« Back to Wildlife protection
All about basking sharks - the facts
The basking shark (Cetorhinus maximus) is Britain’s largest fish. They can grow up to 11 metres long and weigh up to 7 tonnes - about the size and weight of a double-decker bus! Once numerous in our waters, basking sharks were hunted for their liver oil and their populations declined to such an extent that now they are considered to be endangered in UK waters.
The basking shark (Cetorhinus maximus) is the second largest fish in the world, the only fish growing bigger is the mighty whale shark (Rhincodon typus), which can reach lengths of 20 metres and weigh up to 34 tonnes!
The basking shark (Cetorhinus maximus) is a member of the lamnid family of sharks, which includes the notorious great white shark (Carcharodon carcharius). There are 21 other species of shark recorded in UK waters.
Despite their enormous size they are not dangerous to humans. They feed on plankton, using their gill rakers to filter feed, and have only tiny teeth. When feeding, basking sharks filter about 2,000 cubic meters of water per hour through their enormous mouths, about the same volume of water it takes to fill an Olympic-size swimming pool!
Basking sharks can take 12-20 years to reach maturity. Little is known about their reproduction, but adult female basking sharks give birth to live young, and only about once in every four years. Gestation is thought to take up to 3 years and a litter may consist of 5-6 pups. This life history makes basking shark populations extremely vulnerable to over fishing.
The Marine Conservation Society (MCS) is a lead partner of the UK Government’s Basking Shark Species Action Plan steering group. Our Basking Shark Watch project started in 1987 and has generated the largest database of surface sightings of basking sharks in the world.
