The following is a list of significant conservation developments over the past ten years. The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species.
In the western Atlantic, it ranges from Newfoundland to Florida and southern Brazil to Argentina and from Iceland and Norway to Senegal, including the parts of the Mediterranean in the eastern Atlantic. The basking shark is typically seen swimming slowly at the surface, mouth agape in open water near shore.
This species is known to enter bays and estuaries as well as venturing offshore. Basking sharks are often seen traveling in pairs and in larger schools of up to a or more. Basking sharks are highly migratory. Off the Atlantic coast of North America it appears in the southern part of its range in the spring North Carolina to New York , shifts northward in the summer New England and Canada , and disappears in autumn and winter.
Off the southwest coast of the United Kingdom in the northeast Atlantic, the basking shark feeds at the surface of coastal waters during the summer. These sharks are absent from November to March, suggesting a migration beyond the continental shelf during the winter months. This is explained by the high zooplankton density the primary food of the basking shark that exists in these waters during late spring and early summer.
Sightings of groups of individuals of the same size and sex suggest that there is pronounced sexual and population segregation in migrating basking sharks.
Distinctive Features The basking shark is one of the most recognizable of all sharks. Its massiveness, extended gill slits that nearly encircle the head and lunate caudal fin together help distinguish it from all other species.
It possesses a conical snout and numerous large gill rakers modified for filter feeding. Its enormous mouth extends past the small eyes and contains many small, hooked teeth. The liver is high in squalene, a low-density hydrocarbon that helps give the shark near-neutral buoyancy. Coloration Dorsal surface is typically grayish-brown but can range from dark gray to almost black.
Ventral surface may be of the same color, slightly paler or nearly white. Dentition The basking shark possesses hundreds of tiny teeth. Those in the center of the jaws are low and triangular while those on the sides are more conical and slightly recurved.
There is typically a wide space on the center of the upper jaw with only scattered teeth. Size, Age, and Growth Second only to the whale shark Rhincodon typus in size, the basking shark can reach lengths up to 40 feet 12 m. The average adult length is feet 6. Size at birth is believed to be between feet 1. The basking shark is an extremely slow-growing species and may grow to feet m before becoming mature. Food Habits Along with the whale shark and the megamouth shark Megachasma pelagios , the basking shark is one of three species of large, filter-feeding sharks.
However, the basking shark is the only one that relies solely on the passive flow of water through its pharynx by swimming. The basking shark is usually seen swimming with its mouth wide open, taking in a continuous flow of water. The whale shark and megamouth shark assist the process by suction or actively pumping water into their pharynxes.
Food is strained from the water by gill rakers located in the gill slits. These sharks feed along areas that contain high densities of large zooplankton i. This species is typically found within the ocean over the continental shelf and slope, but may winter in deeper offshore waters where they continue to feed on deep-water plankton. Basking sharks are filter-feeders feeding near the base of the food chain on zooplankton, especially on small crustaceans known as copepods.
They have been observed feeding in large groups when ample food is available. In portions of its range, basking sharks show strong sexual segregation, with females far outnumbering males, or vice versa. Very little is known about their reproduction but it appears that their reproductive rate is very low. It is estimated that females may give birth somewhere between every 18 months to 3 years, with litter sizes of young. Basking sharks are ovoviviparous. Age of sexual maturity and life span are unknown, though it is believed that they may live for at least several decades.
Despite their large size and slow swimming speed, basking sharks have been known to breach, jumping entirely out of the water, for reasons unknown.
Their only known predator, aside from humans, are killer whales. The basking shark is considered a Species of Concern by the federal government within the eastern North Pacific Ocean from Alaska to California. It currently has no federal status within the Atlantic Ocean nor does it have any New Jersey state conservation status. Though it has no legal conservation status in New Jersey, it is still illegal to take, possess, land, purchase, or sell them within the state.
The basking shark has been fished commercially as a source food, fins, and liver oil. Ireland in discussions with Biden administration over UK Article 16 plans. Subscribe Now. Lunchtime News Wrap. Sign Up. Puzzles hub Visit our brain gym where you will find simple and cryptic crosswords, sudoku puzzles and much more.
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