Scientific name: Carcharodon carcharias
The (great) white shark is the most famed of shark species, known worldwide for its large size, predatory nature and reputation for occasionally attacking humans. It is recognizable by its immense size, conspicuously black eye and the sharp contrast between its backside and underside colouration changing from dark grey, or even black, to white. It has a heavy spindle-shaped body, a moderately long conical snout, and large triangular teeth with blade-like serrations.
At birth white sharks are between 1.09 m and 1.65 m. This large size at birth prevents predation from most marine animals. They ultimately grow to a total length of between 3.8 to 6 m and possibly longer, and typical lifespan of this apex predator is estimated between 23-60 years.
Distribution and Population
Worldwide, this species is rare but does occur with some predictability in certain areas. The white shark is widely distributed in sub-polar to tropical seas of both hemispheres, but it is most frequently observed and captured in inshore waters over the continental shelves of the western North Atlantic, Mediterranean Sea, southern Africa, southern Australia, New Zealand, and the eastern North Pacific. The species is not found in cold polar waters.
On both the Atlantic and Pacific coast of Canada, white sharks appear to occur sporadically, as there have been only 46 known confirmed or probable records between 1874 and 2006 (32 records in the Atlantic since 1874 and only 14 records since 1961 in the Pacific). White shark records from Pacific Canada consist almost exclusively of strandings on the Queen Charlotte Islands (Haida Gwaii) during late autumn and early winter months. Off Atlantic Canada, the white shark has been recorded from the Northeast Newfoundland Shelf, the Strait of Belle Isle, the St. Pierre Bank, Sable Island Bank, the Forchu Misaine Bank, in St. Margaret’s Bay, off Cape La Have, in Passamaquoddy Bay, in the Bay of Fundy, in the Northumberland Strait, and in the Laurentian Channel as far inland as the Portneuf River Estuary.
There are no estimates of population size in Canadian waters and there is a general lack of white shark population trend information worldwide, reflecting their rarity. Their abundance in Canada has likely always been much lower than in adjacent southern U.S. waters. However, there are several locations throughout the world with documented declines in population, and white shark numbers have been estimated to have declined by about 80% over 14 years in areas of the Northwest Atlantic Ocean outside of Canadian waters.
The white shark occurs in both inshore and offshore waters. It ranges in depth from just below the surface to just above the bottom, down to a depth of at least 1,280 m. It occurs in the breakers off sandy beaches, off rocky shores, and readily enters enclosed bays, lagoons, harbours, and estuaries, but does not penetrate mixed fresh and salt waters (brackish) or fresh waters to any extent.
Possible white shark pupping areas on the west and east coasts of North America include off southern California and the Mid-Atlantic Bight, respectively.
The species is highly mobile, and individuals in Atlantic Canada are likely seasonal migrants belonging to a widespread Northwest Atlantic population.
White sharks are an apex predator with a wide prey base feeding primarily on many types of fish, and marine mammals, as well as squid, molluscs, crustaceans, marine birds, and reptiles. There has, however, been one recorded occurrence of an orca preying on a white shark.
Age and size at maturity in white sharks varies regionally. Males reach sexual maturity at an age of 8 to 10 years and a length of 3.5 to 4.1 m, while females reach maturity at an age of 12 to 18 years and a length of 4 to 5 m. They are able to swim long distances over extended periods with an average cruising speed of 3.2 km per hour.
In reproduction, the female produces eggs which remain in her body until they are ready to hatch. When the young emerge, they are born live. Gestation period is unknown, but may be about 14 months. Litter size varies, with an average of 7 pups. Length at birth is assumed to be between 109 and 165 cm.
The white shark is a highly visual creature. Its curiosity about novel objects and activities at the surface, from boats to surfboards and rubbish, often brings it into contact with humans.
Humans are the most significant predators of white sharks, taking them as sport fish, commercial bycatch, and for international trade of their valuable body parts. However, in Atlantic Canada there are only two records of white sharks captured in fishing gear since 1990. In Pacific Canada, there are no confirmed records of white sharks caught by fishing activities. Several stranded white sharks on the Queen Charlotte Islands had markings that may have resulted from fishing gear. The white shark’s tendency to investigate boats and other floating objects often brings them to the surface, where they can be easily hooked, shot, or harpooned.
The celebrated cultural status of the white shark makes its jaws and teeth particularly sought-after as a collector’s item, and its fins for Asian delicacies and traditional medicines. An additional threat is the low reproductive rate of this species, which slows its ability to recover from earlier losses.
Courtesy of Species at Risk Public Registry