Carcharhiniformes Triakidae (the houndsharks) Jeff Guertin 10/30/07 9 Genera, ~39 species




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Carcharhiniformes Triakidae (the houndsharks)

Jeff Guertin



10/30/07
9 Genera, ~39 species

  • Furgaleus (whiskery shark) - one species

  • Galeorhinus (school shark, oil shark, vitamin shark) - one species

  • Gogolia (sailback houndshark) - one species

  • Hemitriakis (whitefin tope sharks) - four species (plus 2 unnamed)

  • Hypogaleus (japanese tope shark) - one species

  • Iago (bigeye houndsharks) - two species

  • Mustelus (smooth hound sharks, smooth dogfishes, gummy sharks) ~22 species (plus 2 unnamed)

  • Scylliogaleus (flapnose houndshark) - one species

  • Triakis (leopard sharks) - 5 species


General Characteristics

  • Small to moderate-sized sharks

  • Some of the most abundant sharks off of Atlantic and Pacific coasts of North America

  • Horizontally oval eyes

  • Nictitating eyelids

  • Anterior nasal flaps


Distinctive Features

  • Small rounded teeth

  • Three to four separate cusps

  • First dorsal in front of the pelvic

  • No precaudal pits

  • Caudal fin may or may not have a strong ventral lobe

  • Two large-sized, spineless dorsal fins

  • Anal fin

  • T. semifasciata - distinctive markings provide camouflage against dappled ground; well developed spiracle; sometimes tinged with iridescence

  • M. canis - melanophores; spiracle is only of moderate size; pronounced sub-ocular fold

  • G. galeus - pronounced spiracles; first dorsal much larger than second dorsal


Habitat

  • Tropical and temperate seas worldwide

  • Mostly occur on continental and insular shelves

  • a few are deepwater slope dwellers (up to 2000m)

  • None are oceanic

  • Some seasonally migrate

  • Leopard Shark (Triakis semifasciata) - Eastern Pacific (Mexico to Oregon) but mostly in San Francisco Bay

  • Smooth dogfish (Mustelus canis) - Western Atlantic (Cape Cod to Uruguay)

  • Tope shark (Galeorhinus galeus) - Eastern Atlantic (largest inshore native shark in British waters); Oceania, South Africa, South America


Food Habits

  • Feed primarily on bottom and mid-water invertebrates and bony fishes

  • Worms, mollusks, crustaceans, octopuses

  • T. semifasciata - hunt in groups, sometimes with smooth-hound sharks

Size, Age, & Growth

  • T. semifasciata - born at a length of about 20 cm, max length of 180cm-200cm (avg. 150cm); maximum reported age about 50yrs

  • M. canis - max size roughly 150cm (avg. 122cm); males have a life span of 10yrs, females 16yrs; males mature 2-3yrs and females mature 3-4yrs

  • G. Galeus - max size roughly 190cm for males, 195cm for female; mature ~10-15yrs; life span up to 55 years


Reproduction

  • Live bearing (both viviparous and ovoviviparous)

  • Litters range from 1-52

  • T. semifasciata - migrate seasonally; aplacental viviparity (ovoviviparous); 4 to 33 pups per litter; Gestation is estimated at 10 to 12 months.

  • M. Canis - viviparous; 4-20 embryos of varying ages, not all born at once; ~10 month gestation

  • G. Galeus - aplacental viviparity; produce young every 2 yrs; 6-52 pups/litter


Predators

  • Marine mammals

  • Other large fish (Carcharodon carcharias in particular for leopard sharks)

  • Sharpnose Sevengill (Heptranchias perlo) is a primary predator of tope sharks


Conservation

  • T. semifasciata - Lower Risk according to IUCN; but actively sought by sport fishermen in the San Francisco Bay Area and in Monterey Bay for food

  • M. canis - Near Threatened according to IUCN; sought by small fisheries but mostly by-catch; often used as lab specimen and in aquaria

  • G. galeus - Vulnerable globally and Near Threatened in New Zealand according to IUCN; commercially harvested


Bibliography

  • Carrier, J,, Musick, J., and Heithaus, M. 2004. Biology of Sharks and Their Relatives. CRC Press, Boca Raton.

  • Cailliet, GM (1992). Demography of the central california population of the Leopard Shark (Triakis semifasciata). Australian Journal of Marine and Freshwater Research 43, 183–193.

  • Conrath CL and Musick JA. 2002. Reproductive Biology of the Smooth Dogfish, Mustelus canis, in the Northwest Atlantic Ocean. Environmental Biology of Fishes 64, 367-377.

  • Florida Museum of National History. <http://www.flmnh.ufl.edu/fish/>. Downloaded on 25 October 2007.

  • IUCN 2006. 2006 IUCN Red List of Threatened Species. . Downloaded on 25 October 2007.

  • Nelson, J. 1984. Fishes of the World. 2nd Ed. John Wiley & Sons, Inc., New York.

  • Parker, S. 1999. The Encyclopedia of Sharks. Firefly Books, Buffalo.

  • Perrine, D. 1999. Sharks and Rays of the World. Voyageur Press, Hong Kong.

  • Steel, R. 1985. Sharks of the World. Facts on File, Inc., New York.


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