Are There Great White Sharks in the UK? The Evidence

What the evidence shows

The great white shark lives in temperate seas around the world, including the Mediterranean and the northwest Atlantic, so a visit to Britain is not far-fetched. Yet the UK charity the Shark Trust, which collects shark records, says there have been no confirmed sightings and no strong evidence that great whites occur in British waters. It describes their presence as very unlikely, though not impossible.

The closest confirmed record is a female great white caught in 1977 in the northern Bay of Biscay, off the west coast of France, roughly 270 km (168 mi) from Land’s End in Cornwall. In 2014, a great white named Lydia, tagged by researchers off Florida, crossed the Mid-Atlantic Ridge into the eastern Atlantic, but she was still about 1,600 km (1,000 mi) from British shores.

Credible sightings and famous claims

Many people have reported great whites off Britain, especially off Cornwall and Devon in summer. Shark researcher and author Richard Peirce, who spent years investigating these claims, looked at nearly 100 reports and judged about 12 of them credible, possibly as few as seven. They range from Falmouth in Cornwall in 1965 to the Isle of Lewis in the Outer Hebrides in 2016.

A credible report is still not a confirmation. Seeing a large fin at sea for a few seconds is rarely enough to identify a species, and none of these sightings came with the kind of evidence scientists require, such as a clear photo of the head and teeth, a DNA sample or a satellite tag. Tabloid stories of “Jaws in Cornwall” appear most summers, and most turn out to involve other sharks, dolphins or even ocean sunfish, whose fin can break the surface.

Could great whites live in British waters?

On paper, British seas look suitable. A University of Plymouth study that compared sea temperatures with tracking data found near-perfect conditions for great whites around the UK all year round. Great whites often favor water around 16 °C (61 °F), close to summer and autumn temperatures off southwest England, and they can tolerate much colder and warmer water.

There is also plenty of food. The UK has more than 90,000 gray seals and about 43,000 harbor seals, as well as large shoals of mackerel and herring. Seals are a favorite prey of adult great whites elsewhere, for example off Cape Cod in Massachusetts.

So why are there no confirmed records? The nearest populations are small or far away. Great whites in the Mediterranean and other European waters are assessed by the IUCN as Critically Endangered, with fewer than 250 mature sharks thought to remain. The northwest Atlantic population mostly moves up and down the coast of North America. The Plymouth study suggested that any visitor would most likely be a male from the Mediterranean population, which might spend much of its time deep below the surface and go unnoticed.

Look-alikes: what people really see

Most “great white” sightings in Britain turn out to be other sharks. Over 40 shark species have been recorded around the British Isles, and at least 21 live there all year.

Basking shark. By far the most common source of mistaken reports. The basking shark is the second-largest fish in the world, regularly 7–8.5 m (23–28 ft) long, and visits the coasts of Cornwall, the Isle of Man, western Scotland and Ireland mainly from May to October. It swims slowly at the surface, so its tall, triangular dorsal fin and the tip of its tail can both show above the water, which can look alarming. Up close, its enormous open mouth and huge gill slits are unmistakable. When to see them is covered in When do basking sharks visit the UK?

Porbeagle. The porbeagle (Lamna nasus) belongs to the same family as the great white and looks like a smaller version of it, with a stout gray body, pointed snout and crescent-shaped tail. It usually grows to about 2.5 m (8 ft), and the heaviest on record, caught off Caithness in Scotland in 1993, weighed 230 kg (510 lb). A white patch at the back of its first dorsal fin and a second small keel on each side of the tail help tell it apart. The IUCN lists it as Vulnerable worldwide and Critically Endangered in the northeast Atlantic.

Blue and shortfin mako sharks. Slender blue sharks are common offshore in summer, and the shortfin mako, a fast relative of the great white, is an occasional visitor. Both live far from the beach.

What to do if you see a large shark

The chance of meeting a great white in Britain is extremely small, and none of Britain’s regular sharks are known for biting people. Shark bites in UK waters are extremely rare. Basking sharks are harmless, as explained in Are basking sharks dangerous?, but they are protected by law, so boats and swimmers should keep their distance and never chase or touch them.

If you see a large shark, try to take a clear photo or video showing the dorsal fin, head and tail, note the time and place, and report it to a recording scheme such as the Shark Trust’s. Good records are exactly what scientists need to settle whether great whites ever reach British waters.