Dietary shifts with both age, location and season have been demonstrated, which led some researchers to postulate the species is indiscriminant in its feeding habits. The crevalle jack reaches maturity at 55 cm in males and 66 cm in females, with spawning taking place year round, although peaks in activity have been documented in several sites. The larval and juvenile growth has been extensively studied, with the oldest known individual 17 years of age. The crevalle jack is an important species to commercial fisheries throughout its range, with annual catches ranging between 1000 and 30 000 tonnes over its entire range. It is taken by a variety of netting methods, including purse nets, seines and gill nets, as well as hook-and-line methods. The crevalle jack is also a revered gamefish, taken both by lures and bait. The species is considered of good to poor quality table fare, and is sold fresh, frozen, or preserved, or as fishmeal or oil at market. The crevalle jack is closely related to both the Pacific crevalle jack and the longfin crevalle jack, the latter of which has been extensively confused with the true crevalle jack until recently.

Taxonomy and phylogeny

The crevalle jack is classified within the genus Caranx, one of a number of groups known as the jacks or trevallies. Caranx itself is part of the larger jack and horse mackerel family Carangidae, a group of percoid fishes in the order Perciformes.[1] The species belongs to what William Smith-Vaniz and Ken Carpenter refer to as the Caranx hippos complex, a group of closely related fishes which also includes Caranx caninus (Pacific crevalle jack) and Caranx fischeri (longfin crevalle jack).[2]

The crevalle jack was the first species of its genus to be scientifically described and named, and is also the type species of the genus Caranx. It was described and named in 1766 by the famed Swedish taxonomist Carl Linnaeus, based on the holotype specimen taken off the coast of the Carolinas, United States.[3] He named the species Scomber hippos, placing it in the mackerel genus Scomber, a practice which was common prior to 1801 when the carangids were not yet recognised as separate from the scombrids.[4] The specific epithet means "horse" in Latin, with Scomber hippos literally translating in English as "horse mackerel", which has become a common name for many species of carangid.[5] As the state of fish taxonomy progressed, the species was transferred to both Caranx and Carangus, with the name Caranx hippos now accepted. Bernard Germain de Lacépède was the first person to separate the crevalle jack from the mackerels, placing it in its own genus Caranx, although he had redescribed the fish as Caranx carangua, which became the type species of Caranx.[6] As well as Lacepede's renaming, the species has been independently redescribed a total of six times, with all of these names, including Lacepede's, categorised as invalid junior synonyms under ICZN rules.

There has been extensive discussion in the scientific literature regarding the possible conspecifity of the Pacific crevalle jack, Caranx caninus, with Caranx hippos.[2] Arguments ranged from the species being conspecific, subspecific or as individual species. This led to the creation of two trinomial names; Caranx hippos hippos and Caranx hippos tropicus. The former was an attempt to separate the 'subspecies' on each side of the Americas,[7] while the latter was an unnecessary name to divide the Atlantic Caranx hippos into subspecies.[8] The most recent review of the species complex by Smith-Vaniz and Carpenter treated the fish as separate species, citing differences in the development of hyperostosis and differing anal fin colours as evidence of species status.[2] The species' most often used common name, crevalle jack (or 'jack crevalle') is based on the word "cavalla", an earlier word used for the jacks. Other names include common jack, black-tailed trevally, couvalli jack, black cavalli, yellow cavalli and a host of generic names, such as horse mackerel and crevalle.[5]

Description

Several crevalle jacks over a reef in Florida

The crevalle jack is one of the largest members of Caranx, growing to a known maximum length of 125 cm and a weight of 32 kg,[5] although it is generally uncommon at lengths greater than 65 cm.[9] Unverified reports of fish over 150 cm may also be attributable to this species.[10] The crevalle jack is morphologically similar to a number of other deep-bodied carangids, having an elongate, moderately compressed body with the dorsal profile more convex than the ventral profile, particularly anteriorly.[10] The eye is covered by a well-developed adipose eyelid, and the posterior extremity of the jaw is vertically under or past the posterior margin of the eye.[10] The dorsal fin is in two parts, the first consisting of eight spines and the second of one spine followed by 19 to 21 soft rays. The anal fin consists of two anteriorly detached spines followed by one spine and 16 or 17 soft rays.[9] The pelvic fins contain one spine and five soft rays, while the pectoral fins contain 20 or 21 soft rays. The caudal fin is strongly forked, and the pectoral fins are falcate, being longer than the length of the head.[11] The lateral line has a pronounced and moderately long anterior arch, with the curved section intersecting the straight section midway below the second dorsal fin. The straight section contains 23 to 35 very strong scutes, with bilateral keels present on the caudal peduncle. The chest is devoid of scales with the exception of a small patch of scales in front of the pelvic fins.[9] The upper jaw contains a series of strong outer canines with an inner band of smaller teeth, while the lower jaw contains a single row of teeth.[10] The species has 35 to 42 gill rakers in total and 25 vertebrae are present.[11]

In 1972, a crevalle jack caught by fishermen off South Carolina displayed swollen, bulbous mandibles. These swellings were initially thought to be due to a copepod parasite, however radiographs and subsequent sectioning found them to be bony in nature. The cause of this calcified connective tissue is still unknown, and there remains only a single reported case of such an ailment in crevalle jack.[12]

