Author: (Linnaeus, 1758)
Field Marks:
Heavy spindle-shaped body, moderately long conical snout, huge, flat, triangular, serrated bladelike teeth, long gill slits, large first dorsal fin without light free rear tip, minute, pivoting second dorsal and anal fins, strong keels on caudal peduncle, no secondary keels on caudal base, crescentic caudal fin, ventral surface on body white.
Diagnostic Features:
Body usually stout. Snout bluntly conical, rather short; nostrils lateral on snout, situated adjacent to head rim in ventral view; mouth broadly parabolic; teeth flat, tirangular, with broad, serrated, nearly straight cusps, and lateral cusplets only in juveniles below 2 m long (which may have at least some smooth-edged or partially smooth); intermediate teeth in upper jaw very large, over half height of upper anteriors. First dorsal origin usually over the pectoral inner margins; anal origin under or slightly posterior to second dorsal insertion; no secondary keels on base of caudal.
Geographical Distribution:
Coastal and mostly amphitemperate. Western Atlantic: Newfoundland to Florida, Bahamas, Cuba, northern Gulf of Mexico; Brazil and Argentina. Eastern Atlantic: France to Mediterranean, Madeira, Canary Islands, Senegal, Ghana, Zaire; Western Cape Province, South Africa. Western Indian Ocean: South Africa, Scychelles Islands, Red Sea. Western Pacific: Siberia (USSR), Japan, the Koreas, China, Bonin Island, the Philippines; ?Indonesia, Australia (Queensland, New South Wales, Victoria, Tasmania, South and Western Australia), New Zealand, New Caledonia. Central Pacific: Marshall Islands, Hawaiian Islands. Eastern Pacific: Gulf of Alaska to Gulf of Carlifornia: Panama to Chile.
Habitat and Biology:
This huge, fearsome shark is primarily a coastal and offshore inhabitant of the continental and insular shelves. The occurrence of large individuals off oceanic islands far from land where breeding populations of the species apparently do not exist suggests that it can and does make occasional epipelagic excursions into the ocean basins, even though it has never been taken in longline catches there (unlike its relatives in the genera Isurus and Lamna). The great white shark often occurs close inshore to the surfline and even penetrates shallow bays in continental coastal waters, but also prefers offshore continental islands (especially those with pinniped colonies). The white shark can be found at the surface down to the bottom in epicontlthental waters but occasionally ranges down the continental slope, where it was once caught on a bottom longline at 1280 m along with the large sixgill shark (Hexanchus qriseus).
This species is a very active shark with a stiff, powerful, scombroid-like mode of swimming that allows it to efficiently cruise for long periods at relatively slow speed. A recent offshore tracking attempt on a large shark with sonic tags indicated that it moved 190 km in 2.5 days at an average cruising speed of 3.2 kph. The white shark is capable of sudden high speed dashes and sometimes jumps right out of the water.
Records of the great white shark are commonest from cold and warm temperate areas, though there are enough tropical continental and oceanic records to suggest that at least larger individuals have a wide temperature range and penetrate at will into the tropical stronghold of carcharhinid sharks. Smaller individuals, below 3 m long, may be restricted to temperate seas, and the occurrence of presumably newborn individuals in the 120 to 130 cm size range suggest the pupping grounds for the species are also in temperate waters.
Relatively little is known of the abundance of this species, except that it is relatively uncommon compared to most other sharks where it lives. Catches in some areas may be as many as 47 per year (Natal, South Africa), but mostly less in others. Unfounded claims have been made that the species is increasing in numbers in some areas (off central California, for example), as a result of increasing numbers of pinnipeds, but there is no evidence to prove this, and increasing fishing pressure in such areas may be very well having the reverse effect.
Pronounced periodicity in white shark abundance may occur in some areas, apparently correlated with temperature and to some extent with life stage. In colder, higher latitudes at the periphery of its range- in North America, the white shark moves into more northern areas when water masses warm up in the summertime; conversely, off Natal, South Africa, smaller individuals below 2.8 m long move in the area with a drop in water temperature below 22°C, and apparently depart for colder Cape Coast waters when temperatures rise above this letel; however, larger individuals above 2.8 m seem to occur there all year round. In central California (lflonterey Bay) white sharks are present year round but are slightly commoner when water temperatures rise to 14 or 15°C from below 11°C.
