Sailors are among those perfectly placed to witness the extent of marine life in UK and Irish waters. That includes sharks of various species, of which there are at least 21 permanently resident, 11 deep-water visitors, and several more than might drop by once in a while. Of all shark species that do put in an appearance around the British Isles, at least half are in danger.

basking shark

Above: basking shark

There are probably two reactions to sharks: either terror (accompanied by the theme to a certain movie and the sudden urge to get a bigger boat) or wonder (these are, with some exceptions such as the basking shark, creatures of sublime elegance and grace).

If you happen to be in British waters, terror is certainly an over-reaction. There have been no unprovoked shark attacks around the UK and Ireland since records began in 1847. And, while fishermen sometimes report sightings of great white sharks close to southern England, there’s really no hard evidence that supports such claims. As the Shark Trust notes, “The closest confirmed report was of a female white shark, captured in 1977 in the northern Bay of Biscay – 168 miles off Land’s End, Cornwall. In 2014, a tagged white shark called Lydia was documented as the first of her species to cross the Mid-Atlantic Ridge, although she was still 1,000 miles from British shores”.

So, let’s for argument’s sake react in wonder instead of fear, look at some of the species that frequent British waters, and find ways to protect them.

If you spot a shark that’s native to the British Isles, it’s probably going to be a dogfish of one kind or another. They favour the south and west coasts; although fairly common and happy to eat almost anything, some dogfish are considered vulnerable by the International Union for Conservation of Nature. In fact, research revealed in September this year that some endangered species of dogfish were being passed off as rock salmon in British fish and chip shops. A visit to the beach should give you an idea of whether there are dogfish nearby, as their egg cases (called mermaid’s purses – see image below) commonly wash up on shore. Among British dogfish is the spurdog, which Bristol Aquarium notes is one of the very few venomous fish to be found in these waters.

mermaids purse

Dogfish don’t look that much like the common image of the shark (and nothing at all like dogs) – but common smooth-hounds do. They are also native to British waters and, like some dogfish, are considered vulnerable. Even more “sharky” are tope (below), which can grow up to around two metres long. They find their homes around the British Isles, but are also migratory – roaming anywhere between the Canary Islands and Iceland. The Marine Conservation Society states that topes are protected in England, Scotland and Wales; they have in the past been hunted for their liver oil, and are threatened by underwater cables across their migration routes, and damage caused by trawling.


One once-populous British shark that sailors are unlikely to encounter today is the angelshark. It’s been hunted to near extinction since the 19th century, when it was extremely common off the western coast of Great Britain. The angelshark is listed as critically endangered by the IUCN, and if you do see one you are urged to report in as much detail as possible to the MCS.

Among the vistors, the biggest (in fact, the second biggest fish in the world) is the basking shark. These fish visit British waters between May and October, and can be seen off the coasts of Cornwall, western Wales and western Scotland. They are a protected species (classified as vulnerable by the IUCN), which the Marine Conservation Society notes can grow up to 12 metres long (for reference, consider how long your boat is), and feed by simply swimming along with their mouths open, taking in plankton. Basking sharks are definitely not a direct threat to humans, though if you’re sailing in their favoured waters during the season do keep a good look-out for their fins flopping about on the surface; a collision isn’t going to do either of you any good.

shortfin mako

Other visitors include shortfin mako sharks (above). If you are lucky enough to spot one of these, it could be that they are chasing tuna into British waters. You might not see it for long, though, as shortfin makos can travel through the water at close to 50 knots (again, compare this with your boat). In August 2019, makos were added to the Convention on International Trade in Endangered Species to the vulnerable list.

Other known, though less common visitors to British waters include the thresher shark and the Greenland shark. Of these, the Marine Conservation Society suggests that threshers might be spotted closest to shore (though they are not a direct risk to humans). The Greenland shark (below) would be a rare sight indeed, as it favours very deep waters and seems particularly adept at evading humans (which could account for its suspected life-span of around 400 years). Henry William Dewhurst recorded a very interesting observation about the Greenland shark in 1834, writing: “The pieces that are cut off exhibit a contraction of their muscular fibres for some time after life is extinct. It is, therefore, extremely difficult to kill, and unsafe to trust the hand within its mouth, even when the head is cut off”.


The IUCN lists thresher sharks are declining in numbers and vulnerable, and Greenland sharks as near-threatened. In 2018, members of the Northwest Atlantic Fisheries Organisation agreed a ban on deliberate fishing for Greenland sharks.

The Shark Trust says that these fish are a vital part of marine ecosystems, and allowing species to die out could have negative consequences on the sea environment. To find out more, and to learn how you can get involved with shark protection work in many ways, visit the organisation’s website here.

One thought on “Environment: fancy sailing with sharks? British Waters might be a good place to start

  1. Anthony Casey is SailHo solely your blog? Are all the recent posts written by you, like this one about Sharks or the one about Exmouth Harbour etc? Or is Sailho a group you belong to with others adding their stories. All I have read so far, is well written, very interesting and factual and as soon as I see the Sailho Logo I know there is going to be something worthwhile to look at. Thank you. Kevin Mitchell.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s