The crevalle jack's colour ranges from brassy green to blue or bluish-black dorsally, becoming silvery white or golden ventrally. A dark spot is present on the pectoral fin, with a similar dark to dusky spot present on the upper margin of the operculum. Juveniles have around five dark vertical bands on their sides, with these fading at adulthood.[13] The first dorsal fin, pectoral and pelvic fins range from white to dusky, occasionally with golden tinges throughout. The anal fin lobe is bright yellow, with the remainder of the fin ranging from golden to dusky, while the underside of the caudal peduncle often being yellow in adults. The caudal fin itself is also golden to dusky, with the lower lobe often brighter yellow than the upper, with both the lobes often having a black trailing edge.[11][13]

Distribution

The crevalle jack inhabits the tropical and temperate waters of the Atlantic Ocean, ranging extensively along both the eastern American coastline and the western African and European coastlines.[5] In the western Atlantic, the southernmost record comes from Uruguay, with the species ranging north along the Central American coastline, and throughout the Caribbean and many of the numerous archipelagos within. The species is found throughout the Greater Antilles, however it is absent from the leeward Lesser Antilles, with its distribution being patchy throughout other Caribbean archipelagos.[10] From the Gulf of Mexico, its distribution extends north along the U.S. coast and as far north as Nova Scotia in Canada, also taking in several northwest Atlantic islands. The crevalle jack is also known from Saint Helena Island in the southern Atlantic Ocean.[14]

In the eastern Atlantic, the southernmost record comes from Angola, with the species distributed north along the west African coastline up to West Sahara and Morocco, with its distribution also including much of the Mediterranean Sea.[5] In the Mediterranean, its range extends as far east as Libya in the south and Turkey in the north, and includes most of the northern Mediterranean, including Greece, Italy and Spain. The species' northernmost record in the eastern Atlantic comes from Portugal, with the species also known to inhabit many of the northeastern Atlantic islands, including Cape Verde, Madeira Island, and the Canary Islands.[9]

Many older publications list the species range as from the eastern Pacific, which now is known to represent the Pacific crevalle jack and is considered a distinct species. There are also often mentions of the species erroneously having circumtropical and Indian Ocean distributions, with these records probably attributable to similar Indo-Pacific species, namely the blacktip trevally and giant trevally.[2] The species distribution overlaps that of the similar longfin crevalle jack in the eastern Atlantic, with careful identification needed to distinguish the two.[2] Within the Atlantic, confusion with both longfin crevalle jack and horse-eye jack, Caranx latus, have also led to erroneous records being made, with Smith-Vaniz and Carpenter suggesting this occurred in the Mediterranean, and the species may actually be absent from waters north of Mauritania.[2]

Habitat

Crevalle jacks swimming in the Georgia Aquarium

The crevalle jack lives in both inshore and offshore habitats, with larger adults preferring deeper waters than juveniles. In the inshore environment, crevalle jack inhabit shallow flats, sandy bays,[15]beaches, seagrass beds, shallow reef complexes[5] and lagoons. The species is also known to enter brackish waters, with some individuals known to penetrate far upstream; however, like most euryhaline species, they generally do not penetrate very far upriver.[16] The water salinities where the species has been reported from range from 0% to 49%, indicating the species can adapt to a wide range of waters.[17] Studies in West Africa found marked differences in the sex ratios of populations in brackish waters, with females very rarely seen in such environments once they are mature.[17] Research in the coastal waters of Ghana suggests the availability of food is the primary control on the species distribution in inshore waters.[18]

Adults that move offshore generally do not leave continental shelf waters, however still penetrate to depths of 350 m,[9] and possibly deeper. These individuals live on the outer shelf edges, sill reefs and upper slopes of the deep reef, and tend to be more solitary than juveniles.[19] Adults have also been sighted around the large oil rig platforms throughout the Gulf of Mexico, where they use the man-made structure like a reef to hunt prey.[20] The larvae and young juveniles of the species live pelagically offshore along the continental shelf and slope, and are also known to congregate around oil platforms, as well as natural floating debris such as sargassum mats.[21]

Biology and ecology

The crevalle jack is one of the most abundant large carangids in the Atlantic Ocean, with at least two systematic studies placing it within the top five most abundant species of that region, namely lagoons in Nigeria and Chiapas, Mexico.[22] Seasonal movements are known from both the American and African coastlines, with both juveniles and adults appearing to migrate. In North America, young individuals recruited to northern estuaries are known to move to warmer tropical waters at the onset of winter to escape possible hypothermia.[23] At least one hypothermia-driven mass mortality of 200 crevalle jacks has been reported from the Slocum River in Massachusetts, indicating low-temperature mortality is a major concern for north-ranging groups of the species, with temperatures below 9.0 °C apparently being lethal to the fish.[24] This applies not only to river dwelling fish, but also to marine migrants which linger too long in the temperate regions during winter.[24] In Nigeria, and presumably other parts of Africa, the species appears to migrate seasonally, possibly to take advantage of prey, with the fish arriving in Nigeria during September to November. The species is more active during the day than the night, with larger catches in fisheries taken during the day, also. The crevalle jack is a schooling species for most of its life, forming moderately large to very large, fast-moving schools.[11] At larger sizes, the fish become more solitary and move to the deeper offshore reefs. Evidence from laboratory studies indicates crevalle jack are able to coordinate their feeding and spawning aggregations over coral reefs based on the release of dimethylsulfoniopropionate (DMSP) from the reef. DMSP is a naturally occurring chemical produced by marine algae and, to a lesser extent, corals and their symbiotic zooxanthellae. Field studies have also shown the species increases in abundance with increased levels of DMSP over coral reefs.[25]