The white shark often occurs singly or in pairs but can be found at food sources in feeding aggregations of 10 or more; schooling apparently does not occur. Behaviour of this species is poorly known, but there is anecdotal evidence to suggest that recognizable individuals may seasonally revisit a favoured site for several years. Territoriality in the white shark cannot be demonstrated at present, but there is some evidence for sorting of individuals into a size-related hierarchy around food sources such as dead whales, pinniped colonies or feeding stations provided by people. Tooth scratches on individuals, including immature females and males, have been interpreted as evidence of intraspecific conflict, possibly in competition for food resources. In certain areas (southern Australia and central California), white sharks may have habituated to human-provided food sources such as fishing boats and feeding stations (to lure white sharks in for photography and profits), and may have learned to come to these places to the delight or dispair of the humans involved (the latter if the sharks steal fish from lines).
Presumably the white shark is ovoviviparous and practices uterine cannibalism as do other lamnoids, but this is uncertain because pregnant females of this species are almost never reported. A litter of 9 young was reported from a Mediterranean female, unfortunately without further details. The rarity of pregnant females may be explained by spatial separation from other white sharks during pregnancy; their sheer size that precludes capture by most fishing gear; and by possibly very low fecundity, with relatively few adult females being pregnant at any one time.
The great white shark is a true superpredator and perhaps the most formidable of fishlike vertebrates. The combination of large size, very powerful jaws and teeth, and a relatively efficient locomotion and metabolism allows it to be a versatile predator with a broad prey spectrum. It also readily scavenges on available carrion, garbage, and secondary kills of fish caught on lines. Prey of the white shark includes a wide range of bony fishes, such as sturgeon, menhaden and pilchards, salmon, hake, halibut, rockfish, cabezon, lingcod, croakers, mackerels and tunas. Chondrichthyian prey includes other sharks such as houndsharks (Galeorhinus, Mustelus), requiem sharks (Carcharhinus, Rhizoprionodon), hammerheads (Sphyrna), and spiny dogfish (Squalus); also stingrays, eagle rays (Myliobatis), and chimaeras. Basking shark (Cetorhinus) meat has been found in several white sharks, apparently taken as carrion from harpooned sharks; it is presently unknown if the white shark ever attacks free-swimming basking sharks. Sea turtles are occasionally taken by the white shark, but apparently not to the degree that the tiger shark (Galeocerdo) preys on them. Birds are uncommonly taken by white sharks and include gannets, gulls, and penguins, but it is uncertain if these items were taken alive. Marine mammals are an important food source for large white sharks, and those killed and eaten include harbour porpoises, dolphins, and a number of pinnipeds such as harbour seals, northern elephant seals, Steller's and California sea lions, South African fur seals, and probably several other species. Sea otters are commonly killed by white sharks off California, but have yet to be found as stomach contents. Dead baleen whales and other large cetaceans may contribute a significant amount to the white shark's diet in some areas; mammalian carrion from slaughterhouses and other sources, including mutton, pig, horse, dog, and rarely human, has been found in the white shark's stomach also. Invertebrate prey includes squids, abalones and other gastropods, and crabs. Inedible garbage is occasionally taken from the stomachs of white sharks, but apparently this species is not fond of swallowing oddities like the tiger shark. Larger white sharks above 3 m long tend to prey heavily on marine mammals, while smaller sharks below 2 m long feed heavily on bony fishes and small sharks, but even large sharks are capable of eating smaller prey such as the 150 crabs, salmons, hakes, and rockfishes found in a 4.4 m specimen from Washington State, USA. Pinnipeds may be especially important prey for white sharks where they occur together, but in tropical areas without these mammals the white shark is probably capable of subsisting on other sharks, bony fishes, turtles and cetaceans.
