Basking shark Cetorhinus maximus

The basking shark is the second largest fish in our oceans – its relative the whale shark being the biggest. The large, black, triangular dorsal fin moves slowly through the water, with the tail tip or snout sometimes visible above the waves, too. The basking shark has a massive, grey body that can be longer than a bus!


Despite their size, basking sharks actually feed on plankton which they filter out of the water, swimming slowly back and forth with their enormous mouths wide open. They are most commonly seen in the summer, when they gather in British waters. Try looking from cliffs or boats offshore in the south and west.


  • Length: up to 12m
  • Weight: 6 tonnes
  • Average Lifespan: anything from 20-100 years


Classified as Endangered on the IUCN Red List, listed under CITES Appendix II and classified as a Priority Species in the UK Biodiversity Action Plan.


Found all around our coasts, but most frequently seen around the west coast of Scotland, the south-west of England, Wales and the Isle of Man

When to see

May – September


  • The basking shark may be huge but it disappears from the coast in winter, completely foxing scientists as to its whereabouts! Theories include everything from hibernating in deep water to shedding their gill rakes (which help them to feed), but satellite tracking shows that they migrate during all the seasons, so are always on the move.
  • Basking sharks were hunted in Scotland up until 1994 for the oil in their livers that was used to make cosmetics, perfumes, lubricants and as lamp oil.

Common name

Basking shark

Species name

Cetorhinus maximus

IUCN Red List status


When to see in Scotland

May – September

Where to see in Scotland

Scottish Wildlife Trust reserves such as the Isle of Eigg

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