Diet and feeding

The crevalle jack is a powerful predatory fish which predominantly takes other small fishes as prey at all stages of its life, with various invertebrates generally being of secondary importance to its diet.[10] Several studies conducted on the species' diet over its range have found other aspects of its diet vary widely, including the specific types of prey the species takes and the change in diet with age. The most detailed of these studies was conducted in the Southern USA, which showed the species diet comprised between 74% and 94% fish.[26] The remainder of the diet was various prawns, shrimps, crabs, molluscs and stomatopods. The types of fish taken varied throughout the range, with members of Clupeidae, Sparidae, Carangidae and Trichiuridae all taken in variable amounts, usually with members of one family dominating the local diet.[26] The percentage of various invertebrates also was highly variable, with penaeid shrimps, portunid crabs, stomatopods and squid being of importance to different populations. The study also indicated young crevalle jack predominantly take clupeids, adding sparids and later carangids to their diets as they grow larger.[26] The larger individuals also took much higher amounts of invertebrates, and also small quantities of seagrass, indicating larger fish are more opportunistic.[26] This general change in diet with age also seems spatially variable, with young crevalle jack in both Maryland and Puerto Rico consuming almost exclusively crustaceans, including shrimps, crabs (and juvenile tarpon) in Maryland[27] and harpacticoid copepods in Puerto Rico before moving to fish-dominated diets later in life.[19] Research in Ghana shows a pattern somewhat intermediate to the previous two locations; adults take larger fish, predominantly Engraulis guineensis and Sardinella eba, while juvenile fish take smaller fishes such as Epiplatys sexfasciatus or juvenile caridian and penaeid shrimps.[18]

The widely variable diet of the species throughout its life stages led authors in the 1950s and 1960s to conclude the species was indiscriminate in its feeding habits, eating whatever was locally available.[28][29] The diets of the populations in both the southern USA and Ghana also varied quite markedly by season and year, which led the authors of both these studies to agree with these earlier conclusions.[26] Recent laboratory studies, however, have shown the species may have preferences for certain sizes of prey. In these experiments, the fish were presented with a range of size classes of the same prey species, Menidia beryllina, with the results showing they prefer to take the smallest size class possible, which contrasts with more aggressive predators, such as bluefish.[30] Both adults and juveniles feed throughout the day, generally becoming inactive at night.[18] During some feeding periods recorded in Ghana, digestion in the species was so rapid that food becomes unidentifiable within four to five hours of consumption.[18] The crevalle jack is also an important prey species itself, taken by larger fish, such as billfish and sharks, as well as seabirds.[5] As well as being preyed on during its adult stage, the spawn of the crevalle jack is known to be eaten by planktivorous organisms, including whale sharks in the Caribbean.[31]

Life history

A school of crevalle jack swarming around a Caribbean reef shark

The crevalle jack reaches sexual maturity at different lengths in males and females, with estimates suggesting males reach maturity at 55 cm and four to five years of age, and females at 66 cm and five to six years of age.[19] Reproduction is thought to occur year round in most areas, although there are peaks in activity. South of Florida, this period is between March and September,[32] in Cuba it is April and May,[5] while in Jamaica no definitive peak has yet been identified.[19] The species also has a protracted spawning in Ghana, although a peak in activity occurs between October and January. Juveniles are also present in lagoons year round in this location, indicating year round spawning and recruitment.[18] The place of spawning also appears to be variable, with the act occurring offshore south of Florida,[32] while in Colombia and Belize, they have been observed spawning over inshore reefs and bays.[33] Large aggregations of crevalle jack form prior to spawning, with these schools containing upward of 1000 individuals. Pairs break off from the school to spawn, with one individual turning a much darker color during this exchange. Once spawning has occurred, the pair rejoins the main school.[33]Fecundity in the species has been estimated as up to one million eggs, with these being pelagic, and spherical in shape. They have a diameter of 0.7 to 0.9 mm, and contain a pigmented yolk and one yellow oil globule with dark pigments.[19] The larvae have been extensively described in the scientific literature, although the sequence of fin formation is still not well known. Defining features of the larval crevalle jack include a relatively deep body, heavily pigmented head and body, and more detailed meristic characteristics, with flexion occurring at 4 to 5 mm in length.[32]

Otolith and vertebrae studies have proved useful in determining the age and thus growth patterns of the species, with other methods including scale and fin ray sectioning having lesser value.[34] The species otoliths have been the subject of detailed X-ray diffraction studies, which have indicated biomineralisation of the otoliths occurs predominantly in the aragonite phase.[35] Females grow faster than males, reaching 266.5 mm after their first year of life, 364.4 after their second, 370.9 mm after the third and 546.7 after their fifth. A female of 676.6 mm was 9 years old.[36] Males reach 252.4 mm in their first year, 336.2 mm in their second, 363.8 in the third and 510.3 in their fifth. A male of 554 mm was eight years old.[36] The oldest studied individual was a 934-mm individual of unspecified sex, which was 17 years old.[34] The larvae are pelagic and are found over continental shelf waters and occasionally in the oceanic zone proximal to the continental slope. They are present all year round in the Gulf of Mexico, with a peak in abundance during the summer months due to spawning peaks.[37] While the young juveniles live in the exposed pelagic environment, they use a behaviour called 'piloting' to swim in very close proximity to both larger animals and floating objects, such as sargassum mats, buoys and even boats.[38] By the time juveniles make their way to shore, they may have been dispersed large distances from their initial spawning grounds and may face the challenge of migration to warmer climates during winter if they are to survive as outlined previously.[23] Juveniles use estuaries and seagrass beds as their main nursery habitats.[38]

