Atlantic Needlefish

Atlantic Needlefish by Inked Animal
Atlantic Needlefish | Strongylura marina

Atlantic Needlefish Gyotaku by Inked Animal

 

Info via Wikipedia:

Strongylura marina
Atlantic Needlefish by Inked Animal
Conservation status
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 bottom-water 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.[1][2] 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.[3] 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.[4]S. marina has also been introduced and now inhabits parts of the Tennessee River drainage throughout Alabama and Tennessee.[5]

Ecology

As juveniles, the diet of S. marina consists of 70% shrimp, mysids and amphipods and 30% fish, while adults are exclusively piscivorous.[6][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.[2]

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.[1]

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.[10]

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.[10]

References

  1. ^ 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.
  2. ^ a b Collette, B B. 1968. Strongylura timucu (Wallbaum) - A valid species of Western Atlantic needlefish. Copeia 1: 189-192.
  3. ^ Berry, F. H. & Rivas, L. R. 1962. Data on six species of needlefishes (Belonidae) from the western Atlantic. Copeia 1962:152-160.
  4. ^ 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.
  5. ^ Boschung, H. T. 1992. Catalogue of freshwater and marine fishes of Alabama. Alabama Museum of Natural History Bulletin 14:1-266.
  6. ^ 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. Trans. Amer. Fish. Soc. 102:511-540.
  7. ^ Carr, E. S. & Clayton A. Food habits of juvenile marine fishes occupying seagrass beds in the estuarine zone near Crystal River, Florida. Trans. of the American Fisheries Sciences 102: 511-540.
  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.
  10. ^ a b 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.

External links

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

Guadalupe Bass (Williamson County, TX)

Guadalupe Bass (Williamson County, TX) by Inked Animal

Guadalupe Bass (Williamson County, TX) by Inked Animal

Guadalupe Bass | Micropterus treculii

collected March 2012, Brushy Creek, Williamson County, Texas, USA
printed March 2012
India ink on paper

 

We’ve printed this species  before – see our previous versions with a different specimen. We figured we’d try it again after running across this beautiful specimen in Brushy Creek just north of Austin.  See the photo below. It’s colors and patterns have changed a bit since we collected it. At that time it had some of the vertical barring typical of Guadalupe bass.

Guadalupe Bass (Williamson County, TX) by Inked Animal

Guadalupe Bass (Williamson County, TX) by Inked Animal

I really like the look of specimens with ink on them. All color is hidden and you start to notice things you wouldn’t otherwise. In this case the ink and the angle of the reflecting light allows you to see the individual scales in great detail. Notice how small the cheek scales are compared to the body scales. I recently learned that this is a good character for distinguishing Guadalupe bass and spotted bass from the largemouth bass which has cheek scales similar in size to the body scales.

Guadalupe Bass (Williamson County, TX) by Inked Animal

Alligator Gar

Alligator Gar by Inked Animal

Alligator Gar | Atractosteus spatula

 

We have to give some credit to Robby Maxwell here.  He aided with both the capture and immortalization of this beast.  It wasn’t the largest Alligator gar we’d seen, but large enough and a great time to catch. Robby, myself, and a large Texas State University crew wrangled this specimen as part of my master’s thesis working on the Brazos River watershed, Texas.  He’ll have to confirm, but I believe we caught this in the winter of 2008 in Brazos Bend State Park under the watchful gaze of park authority and many reptilian versions of alligators. This gyotaku print will surely be popular among many fish fanatics that I know who, justifiably so, respect the hell out of this fish. This species is known to get massive, one of the largest freshwater predators in the world.  Its even been featured on River Monsters I believe.  Its also a very old lineage of fish with a special version of a circulatory system that relies on oxygen brought in not just through its gills, but also through its toothy mug into its air bladder where gas exchange occurs.  For this reason, gar are one of those few fish that you can actually drown!


Alligator Gar info via Wikipedia:

Alligator gar
Alligator Gar by Inked Animal
Alligator gar in an aquarium
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Infraclass: Holostei
Order: Lepisosteiformes
Family: Lepisosteidae
Genus: Atractosteus
Species: A. spatula
Binomial name
Atractosteus spatula
(Lacépède, 1803)
Synonyms

Lepisosteus spatula Lacépède, 1803
Atractosteus adamantinus Rafinesque, 1818

Alligator Gar by Inked Animal
Preserved display of an alligator gar head

Alligator gars, Atractosteus spatula, are ray-finned euryhaline fishes related to bowfin in the infraclass Holostei (ho'-las-te-i). The fossil record traces the existence of alligator gars back to the Early Cretaceous over a hundred million years ago. They are the largest in the gar family, and among the largest freshwater fishes in North America. Gars are often referred to as "primitive fishes", or "living fossils" because they have retained some morphological characters of their earliest ancestors, such as a spiral valve intestine which is also common to the digestive system of sharks, and they can breathe both air and water. Their common name was derived from their resemblance to American alligators, particularly their broad snout and long sharp teeth. Anecdotal scientific reports suggest that alligator gars can grow to 10 ft (3.0 m) and weigh 300 lb (140 kg), however in 2011 the largest alligator gar ever caught and officially recorded was 8 ft 5 14 in (2.572 m) long, weighed 327 lb (148 kg), and was 47 in (120 cm) around the girth. Their bodies are torpedo shaped, usually brown or olive fading to a lighter gray or yellow ventral surface. They do not have scales like other fishes, rather they are armored for protection against predation with hard, enamel-like, jagged diamond-shaped ganoid scales that are nearly impenetrable. Unlike other gar species, mature alligator gars have a dual row of large sharp teeth in the upper jaw which they use for impaling and holding prey. They are stalking, ambush predators that are primarily piscivores, but will also ambush and eat water fowl and small mammals that may be floating on the surface.

Alligator gars have been extirpated from much of their historic range through habitat destruction, indiscriminate culling, and unrestricted harvests. Populations are now located primarily in the southern portions of the United States extending into Mexico. They are considered euryhaline because they can adapt to varying salinities ranging from freshwater lakes and swamps to brackish marshes, estuaries, and bays along the Gulf of Mexico.

