Granddad’s Camera
Basking shark, as it appears in the game

No.066 · Fish · Very rare

Basking shark

Cetorhinus maximus

Britain's biggest fish: a harmless plankton-feeder that cruises slowly at the surface with its enormous mouth open.

When to look

June to September, mostly at day.

Time of day

Best time
Calm, sunny days in summer: May–October.
Where in the game
the Pembrokeshire coast (sea)
Size
Up to 12 m (the largest recorded)
Weight
Average about 4.5 tonnes, up to 7 tonnes
Lifespan
Thought to live at least 50 years (Shark Trust)
Population
Not known for the UK. Heavily fished in the north-east Atlantic from 1946 to 1995 (Shark Trust)
Status
Endangered (IUCN Red List; Shark Trust)

Diet

Plankton, filtered through comb-like gill rakers as it swims with its mouth wide open

Habitat

Headlands, islands and bays with strong tidal flow, where plankton gathers; deep water in winter

Breeding

Females keep the eggs inside their body until they hatch, then give birth to fully developed young about 1–2 m long. Pregnancy is thought to last around 14 months; males mature at 12–16 years and females at about 20

Field signs

  • A tall, triangular dorsal fin and a tail tip slicing the surface
  • A huge shape moving slowly just below the water
  • Sometimes an open, cavernous mouth and long gill slits
  • Often seen on calm days, singly or in groups

Did you know?

  • A basking shark is as big and heavy as a double-decker bus, yet lives entirely on plankton (Pembrokeshire Coast National Park).
  • Satellite tags showed that basking sharks do not hibernate in winter: they move to deeper water and feed on deep-water plankton (Shark Trust).
  • Despite their size, basking sharks can leap clear of the water; Pembrokeshire's sharks seem to move up the Irish Sea towards the Isle of Man.

Moments worth waiting for

  • Surface feeding June to August, day
    A huge triangular fin and tail tip cruise slowly through the calm water, the shark's mouth agape to sieve plankton.

Photo tip

Look for a slow-moving fin on a flat sea, then shoot from a steady boat or a headland with a polarising filter to cut glare and see the shape below. Keep the shutter fast for a rocking boat and hold back to give it space.

Be a good naturalist

Basking sharks are protected under Schedule 5, and intentionally harassing one is a criminal offence. Follow the Shark Trust code: stay at least 100 m away, keep below 6 knots, put the engine in neutral inside 100 m, keep at least 500 m from courting groups and never chase or touch a shark. Use a WiSe-accredited operator and report sightings to the Shark Trust.

The law

Schedule 5 of the Wildlife and Countryside Act 1981: it is illegal to intentionally kill, injure or harass basking sharks in British waters, with up to 6 months in prison and a large fine (Shark Trust). Also CITES Appendix II

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