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Biological Profiles

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South Florida Aquatic Environments About the Different Groups of Fishes About the Anatomy of Fish and Sharks How Fish and Sharks Swim About Fish Adaptations About the Endangered Species Act How to Become a Biologist About Careers In Ichthyology Most Commonly Asked Shark Questions Most Commonly Asked Sawfish Questions Most Commonly Asked Ray and Skate Questions Most Commonly Asked Fish Questions Identification Key to Freshwater Fishes of Peninsular Florida Field Key to Sharks Skates of the Western Gulf of Maine Project Shark Awareness - A Public Outreach Educational Program Shark Fishing in U.S. Territorial Waters Most Commonly Asked Sawfish Questions Sawfish In Peril - PowerPoint file Sawfish Informational Brochure - Acrobat file Sawfish Outreach Boat Ramp/Marina Sign - Acrobat file Sawfish References Sawfish Links Smalltooth Sawfish species profile Largetooth Sawfish species profile Green Sawfish species profile Freshwater Sawfish species profile Dwarf Sawfish species profile Knifetooth Sawfish species profile Chondrichthyes Bibliography Search Freshwater Fishes of Florida References General Fish References Shark References Sawfish References Childrens' Shark Books Stingray Reproduction References Biological Profiles Glossary of Terms Shark Games: Test Your Knowlege! 2003 Open House Photos TIGER SHARK Order - Carcharhiniformes Family - Carcharhinidae Genus - Galeocerdo Species - cuvier Taxonomy First described by Peron and Lessueur in Lessueur (1822), the tiger shark was given the name Squalus cuvier. Later, Muller and Henle (1837) designated Squalus arcticus (Faber, 1829) as the type species and suggested the name Galeocerdo tigrinus. Various synonyms have been used since including: Galeus cepedianus Agassiz 1838, Galeus maculatus Ranzani 1840, Carcharias fasciatus Bleeker 1852, Galeocerdo rayneri McDonald & Barron 1868, Galeocerdo obtusus Klunzinger 1871, and Carcharias hemprichii Klunzinger 1871. The genus name Galeocerdo is derived from the ancient Greek, "γαλεος" (galeos) = Aristotle's shark and "κερδω" (kerdo) = the fox. Common Names Tiger shark, leopard shark, maneater shark, and spotted shark are English language common names that refer to this shark. Other names include alecrin (Spanish), amarillo (Spanish), amzani (Swahili), bhoavar (Gujarati), cabron (Spanish), cação cabeça-chata (Portuguese), carcharias (Greek), cucut macan (Malay), itachizame (Japanese), jaguara (Portuguese), jarjur (Arabic), jarjur knaza (Arabic), kethulam (Telugu), ma`o patapata (Rapa), mangeur d'hommes (French), mano pa'ele (Hawaiian), ma'o tore tore (Tahitian), marracho tigre (Portuguese), naiufi (Samoan), ngutukao (Maori), pating (Tagalog), pilithatte (Kannada), pulli sravu (Malayalam), qio saga (Fijian), requin demoiselle (French), requin tigre (Creole), requin tigre commun (French), requin-demoiselle (French), requin-tigre (French), squalo tigre (Italian), te babatababa (Kiribati), tiburón tigre (Spanish), tierhaai (Afrikaans), tigerhai (German), tigre (Portuguese), tígrisháfur (Icelandic), tiikerihai (Finnish), tijgerhaai (Dutch), tintorera (Spanish), tintureira (Portuguese), wulluven sorrah (Tamil), and zarlacz tygrysi (Polish). Geographical Distribution The tiger shark is found throughout the world's temperate and tropical waters, with the exception of the Mediterranean Sea. It is a wide-ranging species that is at home both in the open ocean as well as shallow coastal waters. Reports of individuals from as far north as Iceland and the United Kingdom have been confirmed but are probably a result of roaming sharks following the warmer Gulf Stream north across the Atlantic. World distribution map for the tiger shark Habitat This shark has a notable tolerance for many different kinds of marine habitat but generally prefers murky waters in coastal areas. It is commonly found in river estuaries, harbors, and other inlets where runoff from the land may attract a high number of prey items. Shallow areas around large island chains and oceanic islands including lagoons, are also part of the tiger shark's natural environment. It is often seen at the surface and has been reported to depths of 350 m (1085 ft). Tiger sharks undergo seasonal migrations. It is well known that they move into temperate waters from the tropics for the warmer months and return during the winter. These sharks also make long oceanic migrations between islands and are capable of traveling long distances in a short amount of time. Biology Tiger Shark © John Soward · Distinctive Features Probably the most easy to recognize of the requiem sharks, the tiger gets its name from dark black spots and vertical bars which run the length of the body. The anterior portion of the body is stout but becomes increasingly slender posterior to the abdomen. The tiger shark has a robust head with large eyes and a very blunt snout. The mouth itself is large with long labial furrows. The broad first dorsal fin originates posterior to the pectoral axil. The