For nearly a half-century, alligator gars were considered "trash fish",[1] or a "nuisance species" that were detrimental to sport fisheries, and therefore targeted for elimination by state and federal authorities in the United States, but the last ten years has seen a greater emphasis placed on the importance of alligator gars to the ecosystems they inhabit. As a result, they were afforded protection by restricted licensing. They are also protected under the Lacey Act which makes it illegal to transport fish in interstate commerce when in violation of state law or regulation. Several state and federal resource agencies are monitoring populations in the wild, and have initiated outreach programs to educate the public. Alligator gars are being cultured in ponds, pools, raceways and tanks by federal hatcheries for mitigation stocking, by universities for research purposes, and in Mexico for consumption.[2]

Anatomy and physiology

Alligator gars are the largest species of gar, and among the largest freshwater fishes found in North America. Mature alligator gars commonly measure 6 ft (1.8 m) in length, and weigh over 100 lbs. (45kg). However, anecdotal reports suggest they can grow up to 10 ft (3m) in length, and weigh as much as 350 lbs. (159 kg).[3] The largest alligator gar officially recorded was inadvertently caught in the net of fisherman Kenny Williams of Vicksburg, Mississippi while he was fishing the oxbow lakes of the Mississippi River on February 14, 2011. Williams was pulling up his net on Lake Chotard expecting to find buffalo fish, but instead discovered a large alligator gar tangled in his net. The gar was 8 ft 5 14 in (2.572 m) long, weighed 327 lb (148 kg), and its girth was 47 in (120 cm). According to wildlife officials, the fish was estimated to be somewhere between 50 and 70 years old. Williams donated it to the Mississippi Museum of Natural Science in Jackson where it will remain on display.[4][5]

Alligator Gar by Inked Animal
Gill of a juvenile gar

All gars have torpedo-shaped bodies, but some distinguishing characteristics of adult alligator gars include their large size, heavy bodies, broad heads, short broad snouts, large sharp teeth and double row of teeth on their upper jaw. They are usually brown or olive fading to a lighter gray or yellow ventral surface. The dorsal and anal fins are positioned toward the back of their bodies, and their caudal fin is abbreviate-heterocercal, or non-symmetrical.[3]

Alligator gars have gills, but unlike other fishes they also have a highly vascularized swim bladder lung that supplements gill respiration. The bladder not only provides buoyancy but also enables them to breathe in air which is why they are able to inhabit bodies of water in which most other fishes would die of suffocation. The swim bladder is connected to their foregut by a small pneumatic duct which allows them to breathe or gulp air when they break the surface,[6] an action that is seen quite frequently on lakes in the southern United States during the hot summer months. The scales of alligator gars are not like the scales of other fishes; their bodies are protected by overlapping, enamel-like ganoid scales that are diamond-shaped with jagged edges and composed of a hard inner layer of bone and an outer layer of ganoin that is nearly impenetrable.[7]

Taxonomy and evolution

Lacépède first described the alligator gar in 1803. The original name was Lepisosteus spatula, but was later changed by E.O. Wiley in 1976 to Atractosteus spatula in order to recognize two distinct extant taxon of gars. Synonyms of Atractosteus spatula include Lesisosteus [sic] ferox (Rafinesque 1820), and Lepisosteus spatula (Lacepede 1803). Fossils from the order Lepisosteiformes have been collected in Europe from the Cretaceous to Oligocene periods, in Africa and India from the Cretaceous, and in North America from the Cretaceous to recent times. Lepisosteidae is the only extant family of gar which has seven species all located in North and Central America.[3] The fossil record traces the existence of alligator gars back to the Early Cretaceous over a hundred million years ago.[8][9] Despite being a highly evolved species, alligator gars are often referred to as "primitive fishes", or "living fossils"[10][11] because they have retained a few morphological characteristics of their earliest ancestors with seemingly little to no apparent changes, such as a spiral valve intestine which is also common to the digestive system of sharks, an abbreviate-heterocercal tail, and a swim bladder lung for breathing in both air and water.[3][7][12]

Feeding behavior

Alligator gars are stalking, ambush predators

Alligator gars are relatively passive, seemingly sluggish solitary fish, but voracious ambush predators. They are opportunistic night predators and are primarily piscivores, but they will also ambush and eat water fowl and small mammals that may be floating on the surface. Their method of ambush is to float a few feet below the surface, and wait for unsuspecting prey to swim within reach. They lunge forward, and with a sweeping motion grab their prey, impaling it on their double rows of sharp teeth.[7]

Diet studies have shown alligator gars to be opportunistic piscivores, and even scavengers depending on the availability of their preferred food source. They occasionally ingest sport fishes, but the majority of stomach content studies suggest they feed predominately on forage fishes such as gizzard shad as well as invertebrates, and water fowl. Diet studies have also revealed fishing tackle and boat engine parts in their stomachs.[13][14]

Spawning

As with most ancestral species, alligator gars are long living, and sexually late maturing. Most females do not reach sexual maturity until after their first decade of life while males reach sexual maturity in half that time. The conditions must be precise for a successful spawning to occur. Preparation for spawning begins in the spring with the extended photoperiod and rising water temperatures, but flooding is also necessary to trigger the event. When rivers rise and spread over the floodplain, they create oxbow lakes and sloughs, and inundate terrestrial vegetation which in turn provides protection and a nutrient rich habitat for larval fishes, and fry. Once the water temperature has reached 68 to 82 °F (20 to 28 °C), and all the other criteria are met, gars will move into the grassy, weed-laden shallows to spawn.[15][16]

Actual spawning occurs when a collection of males gather around gravid females, and begin writhing, twisting, bumping into and slithering over the tops of females, an activity which triggers the release of eggs. Males release clouds of milt to fertilize the eggs as they are released into the water column.[15] The sticky eggs then attach to submerged vegetation, and development begins. It takes only a few days for the eggs to hatch into larval fish, and another ten days or so for the larval fish to detach from the vegetation and start moving about as young fry.[16] Egg production is variable, and believed to be dependent on the size of the female. A common formula used for predicting the volume of eggs a female can produce is 4.1 eggs/gram of body weight which gives an average of about 150,000 eggs per spawn. The eggs of alligator gars are bright red and poisonous to humans if ingested.[7]

Distribution

Alligator Gar by Inked Animal
Alligator gar caught in Moon Lake by Bill Valverde, January 1, 1951, Rio Grande, Texas

Natural range

Alligator gars use a wide variety of aquatic habitats, but most are found in the Southern United States in reservoirs and lakes, in the backwaters of lowland rivers, and in the brackish waters of estuaries, bayous and bays. They have occasionally been seen in the Gulf of Mexico.[7] In Texas and Louisiana it is common to see large gars breaking the surface in reservoirs, bayous, and brackish marshes. They are found throughout the lower Mississippi River Valley and Gulf Coast states of the Southern United States and Mexico as far south as Veracruz, encompassing the following states in the United States: Texas, Oklahoma, South Carolina, North Carolina, Virginia, Louisiana, Kentucky, Mississippi, Alabama, Tennessee, Arkansas, Missouri, Florida, and Georgia.[17] Reports suggest alligator gars were once numerous throughout much of their northern range, however valid sightings today are rare, and may occur once every few years.[3] Records of historical distribution indicate alligator gars once inhabited regions as far north as central Kansas, Nebraska, Ohio, Iowa, and west-central Illinois where they are now listed as extirpated. The most northerly verified catch was in Meredosia, Illinois in 1922.[18]

Outside natural range

A few notable sightings of alligator gars have been reported outside North America. In November 2008, an alligator gar measuring 5.2 to 6.4 ft (1.6 to 2.0 m) was caught in the north of Esenguly, Turkmenistan by two officials of Turkmenistan Fishery Protection.[19]

