The basking shark, is the second largest living fish, after the whale shark. It is a cosmopolitan species — it is found in all the world's temperate oceans. It is a slow moving and generally harmless filter feeder.
Like other large sharks, basking sharks could some day be at risk of extinction due to a combination of low resilience and overfishing if good conservation practices are not followed.
The basking shark is a coastal-pelagic shark found worldwide in boreal to warm-temperate waters around the continental shelves. It prefers waters between 8 and 14° C. It is often seen close to land and will enter enclosed bays. The shark will follow concentrations of plankton in the water column and is therefore often visible on the surface. They are a highly migratory species leading to seasonal appearances in certain areas of the range.
The basking shark is a passive filter feeder, filtering zooplankton, small fish and invertebrates from up to 2,000 tons of water per hour. Unlike the megamouth shark and whale shark, the basking shark does not appear to actively seek its quarry, but it does possess large olfactory bulbs that may guide it in the right direction. Unlike the other large filter feeders, it relies only on the water that is pushed through the gills by swimming; the megamouth shark and whale shark can suck or pump water through their gills.
Studies in 2003 have disproved the idea that basking sharks hibernate and have shown that they are active throughout the year. In winter, basking sharks move to deeper water (depths of up to 900 m) feeding on deep water plankton. Satellite tagging confirmed that basking sharks move thousands of kilometres during the winter months locating plankton blooms. It was also found that basking sharks shed and renew their gillrakers in an ongoing process, rather than over one short period.
They feed at or close to the surface with their mouths wide open and gill rakers erect. They are slow-moving sharks and do not attempt to evade approaching boats. They are harmless to humans if left alone and will not be attracted to chum.