much smaller second dorsal fin initiates anterior to the origin of the strongly recurved anal fin. A ridge is present along the back between the dorsal fins. A low longitudinal keel is present on the caudal peduncle and the upper lobe of the caudal fin is long and thin with a subterminal notch. Anatomy of the tiger shark ex Casey (1964) Bur. Sport Fish. & Wildl. Circ., 179 · Coloration Bluish-green to dark gray or black dorsal surface with a yellowish-white to stark white underbelly. The characteristic dark spots and stripes are most prominent in young sharks and fade as the shark matures. Juvenile Tiger shark showing color pattern © George Burgess · Dentition The tiger shark has very distinct dentition. The jaws house large teeth with curved cusps and finely serrated edges. Each tooth has a deep notch on the outer margin lined with numerous cusplets. Upper and lower teeth are similar in shape and size and decrease in measurement as they move back toward the mouth's corners. · Size, Age, and Growth One of the largest sharks, the tiger shark commonly reaches a length of 325-425 cm (10-14 ft) and weighs over 385-635 kg (850-1400 lbs). Length at birth varies from 51-76 cm (1-1.5 ft). Males reach sexual maturity at 226-290 cm (7-9 ft), while females become mature at 250-325 cm (8-10 ft). The largest specimens are believed to attain a length of over 5.5 m (17 ft) and weigh over 900 kg (2000 lbs). A) Upper and lower teeth of Galeocerdo cuvier, ex Casey (1964) Bur. Sport Fish. & Wildl Circ. 179, and B) Juvenile tiger shark showing dentition © George Burgess · Food Habits Tiger sharks feed on the green sea turtle courtesy NOAA Undoubtedly the least discriminative all species, the tiger shark has a reputation as an animal that will eat almost anything. Preferred prey varies depending upon geographical region but commonly includes sea turtles, rays, other sharks, bony fishes, sea birds, dolphins, squid, various crustaceans and carrion. The tiger shark's highly serrated teeth combined with the saw-like action from shaking the head back and forth allows it to tear chunks from much larger marine animals. Interestingly, it is not uncommon to find objects of human origin in this animal's stomach. One large female caught off the north end of the Gulf of Aqaba in the Red Sea contained two empty cans, a plastic bottle, two burlap sacks, a squid, and a 20 cm (8 in) fish. Garbage and refuse is often recovered from the stomachs of sharks caught in harbors and river inlets where it is commonly dumped into the water. Although far from a natural food item, human remains sometime end up in the guts of these scavenging sharks. Tiger sharks are solitary hunters that feed primarily at night as the shark moves further inshore and closer to the surface. Tiger sharks are sometimes seen in groups of several but this is probably a result of congregations of food items in the vicinity. · Reproduction Female tiger shark with mating scars from bites of male during mating attempts © Doug Perrine The tiger shark is the only species of its family that is ovoviviparous. The gestation period ranges from 14-16 months, at which time a female can give birth to anywhere from 10 to 80 pups. In the Northern Hemisphere, mating takes place between March and May and the young are born between April and June of the following year. In the Southern Hemisphere, it is believed that pupping occurs in November to January. It is believed by some scientists that because of the large size of the young at birth, uterine nutrition is supplemented by 'uterine milk' secreted by the lining of the uterus. Newborn tiger shark © Doug Perrine Importance to Humans Tiger shark caught during a fishing derby off Jacksonville, Florida in 1981 © FLMNH Although not targeted directly by the commercial fishery in the US, the tiger shark is routinely harvested for its fins and flesh. In addition, its liver, which tends to have a very high vitamin A content, is used to produce vitamin oil while its thick, tough skin makes for quality leather. Beside its significance to the commercial fishery, the tiger shark is a highly sought after big game fish. Danger to Humans The tiger shark is second only to the white shark in number of reported attacks on humans. Its large size and voraciousness make it a formidable predator in the ocean. Tiger sharks can be curious and aggressive towards humans in the water and must be considered with a great deal of respect. Conservation Both commercial and recreational fishing catch rates for this species in the mid-Atlantic region have declined since the mid-1980's, indicating that fishing pressure has adversely affected the size of the population. In contrast, relative abundance and catch rates for this species noted by commercial fisheries observers, especially for juveniles, are much higher than in previous fishery-independent and fishery-dependent surveys. The World Conservation Union (IUCN) presently lists the tiger shark as "Near Threatened" throughout its range. The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species. Prepared by: Craig Knickle