On September 4, 2009 a 3 ft 3 in (0.99 m) alligator gar was found in Tak Wah Park in Tsuen Wan, Hong Kong. Over the next two days, at least 16 other alligator gars, the largest measuring 4.9 ft (1.5 m), were found in ponds in public parks in Hong Kong.[20] Nearby residents reported the alligator gars had been released into the ponds by aquarium hobbyists, and had lived there for several years. However, after a complaint made by a citizen who falsely identified alligator gars as crocodiles, the use of terms like "horrible man-eating fish" had begun appearing in the headlines of some major local newspapers. Officials with Leisure and Cultural Services in Tak Wah Park removed all the alligator gars from the ponds because they were concerned the large, carnivorous fish might harm children.[21] It is not unusual for the large sharp teeth and outward appearance of alligator gars to precipitate unreasonable fear in those unfamiliar with the species. Sensationalized reports have contributed to the misconception of predatory attacks by alligator gars on humans even though none of the reports have been confirmed. [22]

On January 21, 2011, an alligator gar measuring 4 feet 11 inches (1.50 m) was caught in a canal in Pasir Ris, Singapore by two recreational fishermen. The fish was taken to a nearby pond where the owner confirmed it was an alligator gar rather than an arapaima as the men had initially thought.[23]

Human utilization

Early history

Native Americans in the south, and Caribbean peoples used the alligator gar's ganoid scales for arrow heads, breastplates, and as shielding to cover plows. Early settlers tanned the skins to make a strong, durable leather to cover their wooden plows, make purses, and various other items. Gar oil was also used by the people of Arkansas as a repellent for buffalo-gnats.[13]

For nearly half a century, alligator gars were considered "trash fish",[1] or a "nuisance species" by state and federal authorities who targeted them for elimination to protect game fish populations,[24] and to prevent alleged attacks on humans, a claim that remains unsubstantiated with the exception of occasional injuries sustained from captured alligator gars thrashing around on the decks of boats.[7] Fishermen participated in the slaughter of thousands of alligator gars believing they were providing a great service. In 1995, KUHT channel 8, a member PBS television station located on the campus of the University of Houston in Texas, distributed and broadcast the first video documentary ever produced on alligator gar. The documentary, "Alligator Gar:Predator or Prey?", debuted nationally in prime time during the July Sweeps, and according to the Nielsen rating report provided to KUHT, was the number one rated program of the evening.[7] The documentary focused on the physiology and life cycle of alligator gars, addressed the destruction of habitat, the unregulated culling and over harvesting of alligator gars from various lakes in Texas and Louisiana, and expressed concerns for the future of the species at a time when it was still considered a "trash fish".[7] A decade passed before any significant action was taken to protect and preserve the remaining populations of alligator gar in the United States. The Missouri Department of Conservation has since partnered with Tennessee, Arkansas, Kentucky, Illinois, Alabama, Mississippi, Texas, Oklahoma, and Louisiana in restoration and management activities.[13]

Alligator Gar by Inked Animal Alligator Gar by Inked Animal Alligator Gar by Inked Animal Alligator Gar by Inked Animal Alligator Gar by Inked Animal Alligator Gar by Inked Animal
Ganoid scale jewelry Ganoid scale earrings 1995 Choke Canyon Harvest On site processing Market display of gar fillets Fillets grilled, and crab boiled

Sport fish

Alligator Gar by Inked Animal
6 ft (1.8 m) 129 lb (59 kg) alligator gar caught by K. Kirkland, Brazos River, Texas, 1991

The long time public perception of alligator gars as "trash fish", or a "nuisance species" has changed with increasing national and international attention on the species as a sport fish which some have attributed to features on popular television shows. Oklahoma, Texas, Arkansas, Mississippi, and Louisiana allow regulated sport fishing of alligator gars. Texas has one of the best remaining fisheries for alligator gars, and in concert with its efforts to maintain a viable fishery, imposed a one-per-day bag limit on them in 2009.[25] The Texas state record, and world record for the largest alligator gar caught on rod and reel is 279 lb (127 kg), taken by Bill Valverde on January 1, 1951 on the Rio Grande in Texas.[26] Alligator gars are also quite popular among bowfishers because of their large size, trophy potential, and fighting ability. The Texas state bowfishing record was set In 2001 by Marty McClellan with a 290 pounds (130 kg) alligator gar from the Trinity River. The all-tackle record was a 302 pounds (137 kg) alligator gar caught on a trotline in 1953 by T.C. Pierce, Jr. In 1991, fishing guide, Kirk Kirkland, anecdotally reported catching an alligator gar measuring 9 feet 6 inches (2.90 m) on rod and line from the Trinity River. [27]

Commercialization and aquaculture

Declining populations of alligator gars throughout their historic range has resulted in the need to monitor wild populations and regulate commercial harvests. Alligator gars have a high yield of white meat fillets and a small percentage of waste relative to body weight. The meat is sold to wholesale distributors, and also sold retail by a few supermarkets with prices starting at around $3.00/lb. Fried gar balls, grilled fillets, and fillets boiled in water with crab boil seasoning are popular dishes in the south. There is also a small cottage industry that makes jewelry out of ganoid scales, and tans gar hides to produce leather for making lamp shades, purses, and a host of novelty items.[7][13]

Atractosteus gars, including alligator gars, tropical gars, and Cuban gars are considered good candidates for aquaculture particularly in developing regions where their rapid growth, disease resistance, easy adaptation to artificial feeds as juveniles, and ability to tolerate low water quality are essential. Their ability to breathe in both air and water eliminates the need for costly aeration systems and other technology commonly used in aquaculture. In the Southern United States, as well as in parts of Mexico and Cuba, broodstocks have already been established, and are being maintained in their respective regions where they already are a popular food fish.[28]

Aquaria

Alligator gar maneuvering with pectoral fins in large zoo aquarium

Despite the large size alligator gars can attain, they are kept as aquarium fish, though many fish labeled as "alligator gar" in the aquarium trade are actually smaller species. Alligator gars require a very large aquarium or pond, and ample resources in order for them to thrive in captivity. They are also a popular fish for public aquaria, and zoos. It is illegal in many areas to keep alligator gars as pets, but they will occasionally show up in fish stores. Alligator gars are highly prized and sought after for private aquaria, particularly in Japan. According to some reports, large alligator gars could fetch as much as US$40,000 in what some consider the "Japanese black market".[29] In June 2011, three men from Florida and Louisiana were indicted on charges of illegally removing wild alligator gars from the Trinity River in Texas, and attempting to ship them to Japan for private collectors. The indictments resulted from an undercover sting operation by special agents with the U.S. Fish & Wildlife Service, the Texas Parks and Wildlife Department, and the Florida Fish and Wildlife Conservation Commission.[30] The charges included violations of three separate provisions of the Lacey Act, specifically conspiracy to submit a false label for fish transported in interstate commerce; conspiracy to transport fish in interstate commerce in violation of state law or regulation; and conspiracy to transport and sell fish in interstate commerce in violation of state law or regulation.[31] Two of the conspirators entered guilty pleas to one count, and the government dropped the other two charges against them. A third conspirator went to trial on all three counts, was acquitted on one count, and found guilty on two. The district court sentenced him to serve nine months in prison followed by one year of supervised release.[32] The case was appealed, and on April 15, 2014, the appellate court affirmed the judgment of the district court.[33]