Relationship to humans

The crevalle jack is a highly important species to commercial fisheries throughout its range, with the greatest quantity of the species taken from the eastern Atlantic.[39] In some fisheries, it is one of the most abundant species and therefore of great importance in these regions. In the Americas, the reported annual catch has ranged between 150 and 1300 tonnes since 1950, with catches since 2000 ranging between 190 and 380 tonnes.[39] Most of the western Atlantic catch is from Florida,[2] although Caribbean fisheries, such as Trinidad, take considerable quantities of the fish.[36] The eastern Atlantic catch statistics do not differentiate longfin crevalle jack from crevalle jack, thus must be considered a composite dataset. This region only comprises catch data from Angola, Ghana, São Tome, and Principe. These catches are much larger than in the east, with hauls of between 1000 and 38 000 tonnes per year recorded since 1950, although catches since 2000 only range between 1900 and 10 200 tonnes.[39] Crevalle jack is taken by a number of fishing methods, including haul seines, gill nets, purse seines, trawls, handlines and trolling lines.[10] The abundance of the species in Trinidad leads to the fish being taken in several quite different types of fishery; demersal trawls, artisanal gill nets and even beach seines, which illustrates the species' importance. In Trinidad, recreational fishermen also may sell their catch, which adds to the overall quantity of fish sold.[40] Crevalle jack is sold at market fresh, frozen, salted, and smoked, and as fishmeal and oil.[9]

The crevalle jack is a popular and highly regarded gamefish throughout its range, with the recreational catch of the species often exceeding commercial catches. The only amateur catch data available are from the US, which has an annual catch of around 400 to 1000 tonnes per year.[2] In Trinidad, the species is the basis for several fishing tournaments.[36] Crevalle jack are targeted from boats, as well as from piers and rockwalls by land based anglers.[41] Fishermen often target regions where depth suddenly changes, such as channels, holes, reefs or ledges, with strong currents and eddies favourable.[42] The fish take both live and cut baits, as well as a variety of artificial lures; however, when the fish are in feeding mode, they rarely refuse anything they are offered. Popular baits include both live fish, such as mullet and menhaden, as well as dead or strip baits consisting of fish, squid or prawns. Crevalle jack readily accept any style of lure, including hard-bodied spoons, jigs, plugs and poppers, as well as flies and soft rubber lures.[42] There is some evidence based on long term observations that the species favours yellow lures over all others.[42] Tackle is often kept quite light, but heavy monofilament leaders are employed to prevent the fish's teeth from abrading the line.[42] Crevalle jack are generally considered quite poor table fare, with selection of younger fish and bleeding upon capture giving the best results. The flesh is very red and dark due to the red muscle of the fish, which makes it somewhat coarse and poor tasting.[9] When pulled from the water, this fish snorts in what many people describe as "a pig-like" fashion. The crevalle jack has been implicated in several cases of ciguatera poisoning, although appears less likely to be a carrier than the horse-eye jack.[43]

