A sailor's guide to UK sharks and fish

Genevieve Leaper looks at some of the shark species around the British and Irish coasts and how to spot these fish from your boat

- Genevieve Leaper

Everyone loves a dolphin and bird-watching is a popular activity but what about the largest group of vertebrate animals? Fish are poorly known and sadly under-appreciated except perhaps on the dinner plate.

Many sailors can probably recognise a mackerel but few people regard fish as interesting animals to observe. There is an amazing variety of fish with two main groups - the cartilaginous fish, comprising sharks, skates and rays-and the more numerous bony fish. Of course, to see most of the 300+ species that inhabit UK coastal waters you'd need to enter their underwater realm. But there are fish that can be seen at the surface and they tend to be big and impressive.

Basking shark

Better still, the one you're most likely to see is the biggest. The basking shark is the second largest fish on the planet, 2m long at birth and growing to 10m or more. Only the whale shark, a fellow plankton feeder, is larger.

Basking sharks visit us in summer, appearing first off Devon and Cornwall and the south coast of Ireland from around April, reaching the Isle of Man and Scottish waters by the end of May. July and August are generally the best months to see them in the Hebrides although sharks may be present until October. Hebridean hotspots include Coll and Tiree, Canna, west Skye and the Outer Isles. Malin Head in Ireland is another good location. The sharks come inshore to feed on the abundant plankton, sometimes very close to shore-I've even seen one in Canna harbour.

Basking sharks are not difficult to observe when they're on the surface. The first thing you'll see is a big, triangular dorsal fin, which can be 1m high and rather floppy. The tail fin is a different shape but can fool you into thinking there are two animals as it waves around. The nose of a feeding shark may also be visible as a rounded lump.