Transcript Orectolobiformes Rhincodontidae

Carcharhiniformes Triakidae
(the hound sharks)
Jeff Guertin
10/30/07
9 Genera, ~39 species
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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
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Small to moderate-sized sharks
Benthopelagic
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
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Small rounded teeth
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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
Distinctive Features
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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
Distinctive Features
Smooth Dogfish
Leopard Shark
Tope Shark
Habitat
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Tropical and temperate seas worldwide
Mostly occur on continental and insular
shelves
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a few are deepwater slope dwellers (up to 2000m)
None are oceanic
Some seasonally migrate
Habitat
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Leopard Shark (Triakis
semifasciata) - Eastern
Pacific (Mexico to Oregon)
but mostly in San
Francisco Bay
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Smooth dogfish (Mustelus
canis) - Western Atlantic
(Cape Cod to Uruguay)
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Tope shark (Galeorhinus
galeus) - Eastern Atlantic
(largest inshore native
shark in British waters);
Oceania, South Africa,
South America
Food Habits
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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
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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
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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
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Marine mammals
Other large fish (Carcharodon carcharias in
particular for leopard sharks)
Sharpnose Sevengill (Heptranchias perlo) is a
primary predator of tope sharks
Conservation
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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
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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.
<http://www.iucnredlist.org>. 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.