References

  1. ^ "Caranx hippos". Integrated Taxonomic Information System. Retrieved 29 May 2009. 
  2. ^ a b c d e f g h Smith-Vaniz, W.F.; K.E. Carpenter (2007). "Review of the crevalle jacks, Caranx hippos complex (Teleostei: Carangidae), with a description of a new species from West Africa" (PDF). Fisheries Bulletin. 105 (4): 207–233. Retrieved 2009-04-07. 
  3. ^ California Academy of Sciences: Ichthyology (May 2009). "Caranx hippos". Catalog of Fishes. CAS. Retrieved 2009-05-31. 
  4. ^ Cuvier, G.; A. Valenciennes (1849). Histoire naturelle des poissons. F.G. Levrault. pp. IX, 93. 
  5. ^ a b c d e f g h Froese, Rainer and Pauly, Daniel, eds. (2009). "Caranx hippos" in FishBase. May 2009 version.
  6. ^ Lacepède, B.G.E. (1801). Histoire naturelle des poissons. 3: i-xvi. Paris: Plassan. pp. 1–558. 
  7. ^ Nichols, J.T. (1937). "On Caranx hippos (Linnaeus) from Ecuador". Copeia. American Society of Ichthyologists and Herpetologists. 1937 (1): 58–59. doi:10.2307/1437371. ISSN 0045-8511. JSTOR 1437371. 
  8. ^ Nichols, J.T. (1920). "On the range and geographic variation of Caranx hippos". Copeia. 83: 44–45. doi:10.2307/1437199. ISSN 0045-8511. 
  9. ^ a b c d e f g Fischer, W; Bianchi, G.; Scott, W.B. (1981). FAO Species Identification Sheets for Fishery Purposes: Eastern Central Atlantic Vol 1. Ottawa: Food and Agricultural Organization of the United Nations. 
  10. ^ a b c d e f g Carpenter, K.E. (ed.) (2002). The living marine resources of the Western Central Atlantic. Volume 3: Bony fishes part 2 (Opistognathidae to Molidae), sea turtles and marine mammals (PDF). FAO Species Identification Guide for Fishery Purposes and American Society of Ichthyologists and Herpetologists Special Publication No. 5. Rome: FAO. p. 1438. ISBN 92-5-104827-4. CS1 maint: Extra text: authors list (link)
  11. ^ a b c d McEachran, J.D.; J.D. Fechhelm (2005). Fishes of the Gulf of Mexico: Scorpaeniformes to tetraodontiformes. Austin, TX: University of Texas Press. p. 1014. ISBN 978-0-292-70634-7. 
  12. ^ Schwartz, F.J. (1975). "A Crevalle Jack, Caranx hippos (Pisces, Carangidae), with a Mandibular Calcified Connective Tissue Fibroma". Chesapeake Science. Coastal and Estuarine Research Federation. 16 (1): 72–73. doi:10.2307/1351089. JSTOR 1351089. 
  13. ^ a b Wiseman, C. (1996). Guide to Marine Life: Caribbean, Bahamas, Florida. Miami: Aqua Quest Publications, Inc. p. 284. ISBN 978-1-881652-06-9. 
  14. ^ Edwards, A.J.; C.W. Glass (1987). "The Fishes of Saint Helena Island, Southern Atlantic Ocean. 2: The Pelagic Fishes". Journal of Natural History. 21 (6): 1367–1394. doi:10.1080/00222938700770871. ISSN 0022-2933. 
  15. ^ Ospina-Arango, J.F.; F.I. Pardo-Rodríguez; R. Álvarez-León (2008). "Gonadal maturity of the fish in the Cartagena Bay, Colombian Caribbean" (PDF). Boletin Cientifico Museo de Historia Natural Universidad de Caldas. 12 (9): 117–140. ISSN 0123-3068. Archived from the original (PDF) on 2011-07-07. Retrieved 2009-05-31. 
  16. ^ Loftus, W.S.; J.A. Kushlan (1987). "Freshwater Fishes of Southern Florida USA". Bulletin of the Florida State Museum Biological Sciences. 31 (4): 147–344. ISSN 0071-6154. 
  17. ^ a b Panfili, J.; D. Thior; J.-M. Ecoutin; P. Ndiaye; J.-J. Albaret (2006). "Influence of salinity on the size at maturity for fish species reproducing in contrasting West African estuaries". Journal of Fish Biology. 69 (1): 95–113. doi:10.1111/j.1095-8649.2006.01069.x. 
  18. ^ a b c d e Kwei, E.A. (1978). "Food and spawning activity of Caranx hippos (L.) off the coast of Ghana". Journal of Natural History. 12 (2): 195–215. doi:10.1080/00222937800770081. ISSN 0022-2933. 
  19. ^ a b c d e Munro, J. L. (1983) [1974]. "The Biology, Ecology and Bionomics of the Jacks, Carangidae". Caribbean Coral Reef Fishery Resources (A second edition of The biology, ecology, exploitation, and management of Caribbean reef fishes : scientific report of the ODA/UWI Fisheries Ecology Research Project, 1969-1973, University of the West Indies, Jamaica.). Manila: International Center for Living Aquatic Resources Management. pp. 82–94. ISBN 971-10-2201-X. 
  20. ^ McGinnis, M.V.; L. Fernandez; C. Pomery (2001). "The Politics, Economics, and Ecology of Decommissioning Offshore Oil and Gas Structures" (PDF). MMS OCS Study 2001-006. Coastal Research Center, Marine Science Institute, University of California: 107. Retrieved 2009-06-11. 
  21. ^ Lindquist, D.C.; R.F. Shaw; F.J. Hernandez (2005). "Distribution patterns of larval and juvenile fishes at offshore petroleum platforms in the north-central Gulf of Mexico". Estuarine, Coastal and Shelf Science. 62 (4): 655–665. doi:10.1016/j.ecss.2004.10.001. 
  22. ^ Diaz-Ruiz, S.; A. Aguirre-Leon; E. Cano-Quiroga (2006). "Ecological evaluation of fish community in two lagoon-estuarine systems of the south of Chiapas, Mexico". Hidrobiologica (in Spanish). 16 (2): 197–210. ISSN 0188-8897. 
  23. ^ a b McBride, R.S.; K.A. McKown (2000). "Consequences of dispersal of subtropically spawned crevalle jacks, Caranx hippos, to temperate estuaries" (PDF). Fishery Bulletin. 98 (3): 528–538. Retrieved 2009-06-11. 
  24. ^ a b Hoff, J.G. (1971). "Mass Mortality of the Crevalle Jack, Caranx hippos (Linnaeus) on the Atlantic Coast of Massachusetts". Chesapeake Science. Coastal and Estuarine Research Federation. 12 (1): 49. doi:10.2307/1350504. JSTOR 1350504. 
  25. ^ Debose, J.L.; G.A. Nevitt; A.H. Dittman (2006). "Evidence for DMSP as a Chemosensory Stimulant for Pelagic Jacks (Abs.)". Integrative and Comparative Biology. 46 (Suppl. 1): E187–E187. doi:10.1093/icb/icl057. ISSN 1540-7063. 
  26. ^ a b c d e Saloman, C.H.; S.P. Naughton (1984). "Food of crevalle jack (Caranx hippos) from Florida, Louisiana, and Texas". NOAA Technical Memorandum NMFS-SEFC-134: 1–37. ISSN 0093-4917. 
  27. ^ Taylor, M.; R.J. Mansueti (1960). "Sounds Produced by Very Young Crevalle Jack, Caranx hippos, from the Maryland Seaside". Chesapeake Science. Coastal and Estuarine Research Federation. 1 (2): 115–116. doi:10.2307/1350930. JSTOR 1350930. 
  28. ^ Cadenat, J.A. (1954). "Note d' Ichthyologie Ouest-africaine VII Biologie, Regime alimentaire Carangidae". Bulletin de l'Institut Fondamental d'Afrique Noire (Series A). 16 (21): 565–583. ISSN 0850-4997. 
  29. ^ Zai, M. (1965). "Biological investigation of fisheries resources". FAO, EPTA Report No. 2001. Ghana Government. 
  30. ^ Gleason, T.R.; D.A. Bengston (1996). "Growth, survival and size-selective predation mortality of larval and juvenile inland silversides, Menidia beryllina (Pisces; Atherinidae)". Journal of Experimental Marine Biology and Ecology. 199 (2): 165–177. doi:10.1016/0022-0981(95)00194-8. ISSN 0022-0981. 
  31. ^ Hoffmayer, E.R.; J.S. Franks; W.B. Driggers; K.J. Oswald; J.M. Quattro (2007). "Observations of a feeding aggregation of whale sharks, Rhincodon typus, in the North Central Gulf of Mexico". Gulf and Caribbean Research. 19 (2): 69–73. ISSN 1528-0470. 
  32. ^ a b c Richards, William J. (2006). Early Stages of Atlantic Fishes: An Identification Guide for the Western Central North Atlantic. CRC Press. pp. 2640 pp. ISBN 978-0-8493-1916-7. 
  33. ^ a b Graham, Rachel T.; Daniel W. Castellanos (2005). "Courtship and spawning behaviors of carangid species in Belize" (PDF). Fishery Bulletin. 103 (2): 426–432. Retrieved 2008-08-04. 
  34. ^ a b Palko, B.J. (1984). "An evaluation of hard parts for age determination of pompano (Trachinotus carolinus), ladyfish (Elops saurus), crevalle jack (Caranx hippos), gulf flounder (Paralichthys albigutta), and southern flounder (Paralichthys lethostigma)". NOAA Technical Memorandum NMFS-SEFC-132: 1–16. 
  35. ^ Pattanaik, S. (2005). "X-ray diffraction, XAFS and scanning electron microscopy study of otolith of a crevalle jack fish (Caranx hippos)". Nuclear Instruments and Methods in Physics Research Section B. 229 (3-4): 367–374. doi:10.1016/j.nimb.2004.12.133. ISSN 0168-583X. 
  36. ^ a b c d Kishore, R.; F. Solomon (2005). "Age and Growth Studies of Caranx hippos (crevalle jack) from Trinidad Using Hard-Parts". 56 Proceedings of the Fifty Six Annual Gulf and Caribbean Fisheries Institute. 56: 227–239. 
  37. ^ Flores-Coto, C.; M. Sanchez-Ramirez (1989). "Larval Distribution and Abundance of Carangidae (Pisces) from the Southern Gulf of Mexico 1983-1984". Gulf Research Reports. 8 (2): 117–128. ISSN 0072-9027. 
  38. ^ a b Wiggers, S. (2005). "Crevalle Jack, Caranx hippos" (PDF). Species Description. South Carolina Department of Natural Resources. pp. 1–4. Retrieved 2009-06-16. 
  39. ^ a b c Fisheries and Agricultural Organisation. "Global Production Statistics 1950-2007". Crevalle jack. FAO. Retrieved 2009-05-19. 
  40. ^ Mike, A.; Cowx, I.G. (1996). "A preliminary appraisal of the contribution of recreational fishing to the fisheries sector in north-west Trinidad". Fisheries Management and Ecology. 3 (3): 219–228. doi:10.1111/j.1365-2400.1996.tb00149.x. 
  41. ^ Goldstein, R.J. (2000). Coastal fishing in the Carolinas: from surf, pier, and jetty. John F. Blair. p. 117. ISBN 978-0-89587-195-4. 
  42. ^ a b c d McNally, B. (2001). Gibson, B, ed. Inshore Salt Water Fishing: Learn from the Experts at Salt Water Magazine. Rockport Publishers. pp. 82–83. ISBN 978-0-86573-132-5. 
  43. ^ Doorenbos, N.J.; Granade, H.R.; Cheng, P.C.; Morgan, J.M. (1977). "Ciguatera Fish Poison Studies in the Caribbean" (PDF). Mississippi-Alabama Sea Grant Consortium Technical Report. MASGP-77-023: 1–7. Archived from the original (PDF) on 2008-11-16. Retrieved 2009-09-14. 
source: http://en.wikipedia.org/wiki/Jack_crevalle