References

  1. ^ a b Tony Brady (August 2013). "Fleur De Lis Fisheries". US Fish & Wildlife Service. p. 2. 
  2. ^ S.E. Lochmann, Brandon W. Baker, Kyle T. Rachels, and Brett A. Timmons. "New Research". Aquaculture and Fisheries Center. University of Arkansas at Pine Bluff. Retrieved June 18, 2014. 
  3. ^ a b c d e Nathaniel Goddard. "Alligator Gar". FLMNH Ichthyology Department. Retrieved April 19, 2014. 
  4. ^ "Vicksburg Man Catches 327 Lb. Alligator Gar". WAPT News. February 18, 2011. 
  5. ^ Chad Love (February 23, 2011). "World Record Alligator Gar Pulled From Mississippi Lake Tangled in Fisherman's Net". Field & Stream. Retrieved April 19, 2014. 
  6. ^ "Biology of Fishes-Fish/Biol 311". Swimbladder. University of Washington. Retrieved August 2, 2014. 
  7. ^ a b c d e f g h i B. Wills. "Alligator Gar". Earthwave Society. Retrieved April 14, 2014. 
  8. ^ Daniel E. Schwartz, Peter J. Allen (December 2013). "Comparative biochemistry and physiology. Part A, Molecular and integrative physiology". Mississippi State University Dept. of Wildlife, Fisheries and Aquaculture. 
  9. ^ American Society of Naturalists. The American Naturalist 35. University of Chicago Press. Retrieved May 30, 2014. 
  10. ^ Melvin L. Warren, Jr., Brooks M. Burr. Freshwater Fishes of North America. Johns Hopkins University Press. p. 250, Vol 1. 
  11. ^ Mayor, Adrienne (2005). Fossil Legends of the First Americans. Princeton University Press. p. 38. ISBN 9781400849314. 
  12. ^ Graham, Jeffrey B. (1997). Air-Breathing Fishes: Evolution, Diversity, and Adaptation. Academic Press. pp. 1–10. ISBN 0-12-294860-2. 
  13. ^ a b c d "Missouri Alligator Gar Management and Restoration Plan". Missouri Department of Conservation Fisheries Division. January 22, 2013. Retrieved July 2014. 
  14. ^ David L. Buckmeier (July 31, 2008). "Life History and Status of Alligator Gar (Atractosteus spatula), with Recommendations for Management". Heart of Hills Fisheries Science Center. Texas Parks and Wildlife Department. p. 5. Retrieved July 7, 2014. 
  15. ^ a b BBest Biological Subcommittee (November 2, 2009). "BBest Recommendations Report". Sabine/Neches BBest Biological Overlay Approach. Texas Commission on Environmental Quality. p. 8. Retrieved July 7, 2014. 
  16. ^ a b Shannon Thompkins (April 19, 2014). "Once a nuisance, alligator gar increasingly protected". Houston Chronicle. 
  17. ^ "Alligator Gar Technical Committee". Southern Division of the American Fisheries Society. Retrieved May 17, 2013. 
  18. ^ Poly, William J. (2001). "Distribution of the Alligator Gar, Atractosteus spatula (Lacépède, 1803), in Illinois". Transactions of the Illinois State Academy of Science 94 (3): 185–190. 
  19. ^ "Hazar Deňziniň Türkmen Kenarynda Amerikan Sowutly Çortanyň Tutulmagynyň Ilkinji Wakasy" (in Turkish). Türkmenistanyò Tebigaty goramak ministrligi. Retrieved May 17, 2013. 
  20. ^ "Monster exotic fish found in Hong Kong ponds". AFP. September 5, 2009.
  21. ^ Amy Nip (January 10, 2010). "Feared in public ponds, admired behind glass". South China Morning Post. 
  22. ^ Spitzer, Mark. "When Gars Attack". Southest Missouri State University. Retrieved July 21, 2014. 
  23. ^ "Friends catch 1.5m 'monster' fish from Pasir Ris canal after long struggle". The Straits Times. January 21, 2011. 
  24. ^ Echevarria, Carlos (February 5, 2013). "Alligator Gar, Atractosteus spatula". Warm Springs National Fish Hatchery. US Fish & Wildlife Service. Retrieved July 7, 2014. 
  25. ^ "Alligator Gar". Texas Parks and Wildlife Department. Retrieved April 21, 2014. 
  26. ^ "State Freshwater Records: Rod and Reel". Texas Parks & Wildlife. Retrieved May 17, 2013. 
  27. ^ "Big Fish Stories Can Have Happier Endings". Texas Parks & Wildlife. May 16, 2011. 
  28. ^ Alfaro, Roberto M., Gonzales, Carlos A., Ferrara, Allyse (2008). "Gar biology and culture: status and prospects". Chapter 39. Aquaculture Research. pp. 748–763. Retrieved July 7, 2014. 
  29. ^ Horswell, Cindy (June 17, 2011). "Indictments accuse 3 of taking alligator gar fish out of Trinity". Houston Chronicle. 
  30. ^ Jon Berstein (October 15, 2011). "Monster fish tale: Alligator gar sting ends in conviction". SunSentinel. 
  31. ^ "Accused alligator gar smugglers busted in trinity river operation". ABC 9 KTRE. 2011. 
  32. ^ "Monthly Bulletin". Regional EnvironmentalEnforcement Association. October 2012. Retrieved April 2014. 
  33. ^ "Opinions". U.S. Court of Appeals. April 15, 2014. 

External links

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

Nature Impressions: Riusuke Fukahori’s genius

goldfish-3-600x398

Nature Impressions:  Riusuke Fukahori’s genius by Inked AnimalThis is easily the best thing I’ve found for this blog series so far.  This is why in my opinion:

1. It deals with fish (big plus in my book)

2. It is a novel medium (to me at least)

3. It is a beautiful balance of art and nature (prerequisite for sharing).

 

 

Fukahori’s work is a mind bending expression that attempts to capture nature’s unique moments.  What I see in this art is reminiscent of what one might experience when gazing into a stream along its bank, everything frozen in time.  He has mastered painting images into 3D blocks of resin, painting a layer, adding resin, painting a layer, adding resin, and so on.  The effect is stunningly realistic scenes of fish swimming in schools in small containers. Most of his paintings are of goldfish or carp. See our Asian Carp gyotaku, Common Carp, for an alternate version of an artistic impression of this fish. The artist’s website is here.

Images from Dominic’s pics on Flickr

Here’s a video of him in action; enjoy

Inaugural Nature Impressions Blog Post – Nature Printing Society

So as part of this website, Adam and I want to not only share our unique version of handmade impressions of nature, we want to search the web for others doing nature inspired works of art.  Much of my art, and I know much of Adams (www.AdamEspeleeCohen.com & www.Silverfish-Art.com) is inspired by the natural world as well as by others artists that use nature as a muse.

My hopes with this part of the blog is to supplement our work with others, to create a sort of nature-art digest.  Maybe once a month or once every two months Adam and I would do a print, but between those, I could introduce readers here to some really cool art being done elsewhere.

