As if the all-to-real dangers of Morecambe Bay’s tides and weather often isn’t bad enough, now the Morecambe Bay Partnership is warning the public to be on the look out for monster crabs that look like they’ve come straight out of a 1950s B-horror movie.

The Chinese Mitten crab is no joking matter, though, according to Natural England: it’s a highly invasive — one of the world’s worst invasive species, arriving here through a combination of escaping from ship’s ballast water, hull fouling, live food trade and smuggling  — and is damaging to both ecology and the economy.

A UK resident for at least three-quarters of a century, first sighted in the Thames in 1935, they’re easy to spot as they’re quite big, with carapaces up to four inches in size, with large furry front claws.

These monster crabs – which have been sighted in Cumbria – have caused immense economic and ecological damage, to unprotected river banks, blocking water systems, damaging fishing gear and competing with native species for food and habitat.In the right conditions, notes the Natural History Museum, the mitten crab multiplies and spreads at an astonishing rate and can even leave the water, cross dry land and enter a new river system.

Its phenomenal ability to disperse is of concern to scientists in the UK who say that because the crab could infiltrate many of the country’s rivers they now need help recording sightings in the UK.

Beach clean volunteers, anglers, waterway workers, boating enthusiasts and nature lovers may be the most likely to come across these crustaceans, but anyone can record a sighting online or by telephone, email or text. 

Image provided by Natural England

© Natural History Museum

Although there have been no reported sightings locally so far, two females were found at Millom Pier in 2005 and local environmentalists hope this means they are no longer present. But the fear is they may be under recorded.

The good news is, there may actually a use for these devilish creatures: The Ecologist noted last year that they’re considered very good to eat. So as well as being the size of a dinner plate, you might find them on it. The crab’s gonads are considered a delicacy worth paying high prices for and celebrity chef Gordon Ramsay, who featured mittens in an episode of Channel 4’s The F Word last year, pronounced the flesh sweeter and more intense in flavour than typical crabmeat.

No legislation exists that allows mittens to be fished commercially, but the Environment Agency has a duty to regulate and improve fishing for certain species, including mittens, since the introduction of the Marine and Coastal Access Bill, which came into force in January last year.

In addition, a licensing and authorisation process is currently underway that from January this year requires anyone wanting to catch the crabs to obtain EA permission to do so. There are other area-specific agencies involved, however, including the Port of London Authority, which owns the Thames riverbed.

• Report sightings by text or picture message to 07806 938789 or online at www.mittencrabs.org.uk

• Further info on this page from the Natural History Museum: www.nhm.ac.uk/about-us/news/2011/september/help-scientists-record-invasion-of-chinese-mitten-crabs102396.html

RAFTS Biosecurity Invasive Species Programme

• The Ecologist: How to protect UK rivers from invasive mitten crabs, and eat locally as well!

• Morecambe Bay Partnership: www.morecambebay.org.uk