 

Atlantic Stingray


Atlantic Stingray | Dasyatis sabina 

 


 

Atlantic Stingray info:

Atlantic stingray
Dasyatis sabina florida.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Myliobatiformes
Family: Dasyatidae
Genus: Dasyatis
Species: D. sabina
Binomial name
Dasyatis sabina
(Lesueur, 1824)
Dasyatis sabina rangemap.png
Range of the Atlantic stingray
Synonyms

Trygon sabina Lesueur, 1824

The Atlantic stingray (Dasyatis sabina) is a species of stingray in the family Dasyatidae, common along the Atlantic coast of North America from Chesapeake Bay to Mexico, including brackish and freshwater habitats. It may be distinguished from other stingrays in the area by its relatively elongated snout.[2] This species is of little commercial importance,[3] other than for sale in the aquarium industry.

Taxonomy and phylogeny

The Atlantic stingray was described by French naturalist Charles Alexandre Lesueur as Trygon sabina, in an 1824 volume of the Journal of the Academy of Natural Sciences of Philadelphia. He based his account on a damaged male specimen collected by American naturalist Titian Ramsay Peale during the Academy's 1817 expedition to Florida.[4] Since then, various authors have included this species in the obsolete genera Pastinaca, Dasybatus (or the variants Dasibatis and Dasybatis), and Amphotistius, all of which were eventually synonymized with the genus Dasyatis.[5]

A 2001 phylogenetic analysis by Lisa Rosenberger, based on morphology, found that the Atlantic stingray is one of the more basal members of its genus. It is the outgroup to a large clade that contains, amongst others, the southern stingray (D. americana), the roughtail stingray (D. centroura), the longnose stingray (D. guttata), and the pearl stingray (D. margaritella).[6]

Distribution and habitat

The Atlantic stingray is found over fine substrates.