So to start, I want to talk about the Nature Printing Society, which admittedly we just joined. We signed up to be able to be associated and co-mingle, at least on the inter-web, with like minded artists.  Check out the members gallery for many very cool prints from a great group of talented nature printing enthusiasts. Here is a small sampling of the member artists with some prints that caught my eye.

Jeanette Jobson

Inaugural Nature Impressions Blog Post   Nature Printing Society by Inked Animal

"Red Fish on batiked paper" by Jeanette Jobson; Image courtesy of www.jeanettejobson.com

 

 

 

 

 

 

 

 

Dr. Ed  Guttery

Inaugural Nature Impressions Blog Post   Nature Printing Society by Inked Animal

"Jack Crevalle" by Dr. Ed Guttery; Image Courtesy of www.egutterygyotaku.com

 

 

 

 

 

 

 

 

Rachel Ramirez

Inaugural Nature Impressions Blog Post   Nature Printing Society by Inked Animal

"Polvo em tinta" by Rachel Ramirez; image courtesy of http://the-artists.org/portfolio/rachel-ramirez

 

 

 

 

 

 

 

 

 

 

 

 

Micheal Reimer

Inaugural Nature Impressions Blog Post   Nature Printing Society by Inked Animal

"Rock Bass" by Michael Reimer Gyotaku; image courtesy of www.michaelreimer.com

 

 

 

 

 

 

 

 

 

Guadalupe Bass

Guadalupe Bass by Inked Animal

Guadalupe Bass | Micropterus treculii

The state fish of Texas!  Since 1989. This baby is one of around 10(?) bass in America, and is only found in central Texas.  Adam and I have collected fish together all over the state, and at least for me, this fish is one of those that when you catch it, you appreciate it. Especially a decent size one like this specimen.  This fish is special for many reasons, among them is that its only found in Texas, and its in danger of being bred out by the native spotted (Micropterus punctulatus) and large mouth (Micropterus salmoides) basses as well as the invasive small mouth bass (Micropterus dolomieu). Texas Parks and Wildlife department list it as a State Threatened fish.

I think the Guadalupe Bass should be the grand prize of any freshwater fisherman in Texas.  I’ve got a good friend with a fly fishing blog specializing in central Texas fishing, he has many maps and posts about catching this special fish.  Check him out at diefische.

We hope you like our Gyotaku of the Guadalupe Bass. Notice the detail of the scales behind the eye, good stuff.  This is our only one for the G.bass so far, and we’re determined to do some more with other specimens once they’re caught.  We still need to get an open mouth bass print! But that will probably be reserved for the large mouth….which is also still to come.


 

Guadalupa Bass info via Wikipedia:

Guadalupe bass
Guadalupe Bass by Inked Animal
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Centrarchidae
Genus: Micropterus
Species: M. treculii
Binomial name
Micropterus treculii
(Vaillant & Bocourt, 1883)

The Guadalupe bass (Micropterus treculii) is a rare species of fish endemic to the U.S. state of Texas, where it also is the official state fish. It is restricted to creeks and rivers (including the Guadalupe River, hence the name Guadalupe bass), and was formerly listed as vulnerable, but IUCN currently considers the data insufficient to determine its status.[1] Today, most fly fishermen and anglers practice catch-and-release techniques to improve fish populations. The Guadalupe bass is often difficult to distinguish from the smallmouth bass or spotted bass, and the first is known to hybridize.

Description and range

Guadalupe bass, like most black bass, are lime to olive green in color, this particular species being lighter in shade usually in river specimens. They have a lateral line covered in mostly separate diamond shaped or circular spots, which with age fades from black to olive. There are also many smaller diamond marks scattered on the back which are less distinguished than the ones on the lateral line. Its physical traits are very similar to the spotted bass (i.e. small mouth that doesn't extend past the eye, sleek figure, etc.) with one exception: the green coloring tends to extend lower on the body past the lateral line than their cousins. So far the record is 3.71 lbs (3 lbs 11.360 oz.), caught by Dr. Bryan Townsend of Austin in 2014. The fish is only found in Edward's Plateau in central Texas. Its main habitats are the San Marcos, Colorado, and Guadalupe rivers. They can also be found in run-off creeks such as Barton Creek, Onion Creek, San Gabriel river, and The Comal river. The species has also been farm raised and stocked in the Llano river.

Threats and predators

The Guadalupe bass has almost no predators. In fact its main threat is not predation, but hybridization with the introduced smallmouth bass. The two species are very closely related and in some rivers almost half the Guads are hybrids. The Texas Parks and Wildlife Dept. stated it will likely stock many bass in the future to beat out the hybrid population. This will be a pilot for several other areas where rare spotted bass sub-species are having the same problems.

Habitat

Typically, Guadalupe bass are found in streams and reservoirs; they are absent from extreme headwaters. The Guadalupe bass prefer flowing waters of streams within native variety, and use covers like large rocks, cypress knees or stumps for refuge.

Diet

The fish (especially juveniles and very old fish), unlike other bass, have an inclination towards insects. Guadalupe bass at their predatory peak prefer larger bait fish such as shad and small bass or bluegill.

Fishing

While almost unheard of elsewhere, the Guadalupe bass is very popular among fishermen in central Texas. It is cherished for its long tough fights, in which it manipulates the current and its unusually strong muscles, and beautiful colors which tend to be more natural and bright than those of spotted bass. Its preference for strong current and its large diet of insects earned it the name "Texas Trout" and made it popular for fly fishermen. It fights similarly to both smallmouth bass and Rainbow Trout—making long runs and manipulating current, but also making sharp turns and attempting to entangle the line on structures, and even making large jumps like both species. Altogether, it makes a very satisfying fight, and it can be difficult and extremely fun to land a 2+ lb. fish.

If fishing in a larger river, one will most likely find large fish in deep pools with some current, scavenging off whatever the current brings, and in the shallows, looking for fry, bait fish, frogs, the occasional rodent, and hatching insects if in the right season. Smaller fish are found in fast current behind riffles, eating passing nymphs that were sucked in and small minnows eating the same. Due to their preference for small fish and insects, fly fishermen are at a large advantage.

References

  1. ^ a b Gimenez Dixon, M. (1996). "Micropterus treculii". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 12 June 2014. 

Sources

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

Blacktip Shark 3

 

Blacktip Shark 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
Blacktip Shark 3 by Inked Animal
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha
Order: Carcharhiniformes
Family: Carcharhinidae
Genus: Carcharhinus
Species: C. limbatus
Binomial name
Carcharhinus limbatus
(J. P. Müller & Henle, 1839)
Blacktip Shark 3 by Inked Animal
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 1–10 pups every other year. Young blacktip sharks spend the first months of their lives in shallow nurseries, and grown females will 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 International Union for Conservation of Nature (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

Blacktip Shark 3 by Inked Animal
The blacktip shark has black markings on most of its fins.