The great white shark is feared by many people as the most dangerous living shark; more attacks on swimmers, divers, surfers, and boats have been reported for this shark than for any others. It must be remembered, however, that some 80% of the reported shark attacks have occurred in the tropics, where white sharks are rare but where large, dangerous carcharhinid sharks predominate. Tropical carcharhinids, with some exceptions, are difficult to identify in the water, and the ratio of positive identifications of species of these sharks involved in attacks to numbers of tropical shark attacks is very low. In contrast, white sharks are readily identified as the species involved in temperate water shark attacks, probably in part because of the distinctive features of this shark, because of high popular interest in shark attack and the white shark in areas where the attacks occur, and because the white shark may be the only shark that regularly attacks people in these areas (in the tropics, several dangerous species of carcharhinids may occur in a given area). Therefore there might very well be tropical carcharhinids, particularly the tiger and bull sharks, that may be equally dangerous or more dangerous than the white shark, but this remains to be seen.
Although much has been made of white shark attacks in the popular newsmedia, the attack rate is very low, far less than drownings, diving accident, automobile accidents, lightning strokes, or other calamities that afflict humans in the countries where white shark attacks occur. Most white shark attacks have occurred off California (USA), southern Australia, New Zealand, and South Africa. Off north-central California, where the highest rate of white shark attacks is currently known, approximately 41 attacks attributable to these sharks occurred in the 32 year period from 1950 to 1982, averaging 1.3 per year and at a slightly higher rate (about 1.9 per year) at the end of the period than the beginning (about 0.7 per year). Only 4 of these attacks were fatal (0.13 per year); the rest resulted in minor or serious injuries to the people involved. Much speculation has occurred on the behaviour of white sharks in such attacks. The white shark is clearly capable of inflicting mortal wounds with a single bite, but often merely clamps onto its human victims without completing its bite and releases them after a short time. Such behaviour has been interpreted as non-feeding aggression toward people, but also as 'mistaken identity' feeding attacks, in which the shark bites its victim after mistaking it for a seal or other normal prey and then aborts its attack. Another possibility is that such attacks are exploratory 'sampling' of a potential food item, with subsequent rejection. Displacement behaviour and even 'play' are other hypotheses that could be evoked. Fullfledged feeding attacks in which the white shark repeatedly bites and dismembers its human victim have been reported, but fortunately these are extremely rare compared to abortive attacks (the various "JAWS" movies not withstanding).
In recent years several surfers and paddleboarders have been attacked by white sharks, which have sometimes destroyed their boards. Boats may be attacked, particularly if a feeding stimulus like fish catches is involved. For some reason False Bay, South Africa, is the site of more boat attacks by white sharks than all other places combined. White sharks have on a few occasions persistantly attacked boats until they sank, and in at least one instance lept into a boat.
Despite the frightful reputation of the great white shark there is accumulating evidence that, especially for SCUBA divers, the presence of a white shark near people does not necessarily mean that an attack is inevitable. Increasing numbers of cases have been reported where these sharks swim up to divers as close as a few feet and depart without attacking. From the white shark's viewpoint human beings are much more dangerous to it than vice-versa. Off California 10 to 20 or more white sharks are killed each year as a byeatch of fisheries, vs. 0.13 humans per year killed by white sharks. As the number of white sharks present in these waters is very small and probably vastly less than the horde of swimmers, divers, surfers, and other people at risk from white shark attack, the sharks are sustaining a greatly higher per capita loss from human attack than people are from them.
Size:
Maximum total length at least 640 cm and possibly to over 800 cm. Individuals captured are more commonly between 140 and 600 cm. Some males m.y begin maturing at about 240 cm, but adult males may reach about 550 cm.
A length-weight power curve for the white shark (98 specimens, mostly from California, and with a total length range from 127 to 554 cm) is as follows:
WT = 4.34 x 10 -6 TL 3.14
Interest to Fisheries:
Limited, as this species is nowhere abundant enough to support a significant fishery; mostly taken as a byeatch of fisheries of other sharks and other fishes, by longlines, hook-and-line, fixed bottom gillnets, fish traps, herring weirs, and trammel nets, harpoons, and even bottom and pelagic trawls, as well as purse seines. Important as a big-game sports fish in a few areas, especially Australia and the northeastern United Stated. Utilized fresh, dried salted, and smoked for human consumption; the liver oil is extracted for vitamins; the carcass used for fishmeal; the skin for leather; the fins for shark-fin soup; and the teeth and jaws for decorations, with properly prepared large jaws bringing a high price.
Type material:
Holotype: Unknown. Type Locality: "Europa".