The Atlantic Stingray is found in the western Atlantic Ocean from Chesapeake Bay southward to Florida and the Gulf of Mexico, to as far as Campeche, Mexico.[1] Records of this species from Grenada, Suriname, and Brazil are doubtful and may represent other species. The Atlantic stingray is capable of tolerating varying salinities and can enter freshwater; it has been reported from the Mississippi River, Lake Pontchartrain, and the St. Johns River in Florida.[7] The stingrays in the St. Johns River system represent the only permanent freshwater elasmobranch population in North America.[2][8][9]

This species inhabits shallow coastal waters over sandy or silty bottoms, estuaries, and lakes. They prefer water temperatures over 15 °C (59 °F) and can tolerate temperatures over 30 °C (86 °F). These stingrays conduct seasonal migrations to stay in warmer water: they are only present in the northerly Chesapeake bay in the summer and fall, and elsewhere they migrate to deeper water in the winter. When inshore, they usually stay at depths of 2–6 m (6.6–19.7 ft), and after migrating offshore they may be found as deep as 25 m (82 ft).[2]

Description

One of the smallest stingray species, the Atlantic stingray attains a maximum length of 61 cm (24 in) and a weight of 4.9 kg (11 lb).[3] It has a spade-shaped pectoral fin disk 1.1 times as wide as long, with rounded corners and concave anterior margins. The snout is relatively long. There are three stout papillae on the floor of the mouth; the teeth are rounded, with a flat, blunt surface. During the reproductive season, the teeth of mature males change to feature long, sharp cusps that curve towards the corners of the mouth, for gripping onto females during mating. The tail is long and whip-like, with a serrated spine measuring a quarter of the width of the disk. The spine is replaced annually between June and October. Dorsal and ventral fin folds are present on the tail.[2][7]

Larger Atlantic stingrays develop tubercles or thorns along the midline of the back to the origin of the tail spine. Some larger females also develop tubercles around the eyes and spiracles. The coloration is brown or yellowish brown above, becoming lighter towards the margin of the disk and sometimes with a dark stripe along the midline, and white or light gray below. The tail fin folds are yellowish. In larger individuals the tail may be flecked with gray near the base and completely dark towards the tip.[2][7]

Biology and ecology

A fetal Atlantic stingray

The Atlantic stingray feeds mostly on benthic invertebrates such as bivalves, tube anemones, amphipods, crustaceans, and nereid worms, which they locate using their electroreceptive ampullae of Lorenzini. The exact composition of their diet varies by geographical location. When feeding, these rays will position themselves facing the current so that the sediment will be washed away.[10] Numerous species of sharks, such as the tiger shark (Galeocerdo cuvier) and the bull shark (Carcharhinas leucas), are major predators of the Atlantic stingray. In freshwater habitats, they may be preyed upon by American alligators (Alligator mississippiensis). A known parasite of freshwater Atlantic stingrays is Argulus, a fish louse that feeds on skin mucus.[2]

Despite having a regular freshwater presence, the Atlantic stingray is physiologically euryhaline and no population has evolved the specialized osmoregulatory mechanisms found in the river stingrays of the family Potamotrygonidae. This may be due to the relatively recent date of freshwater colonization (under one million years), and/or possibly incomplete genetic isolation of the freshwater populations, as they remain capable of surviving in salt water. Freshwater Atlantic stingrays have only 30–50% the concentration of urea and other osmolytes in their blood compared to marine populations. However, the osmotic pressure between their internal fluids and external environment still causes water to diffuse into their bodies, and they must produce large quantities of dilute urine (at 10 times the rate of marine individuals) to compensate.[8]

Like other stingrays, the Atlantic stingray is viviparous. Both marine and freshwater populations in Florida have an annual mating season from September or October to April, though ovulation does not occur until late March or early April. Courtship involves the male following the female and biting at her body and fins, and the male will grip onto the female's pectoral fin to assist in copulation. The embryos are sustained by a yolk sac until around day 60, after which they are nourished by uterine milk secreted by the mother (histotrophy). Litters of 1–4 young are born from late July to early August, after a gestation period of 4–4.5 months. Newborns measure 10–13 centimetres (3.9–5.1 in) wide. Marine males mature at a disk width of 20 cm (7.9 in) and females at a disk width of 24 cm (9.4 in). Freshwater males mature at a disk width of 21 cm (8.3 in) and females at a disk width of 22 cm (8.7 in).[2][11]

Human interactions

If stepped on, the Atlantic stingray can inflict a painful, though rarely life-threatening wound. Large numbers of Atlantic stingrays are caught as bycatch in gillnets targeting flounder off North Carolina, but most are released alive. They are also caught as bycatch in small numbers in recreational and commercial trout gillnets, shark drift nets, and nearshore trawls. As there is no fishery targeting this species and bycatch mortality appears to be low, it was assessed as of Least Concern by the World Conservation Union.[1] However, some localized freshwater populations have shown reduced health and reproduction due to declining water quality.[2]