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 2 symphysial teeth (at the jaw midline) in the upper jaw and 1 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; there is no ridge running 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 (9.0 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

Blacktip Shark 3 by Inked Animal
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 southern China to northern Australia, including 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 (100 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.[10]

Biology and ecology

The blacktip shark is an extremely fast, energetic predator that is usually found in groups of varying size.[3] There is segregation by sex and age; adult males and non-pregnant 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.[11] Predator avoidance may also be the reason why juvenile blacktips do not congregate in the areas of highest prey density in the bay.[12] 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][13][14] This species is also parasitized by nematodes in the family Philometridae, which infest the ovaries.[15]

Behavior

Blacktip Shark 3 by Inked Animal
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 to 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.[16] The speed attained by the shark during these jumps has been estimated to average 6.3 m/s (21 ft/s).[17]

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; it is possible that one of these behaviors is derived from the other.[18]

Feeding

Fish make up some 90% of the blacktip shark's diet.[19] 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).[19] Off South Africa, jacks and herring are the most important prey.[20] Hunting peaks at dawn and dusk.[19] 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 4–7 (range 1–10) 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.[21][22] 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.[21][23]

Mating occurs from spring to early summer, and the young are born at around the same time the following year after a gestation period of 10–12 months.[1] Females have one functional ovary and two functional uteruses; each uterus is separated into compartments with a single embryo inside each.[24] 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.[10] 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.[10][24] The mortality rate in the first 15 months of life is 61–91%, with major threats being predation and starvation.[25] The young remain in the nurseries until their first fall, at which time they migrate to their wintering grounds.[10]

The growth rate of this species slows with age: 25–30 cm (10–12 in) in the first six months, then 20 cm (8 in) a year until the second year, then 10 cm (4 in) a year until maturation, then 5 cm (2 in) a year for adults.[26][27] 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,[10] 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,[26][28] 1.5 m (4.9 ft) and 1.6 m (5.2 ft) respectively off South Africa,[29] and 1.7 m (5.6 ft) and 1.8 m (5.9 ft) respectively off North Africa.[24] The age at maturation is 4–5 years for males and 7–8 years for females.[26][28] The lifespan is at least 12 years.[1]

In 2007, a 9-year-old female blacktip shark at the Virginia Aquarium & 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.[30]

Human interactions

Blacktip Shark 3 by Inked Animal
The blacktip shark usually poses little danger to divers.

There are reports of blacktip sharks showing curiosity towards divers, but remaining at a safe distance. Under most circumstances, this timid shark is 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.[31] 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, South China Sea, and off northern Australia.[27]

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 (IGFA). 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.[27] The International Union for Conservation of Nature (IUCN) has assessed the blacktip shark as Near Threatened, as its low reproductive rate renders it vulnerable to overfishing.[32] 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 (LCS) category of the US National Marine Fisheries Service (NMFS) Atlantic shark Fisheries Management Plan (FMP). No conservation plans specifically for this species have been implemented.[27]

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. and 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. ^ 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. 
  11. ^ Heupel, M.R. and Simpfendorfer, C.A. (2005). "Quantitative analysis of aggregation behavior in juvenile blacktip sharks". Marine Biology 147: 1239–1249. doi:10.1007/s00227-005-0004-7. 
  12. ^ Heupel, M.R. and 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: 543–550. doi:10.1071/MF01132. 
  13. ^ Bullard, S.A., Frasca, A. (Jr.) and 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. 
  14. ^ Bullard, S.A., Benz, G.W. and Braswell, J.S. (2000). "Dionchus postoncomiracidia (Monogenea: Dionchidae) from the skin of blacktip sharks, Carcharhinus limbatus (Carcharhinidae)". Journal of Parasitology (86): 245–250. 
  15. ^ Rosa-Molinar, E. and 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. 
  16. ^ Riner, E.K. and 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. 
  17. ^ 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 1578268. PMID 16849197. 
  18. ^ Ritter, E.K. and Godknecht, A.J. (February 1, 2000). "Agonistic Displays in the Blacktip Shark (Carcharhinus limbatus)". In Ross, S. T. Copeia 2000 (1): 282–284. doi:10.1643/0045-8511(2000)2000[0282:ADITBS]2.0.CO;2. 
  19. ^ 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.
  20. ^ Dudley, S.F.J. and 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. 
  21. ^ a b Keeney, D.B., Heupel, M., Hueter, R.E. and 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: 1039–1046. doi:10.1007/s00227-003-1166-9. 
  22. ^ 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. 
  23. ^ Keeney, D.B., Heupel, M.R., Hueter, R.E. and 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. 
  24. ^ a b c Capapé, C.H., Seck, A.A., Diatta, Y., Reynaud, C.H., Hemida, F. and Zaouali, J. (2004). "Reproductive biology of the blacktip shark, Carcharhinus limbatus (Chondrichthyes: Carcharhinidae) off West and North African Coasts". Cybium 28 (4): 275–284. 
  25. ^ Heupel, M.R. and 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. 
  26. ^ a b c Branstetter, S. (Dec 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. 
  27. ^ a b c d Fowler, S.L., Cavanagh, R.D., Camhi, M., Burgess, G.H., Cailliet, G.M., Fordham, S.V., Simpfendorfer, C.A. and 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. 
  28. ^ a b Killam, K.A. and Parsons, G.R. (May 1989). "Age and Growth of the Blacktip Shark, Carcharhinus limbatus, near Tampa Bay". Florida Fishery Bulletin 87: 845–857. 
  29. ^ Wintner, S.P. and Cliff, G. (1996). "Age and growth determination of the blacktip shark, Carcharhinus limbatus, from the east coast of South Africa". Fishery Bulletin 94 (1): 135–144. 
  30. ^ Chapman, D.D., Firchau, B. and Shivji, M.S. (2008). "Parthenogenesis in a large-bodied requiem shark, the blacktip Carcharhinus limbatus". Journal of Fish Biology 73: 1473–1477. doi:10.1111/j.1095-8649.2008.02018.x. 
  31. ^ ISAF Statistics on Attacking Species of Shark. International Shark Attack File, Florida Museum of Natural History, University of Florida. Retrieved on April 22, 2009.
  32. ^ "Carcharhinus limbatus". IUCN Red List of Threatened Species. Version 2007. International Union for Conservation of Nature. 2000. 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
Blacktip Shark 2 by Inked Animal
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha
Order: Carcharhiniformes
Family: Carcharhinidae
Genus: Carcharhinus
Species: C. limbatus
Binomial name
Carcharhinus limbatus
(J. P. Müller & Henle, 1839)
Blacktip Shark 2 by Inked Animal
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 1–10 pups every other year. Young blacktip sharks spend the first months of their lives in shallow nurseries, and grown females will 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 International Union for Conservation of Nature (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

Blacktip Shark 2 by Inked Animal
The blacktip shark has black markings on most of its fins.

