Thorny spider crabs found off North Norfolk coast
06:30 July 27, 2022
Fishermen in North Norfolk have caught unprecedented numbers of a species of crab native to warmer southern waters – another sign of the impact of climate change on the county.
The spiny spider crab, normally found in the Mediterranean Sea, the northeast Atlantic and the south and west coasts of England, has migrated north due to warming sea temperatures.
Previously it was rare to catch one in the North Sea – but this year they have appeared in the traps of anglers from Cromer to Weybourne.
John Davies, 57, a fisherman from Cromer, said: “It’s a fairly new phenomenon. We’ve had one or two before but this year there seems to be a lot more.
“I caught numbers in my mid-teens where before you never saw one.”
Another Cromer fisherman, Henry Randell, said: “A spider crab caught off the coast was extremely rare.
“You might get one or two along the coast. If you caught one, people would talk about it.”
Mr. Randell, who is 28 and has been fishing for 12 years, had never seen one before.
“But I caught eight myself this year,” he said.
“The equipment we use is not for the spider crabs, they can’t get into the traps as easily, so what we catch is only a fraction of what’s out there,” he said. he added.
In the South West of England there is a commercial fishery for spider crabs, with most of the catch being exported to France and England.
But Mr Randell said that for such a fishery to develop in North Norfolk, fishermen would need to change all their gear.
“We don’t want to see spider crabs because we’re fishing for brown crabs,” he said.
“Are we going to see more and more of them every year? Are they going to take over? That’s the concern.”
Mr Davies, who has been fishing from his own boat for 40 years, does not believe the spider crabs will have a major impact on the region’s crab and lobster fishing industry.
“I don’t think they will have any effect,” he said. “They’re not as strong as our crabs. I imagine our traditional crabs will handle them quite easily.”
He said, however, that the habits of Cromer crabs have changed slightly over the years and that warmer waters mean they don’t hibernate as long as they used to.
Alastair Grant, professor of ecology at UEA’s School of Environmental Science, said: “Spider crabs are more commonly found in the south and west of the British Isles.
“Climate change is leading to warmer sea temperatures and for some time now fish and shellfish have been expanding their geographic ranges northward. It is therefore not surprising that spider crabs are starting to appear on the Norfolk Coast.”
Mr Grant also predicts that the spider crab will ‘co-exist with our more familiar Norfolk species, just as in the South West of England’.
Chris Taylor, a Sheringham-based photographer who frequently dives in the waters off the north coast, said the appearance of the spider crabs ‘happens quite quickly’ and most of them have been caught offshore of West Runton.
The anglers he spoke to didn’t catch any last year or the year before, but did catch several spider crabs this year.
Mr Taylor has yet to see any himself this year, but said he wanted to film them.
An indication of the apparent suddenness of spider crabs appearing around Norfolk is a page on the Wildlife Trust website which says the crustaceans are “absent” from the North Sea.
“Low chance of taking over”
Ron Jessop, senior marine science officer at the Eastern Inshore Fisheries and Conservation Authority (IFCA), based in King’s Lynn, said the number of spider crabs found on the north Norfolk coast is “still low” compared at the South West.
“Fishermen catch one or two a day, not tens or hundreds,” he said.
Responding to concerns that spider crabs could displace the brown crab, known locally as the Cromer crab, Mr Jessop said he had spoken to colleagues in the South West who had seen no indication that spider crabs take over.
He said it was possible the spider crabs are currently migrating to the coast as they normally live in deeper water.
“They might compete for food with brown crabs, but we don’t see the numbers that would indicate that’s happening,” he said.
“Normally spider crabs won’t outcompete brown crabs,” he added. “Spider crabs are slow-moving, less hardy, and less aggressive than brown crabs.”
Cromer crabs are brown crabs, scientifically known as Cancer pagarus. They are found from Scandinavia to Portugal and have been caught off the North Norfolk coast for centuries.
They are transported with traps during the crabbing season which spans eight months of the year, peaking, depending on the weather, from March to July.
The spider crab, on the other hand, is also known as the European spider crab, or its scientific name of Maja squinado.
It is tall and orange with long spindly legs (hence its name) and a body up to 20cm long.
They eat algae, mussels and starfish.
It is a migratory crab, traditionally found in the northeast Atlantic and the Mediterranean Sea.
They migrate in autumn from shallower coastal waters to the deeper sea offshore and back, with some crabs traveling 100 miles in eight months.