References

  1. ^ a b c Piercy, A.; Snelson Jr., F.F. & Grubbs, R.D. (2006). "Dasyatis sabina". IUCN Red List of Threatened Species. Version 2008. International Union for Conservation of Nature. Retrieved March 8, 2009. 
  2. ^ a b c d e f g h Passarelli, N. and Piercy, A. Biological Profiles: Atlantic Stingray. Florida Museum of Natural History Ichthyology Department. Retrieved on March 9, 2009.
  3. ^ a b Froese, Rainer and Pauly, Daniel, eds. (2009). "Dasyatis sabina" in FishBase. March 2009 version.
  4. ^ Lesueur, C.A. (1824). "Description of several species of the Linnaean genus Raia, of North America". Journal of the Academy of Natural Sciences of Philadelphia. 4 (1): 100–121. 
  5. ^ Bigelow, H.B. and W.C. Schroeder (1953). Fishes of the Western North Atlantic, Part 2. Sears Foundation for Marine Research, Yale University. pp. 370–378.
  6. ^ Rosenberger, L.J.; Schaefer, S. A. (August 6, 2001). Schaefer, S. A., ed. "Phylogenetic Relationships within the Stingray Genus Dasyatis (Chondrichthyes: Dasyatidae)". Copeia. 2001 (3): 615–627. doi:10.1643/0045-8511(2001)001[0615:PRWTSG]2.0.CO;2. JSTOR 1448284. 
  7. ^ a b c McEachran, J.D. & Fechhelm, J.D. (1998). Fishes of the Gulf of Mexico: Myxiniformes to Gasterosteiformes. University of Texas Press. ISBN 0-292-75206-7. 
  8. ^ a b Piermarini, P.M. & Evans, D.H. (1998). "Osmoregulation of the Atlantic Stingray (Dasyatis sabina) from the Freshwater Lake Jesup of the St. Johns River, Florida". Physiological and Biochemical Zoology. 71 (5): 553–560. doi:10.1086/515973. PMID 9754532. 
  9. ^ Johnson, Michael R.; Snelson Jr., Franklin F. (1996). "Reproductive Life History of the Atlantic Stingray, Dasyatis Sabina (Pisces, Dasyatidae), in the Freshwater St. Johns River, Florida". Bulletin of Marine Science. 59 (1): 76. 
  10. ^ Murch, A. Atlantic stingray. Elasm-diver.com. Retrieved on March 8, 2009.
  11. ^ Snelson Jr., F.F.; Williams-Hooper, S.E. & Schmid, T.H. (Aug 3, 1988). "Reproduction and Ecology of the Atlantic Stingray, Dasyatis sabina, in Florida Coastal Lagoons". Copeia. American Society of Ichthyologists and Herpetologists. 1988 (3): 729–739. doi:10.2307/1445395. JSTOR 1445395. 
source: http://en.wikipedia.org/wiki/Atlantic_stingray

 

Southern Flounder

Souther Flounder by Inked Animal

Southern Founder | Paralichthys lethostigma

Southern Founder Skeleton | Paralichthys lethostigma

The Southern Flounder is one of my favorite fishes for many reasons.  It has a strange morphology (good for gyotaku printing), it is elusive and fun to land with rod & reel, and it tastes great!  This specimen came from one of our many outings to Matagorda Bay Texas, where we often fish and print fish (Gyotaku).

 

 


Southern Flounder info:

Southern flounder
Paralichthys lethostigma.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Pleuronectiformes
Family: Paralichthyidae
Genus: Paralichthys
Species: P. lethostigma
Binomial name
Paralichthys lethostigma
D. S. Jordan & C. H. Gilbert, 1884

The southern flounder (Paralichthys lethostigma) is a species of large-tooth flounders native to the eastern and gulf coasts of the United States. It is a popular sports fish and is the largest and most commercially valuable flounder in the western North Atlantic Ocean and Gulf of Mexico.[2] Its range is North Carolina to the Yucatan Peninsula.[3] It is a "left-eyed flounder", meaning the left side is pigmented and is the "up side".[4] The body color is brown with diffuse, unocellated spots and blotches.[2]

Description

Diet

Habitat

Reproduction and Life Cycle

Distribution

Importance to Humans

Southern flounders are a major and valuable species in the highly important commercial and recreational flounder fishery in the Gulf of Mexico. Most of the commercial catch in the Gulf of Mexico is incidental to the catch by shrimp trawlers. Recreationally, they can easily be caught by anglers on a line with either a lure or live bait.[2] Another popular form of collecting flounders is by night gigging. In this sport, anglers use a gig, or a multi-pronged spear, to impale the fish after using a flashlight to spot it in the waters at night.

Etymology

The genus name, Paralichthys, is usually interpreted as "parallel fish" in reference to the deeply compressed body shape. However, some interpret it as "close to the sea", from the Greek word, para, meaning beside or near. This can be in reference to the way it buries itself in the sand and lies flat as if it is a part of the sea floor itself.[5] The species name, lethostigma, comes from the Latin word, letho, meaning death, and the Greek word, stigma, meaning spots. The meaning "forgotten spots" or "death of spots" refers to the absences of conspicuous large occellaed spots that is common in other species of flatfish.[6]

See also

References

  1. ^ IUCN (2016). "Paralichthys lethostigma". IUCN Red List of Threatened Species. Version 2016.3. International Union for Conservation of Nature. Retrieved 26 November 2016. 
  2. ^ a b c Paralichthys lethostigma Smithsonian Marine Station at Fort Pierce. Species reports
  3. ^ Southern flounder South Carolina Department of Natural Resources species descriptions
  4. ^ Flounder Texas Parks and Wildlife Department species descriptions
  5. ^ Ross, Stephen T. (2001). Inland Fishes of Mississippi. Jackson, Mississippi: University Press of Mississippi. pp. 525–528. 
  6. ^ Anonymous (2014-07-16). "Lefteye Flounder". Outdoor Alabama. Retrieved 2017-04-27. 
source: http://en.wikipedia.org/wiki/Paralichthys_lethostigma

 

More info on Paralichthys lethostigma

(also Southern Flounder) :

Texas Parks and Wildlife

Fishes of Texas

Nature Serve

 

 

 

 

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