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 2 symphysial teeth (at the jaw midline) in the upper jaw and 1 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; there is no ridge running 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 (9.0 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

Blacktip Shark 2 by Inked Animal
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 southern China to northern Australia, including 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 (100 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.[10]

Biology and ecology

The blacktip shark is an extremely fast, energetic predator that is usually found in groups of varying size.[3] There is segregation by sex and age; adult males and non-pregnant 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.[11] Predator avoidance may also be the reason why juvenile blacktips do not congregate in the areas of highest prey density in the bay.[12] 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][13][14] This species is also parasitized by nematodes in the family Philometridae, which infest the ovaries.[15]

Behavior

Blacktip Shark 2 by Inked Animal
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 to 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.[16] The speed attained by the shark during these jumps has been estimated to average 6.3 m/s (21 ft/s).[17]

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; it is possible that one of these behaviors is derived from the other.[18]

Feeding

Fish make up some 90% of the blacktip shark's diet.[19] 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).[19] Off South Africa, jacks and herring are the most important prey.[20] Hunting peaks at dawn and dusk.[19] 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 4–7 (range 1–10) 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.[21][22] 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.[21][23]

Mating occurs from spring to early summer, and the young are born at around the same time the following year after a gestation period of 10–12 months.[1] Females have one functional ovary and two functional uteruses; each uterus is separated into compartments with a single embryo inside each.[24] 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.[10] 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.[10][24] The mortality rate in the first 15 months of life is 61–91%, with major threats being predation and starvation.[25] The young remain in the nurseries until their first fall, at which time they migrate to their wintering grounds.[10]

The growth rate of this species slows with age: 25–30 cm (10–12 in) in the first six months, then 20 cm (8 in) a year until the second year, then 10 cm (4 in) a year until maturation, then 5 cm (2 in) a year for adults.[26][27] 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,[10] 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,[26][28] 1.5 m (4.9 ft) and 1.6 m (5.2 ft) respectively off South Africa,[29] and 1.7 m (5.6 ft) and 1.8 m (5.9 ft) respectively off North Africa.[24] The age at maturation is 4–5 years for males and 7–8 years for females.[26][28] The lifespan is at least 12 years.[1]

In 2007, a 9-year-old female blacktip shark at the Virginia Aquarium & 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.[30]

Human interactions

Blacktip Shark 2 by Inked Animal
The blacktip shark usually poses little danger to divers.

There are reports of blacktip sharks showing curiosity towards divers, but remaining at a safe distance. Under most circumstances, this timid shark is 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.[31] 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, South China Sea, and off northern Australia.[27]

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 (IGFA). 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.[27] The International Union for Conservation of Nature (IUCN) has assessed the blacktip shark as Near Threatened, as its low reproductive rate renders it vulnerable to overfishing.[32] 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 (LCS) category of the US National Marine Fisheries Service (NMFS) Atlantic shark Fisheries Management Plan (FMP). No conservation plans specifically for this species have been implemented.[27]

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. and 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. ^ 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. 
  11. ^ Heupel, M.R. and Simpfendorfer, C.A. (2005). "Quantitative analysis of aggregation behavior in juvenile blacktip sharks". Marine Biology 147: 1239–1249. doi:10.1007/s00227-005-0004-7. 
  12. ^ Heupel, M.R. and 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: 543–550. doi:10.1071/MF01132. 
  13. ^ Bullard, S.A., Frasca, A. (Jr.) and 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. 
  14. ^ Bullard, S.A., Benz, G.W. and Braswell, J.S. (2000). "Dionchus postoncomiracidia (Monogenea: Dionchidae) from the skin of blacktip sharks, Carcharhinus limbatus (Carcharhinidae)". Journal of Parasitology (86): 245–250. 
  15. ^ Rosa-Molinar, E. and 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. 
  16. ^ Riner, E.K. and 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. 
  17. ^ 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 1578268. PMID 16849197. 
  18. ^ Ritter, E.K. and Godknecht, A.J. (February 1, 2000). "Agonistic Displays in the Blacktip Shark (Carcharhinus limbatus)". In Ross, S. T. Copeia 2000 (1): 282–284. doi:10.1643/0045-8511(2000)2000[0282:ADITBS]2.0.CO;2. 
  19. ^ 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.
  20. ^ Dudley, S.F.J. and 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. 
  21. ^ a b Keeney, D.B., Heupel, M., Hueter, R.E. and 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: 1039–1046. doi:10.1007/s00227-003-1166-9. 
  22. ^ 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. 
  23. ^ Keeney, D.B., Heupel, M.R., Hueter, R.E. and 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. 
  24. ^ a b c Capapé, C.H., Seck, A.A., Diatta, Y., Reynaud, C.H., Hemida, F. and Zaouali, J. (2004). "Reproductive biology of the blacktip shark, Carcharhinus limbatus (Chondrichthyes: Carcharhinidae) off West and North African Coasts". Cybium 28 (4): 275–284. 
  25. ^ Heupel, M.R. and 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. 
  26. ^ a b c Branstetter, S. (Dec 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. 
  27. ^ a b c d Fowler, S.L., Cavanagh, R.D., Camhi, M., Burgess, G.H., Cailliet, G.M., Fordham, S.V., Simpfendorfer, C.A. and 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. 
  28. ^ a b Killam, K.A. and Parsons, G.R. (May 1989). "Age and Growth of the Blacktip Shark, Carcharhinus limbatus, near Tampa Bay". Florida Fishery Bulletin 87: 845–857. 
  29. ^ Wintner, S.P. and Cliff, G. (1996). "Age and growth determination of the blacktip shark, Carcharhinus limbatus, from the east coast of South Africa". Fishery Bulletin 94 (1): 135–144. 
  30. ^ Chapman, D.D., Firchau, B. and Shivji, M.S. (2008). "Parthenogenesis in a large-bodied requiem shark, the blacktip Carcharhinus limbatus". Journal of Fish Biology 73: 1473–1477. doi:10.1111/j.1095-8649.2008.02018.x. 
  31. ^ ISAF Statistics on Attacking Species of Shark. International Shark Attack File, Florida Museum of Natural History, University of Florida. Retrieved on April 22, 2009.
  32. ^ "Carcharhinus limbatus". IUCN Red List of Threatened Species. Version 2007. International Union for Conservation of Nature. 2000. Retrieved April 27, 2009. 
source: http://en.wikipedia.org/wiki/Blacktip_shark

Blacktip Shark 1

Blacktip Shark 1 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
Blacktip Shark 1 by Inked Animal
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha
Order: Carcharhiniformes
Family: Carcharhinidae
Genus: Carcharhinus
Species: C. limbatus
Binomial name
Carcharhinus limbatus
(J. P. Müller & Henle, 1839)
Blacktip Shark 1 by Inked Animal
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 1–10 pups every other year. Young blacktip sharks spend the first months of their lives in shallow nurseries, and grown females will 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 International Union for Conservation of Nature (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

Blacktip Shark 1 by Inked Animal
The blacktip shark has black markings on most of its fins.

