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Carcharhinidae
Requiem sharks
Carcharhinidae characteristics
5 gill slits 2 dorsal fins
No fin spines Caudal fin w/ strong ventral lobe Mouth behind eyes Round eyes w/ nictitating eyelids Long arched mouth w/ bladelike teeth Short labial furrows Mostly unpatterned
Characteristic cont.
Mostly medium to large 100-300 cm
Some smaller ~100
Active strong swimmers More nocturnal
Some dusk and dawn Ram ventilators & buccal pumpers
Behavior
Some solitary Some socialize in small groups Some social schooling spp. Some segregate by size, sex and/or age Clear hierarchical dominance b/t spp.
Oceanic whitetip (Carcharhinus longimanus) dominate silky sharks
Silky sharks (Carcharhinus falciformis) dominate grey reef sharks (Carcharhinus amblyrhynchos)
Taxonomy
Order Carcharhiniformes Family carcharhinidae
12 genera (8 monotypic) ~50 spp. (31 are in genus Carcharhinus)
Examples include Tiger shark (Galeocerdo cuvier) Bull shark (Carcharhinus leucas) Blacktip reef (Carcharhinus melanopterus) Sharpnose sharks (Rhizopriondon spp.) Lemon Shark (Negaprion brevirostris)
Distribution
Temperate and tropical seas Majority tropical continental shelves & offshore Some coral reefs Some deep water Benthopelagic Pelagic-Blue Shark (Prionace glauca), Oceanic
Whitetip (Carcharhinus longimanus), Silky Shark (Carcharhinus falciformis)
All over the world
Worldwide distribution
Feeding
Wide variety Teleosts Crustaceans Mollusks Elasmobranchs Seabirds Reptiles Marine mammals
Reproduction
Most placental viviparous Galeocerdo cuvier is ovoviviparous
(aplacental viviparity) Biennial or triennial reproductive
cycle
Tiger shark different than other Carcharinidaes
Carcharinidae
Tiger shark
Status
Important in commercial, subsistence and sports fisheries
used for Food Liver oil Fins-especially blue shark Skin
Ecotourism Have bitten people Caught as bycatch Red list mixed from data deficient; threatened to
endangered; many near threatened
Tiger shark (Galeocerdo cuvier)
Tiger shark (Galeocerdo cuvier)
Bull shark (Carcharhinus leucas)
Dusky (Carcharhinus obscurus)
Dusky shark Carcharhinus obscurus
Lemon shark (Negaprion brevirostris)
Whitecheek shark jaw(Carcharhinus dussumieri)
Oceanic Whitetip shark (Carcharhinus longimanus)
Blue shark (Prionace glauca)
Blue Shark (Prionace glauca)
Silky shark (Carcharhinus falciformis)
Silky shark (Carcharhinus falciformis) jaw
Shark finning
Annually 100 million sharks killed 2% of shark body is fins 32 tons =30,000 sharks $32-328 per pound of shark fin Sold for ~$100 a bowl Thought to increase vital energy, nourish
blood, improve kidney and lung function Actually potential for mercury poisoning
New laws
NOAA banned shark finning in 2004 in Atlantic
NMFS enacted Shark finning Prohibition Act in 2000
China is main consumer
Shark finning
How sad!
“shark fin, get your shark fin”
Shark's Fin Soup Serves 6 4 dried black mushrooms 2 scallion stalks Fresh ginger root 16-oz shark's fin (the shinier the better) 2 tbsp sherry 4 cup water 1 chicken breast 2 scallion stalks 3 tbsp oil 5 cup stock 1 tsp salt 2 tbsp sherry 2 tbsp cornstarch 1 cup Stock Soak dried mushrooms. Trim scallion stalks; slice ginger root and
combine in a pan with canned shark's fin, sherry and water. Bring to a boil, then simmer, covered, 15 minutes. Drain shark's fin, discarding liquid, scallions and ginger root. Meanwhile skin, bone and shred chicken breast. Shred soaked mushrooms; cut remaining scallions in 2-inch sections. Heat oil. Brown scallion sections lightly and discard. Add chicken shreds and stir-fry until they lose their pinkness (about 1 minute). Add stock, salt, shark's fin, mushrooms, and remaining sherry. Bring to a boil; then simmer, covered, 30 minutes. Blend cornstarch and remaining cold stock; then stir in to thicken soup, and serve, enjoy.
Literature cited
Compagno, L.M. Dando, and S. Fowler. 2005. Sharks of the world.Princeton University Press, Princeton, NJ. Pp288-322
Whitney NM, Crow GL. 2007. Reproductive biology of the tiger shark (Galeocerdo cuvier) in Hawaii. Marine Biology. 151 (1).pp63-70
Yokota K, Kiyota M, Minami H.2006.Shark catch in a pelagic longline fishery: Comparison of circle and tuna hooks. Fisheriess Research. 81.pp 337-341.
Clarke SC, McAllister MK, Milner-Gulland EJ, et al.2006.Global estimates of shark catches using trade records from commercial markets .Ecology Letter 9.pp 1115-1126
Literature cited
Campana SE, Marks L, Joyce W, et al.Effects of recreational and commercial fishing on blue sharks(Prionace glauca) in Atlantiv Canada, with inferences on the North Atlantic population. 2006. CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES 63 .pp 670-682
IUNC 2006. 2006 IUCN red list of threatned species. At http://www.iuncnredlist.org
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