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 2 symphysial teeth (at the jaw midline) in the upper jaw and 1 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; there is no ridge running 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 (9.0 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

Blacktip Shark 1 by Inked Animal
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 southern China to northern Australia, including 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 (100 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.[10]

Biology and ecology

The blacktip shark is an extremely fast, energetic predator that is usually found in groups of varying size.[3] There is segregation by sex and age; adult males and non-pregnant 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.[11] Predator avoidance may also be the reason why juvenile blacktips do not congregate in the areas of highest prey density in the bay.[12] 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][13][14] This species is also parasitized by nematodes in the family Philometridae, which infest the ovaries.[15]

Behavior

Blacktip Shark 1 by Inked Animal
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 to 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.[16] The speed attained by the shark during these jumps has been estimated to average 6.3 m/s (21 ft/s).[17]

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; it is possible that one of these behaviors is derived from the other.[18]

Feeding

Fish make up some 90% of the blacktip shark's diet.[19] 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).[19] Off South Africa, jacks and herring are the most important prey.[20] Hunting peaks at dawn and dusk.[19] 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 4–7 (range 1–10) 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.[21][22] 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.[21][23]

Mating occurs from spring to early summer, and the young are born at around the same time the following year after a gestation period of 10–12 months.[1] Females have one functional ovary and two functional uteruses; each uterus is separated into compartments with a single embryo inside each.[24] 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.[10] 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.[10][24] The mortality rate in the first 15 months of life is 61–91%, with major threats being predation and starvation.[25] The young remain in the nurseries until their first fall, at which time they migrate to their wintering grounds.[10]

The growth rate of this species slows with age: 25–30 cm (10–12 in) in the first six months, then 20 cm (8 in) a year until the second year, then 10 cm (4 in) a year until maturation, then 5 cm (2 in) a year for adults.[26][27] 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,[10] 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,[26][28] 1.5 m (4.9 ft) and 1.6 m (5.2 ft) respectively off South Africa,[29] and 1.7 m (5.6 ft) and 1.8 m (5.9 ft) respectively off North Africa.[24] The age at maturation is 4–5 years for males and 7–8 years for females.[26][28] The lifespan is at least 12 years.[1]

In 2007, a 9-year-old female blacktip shark at the Virginia Aquarium & 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.[30]

Human interactions

Blacktip Shark 1 by Inked Animal
The blacktip shark usually poses little danger to divers.

There are reports of blacktip sharks showing curiosity towards divers, but remaining at a safe distance. Under most circumstances, this timid shark is 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.[31] 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, South China Sea, and off northern Australia.[27]

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 (IGFA). 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.[27] The International Union for Conservation of Nature (IUCN) has assessed the blacktip shark as Near Threatened, as its low reproductive rate renders it vulnerable to overfishing.[32] 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 (LCS) category of the US National Marine Fisheries Service (NMFS) Atlantic shark Fisheries Management Plan (FMP). No conservation plans specifically for this species have been implemented.[27]

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. and 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. ^ 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. 
  11. ^ Heupel, M.R. and Simpfendorfer, C.A. (2005). "Quantitative analysis of aggregation behavior in juvenile blacktip sharks". Marine Biology 147: 1239–1249. doi:10.1007/s00227-005-0004-7. 
  12. ^ Heupel, M.R. and 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: 543–550. doi:10.1071/MF01132. 
  13. ^ Bullard, S.A., Frasca, A. (Jr.) and 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. 
  14. ^ Bullard, S.A., Benz, G.W. and Braswell, J.S. (2000). "Dionchus postoncomiracidia (Monogenea: Dionchidae) from the skin of blacktip sharks, Carcharhinus limbatus (Carcharhinidae)". Journal of Parasitology (86): 245–250. 
  15. ^ Rosa-Molinar, E. and 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. 
  16. ^ Riner, E.K. and 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. 
  17. ^ 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 1578268. PMID 16849197. 
  18. ^ Ritter, E.K. and Godknecht, A.J. (February 1, 2000). "Agonistic Displays in the Blacktip Shark (Carcharhinus limbatus)". In Ross, S. T. Copeia 2000 (1): 282–284. doi:10.1643/0045-8511(2000)2000[0282:ADITBS]2.0.CO;2. 
  19. ^ 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.
  20. ^ Dudley, S.F.J. and 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. 
  21. ^ a b Keeney, D.B., Heupel, M., Hueter, R.E. and 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: 1039–1046. doi:10.1007/s00227-003-1166-9. 
  22. ^ 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. 
  23. ^ Keeney, D.B., Heupel, M.R., Hueter, R.E. and 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. 
  24. ^ a b c Capapé, C.H., Seck, A.A., Diatta, Y., Reynaud, C.H., Hemida, F. and Zaouali, J. (2004). "Reproductive biology of the blacktip shark, Carcharhinus limbatus (Chondrichthyes: Carcharhinidae) off West and North African Coasts". Cybium 28 (4): 275–284. 
  25. ^ Heupel, M.R. and 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. 
  26. ^ a b c Branstetter, S. (Dec 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. 
  27. ^ a b c d Fowler, S.L., Cavanagh, R.D., Camhi, M., Burgess, G.H., Cailliet, G.M., Fordham, S.V., Simpfendorfer, C.A. and 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. 
  28. ^ a b Killam, K.A. and Parsons, G.R. (May 1989). "Age and Growth of the Blacktip Shark, Carcharhinus limbatus, near Tampa Bay". Florida Fishery Bulletin 87: 845–857. 
  29. ^ Wintner, S.P. and Cliff, G. (1996). "Age and growth determination of the blacktip shark, Carcharhinus limbatus, from the east coast of South Africa". Fishery Bulletin 94 (1): 135–144. 
  30. ^ Chapman, D.D., Firchau, B. and Shivji, M.S. (2008). "Parthenogenesis in a large-bodied requiem shark, the blacktip Carcharhinus limbatus". Journal of Fish Biology 73: 1473–1477. doi:10.1111/j.1095-8649.2008.02018.x. 
  31. ^ ISAF Statistics on Attacking Species of Shark. International Shark Attack File, Florida Museum of Natural History, University of Florida. Retrieved on April 22, 2009.
  32. ^ "Carcharhinus limbatus". IUCN Red List of Threatened Species. Version 2007. International Union for Conservation of Nature. 2000. 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
Gafftopsail Catfish 2 by Inked Animal
Conservation status
Not evaluated (IUCN 3.1)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Ariidae
Genus: Bagre
Species: B. marinus
Binomial name
Bagre marinus
(Mitchill, 1815)

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. They are 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 also lives on the coastlines from Cape Cod to Venezuela. It is found in brackish waters, including estuaries, lagoons, brackish seas, and also mangroves.

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.[1] 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).[2] 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;[3] 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.[4]

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 poisonous spines; care should be used when handling this fish.

Weight and length

Gafftopsail Catfish 2 by Inked Animal
Growth chart

The largest recorded weight for a a

gafftopsail catfish is 4.5 kg (10 lb).[5] A more common weight and length of gafftopsails caught is 1-2 lb and 12-16 inches.

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:

Gafftopsail Catfish 2 by Inked Animal

Invariably, b is close to 3.0 for all species, and the constant ct varies between species.[6] Data from the Florida Fish and Wildlife Conservation Commission indicate, for the gafftopsail catfish, c = 0.000493 and b = 3.075[7] 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. ^ 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
  2. ^ FishBase.org: Food and Feeding Habits Summary - Bagre Marinus see online accessed 11 March 2010
  3. ^ 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
  4. ^ Smith, pp. 85 & 346
  5. ^ 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
  6. ^ 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.
  7. ^ average of data for male and female gafftopsail catfish at Florida Fish and Wildlife Conservation Commission Report 2008 accessed 7 March 2010

External links

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

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