French mussel farmers have said voracious spider crabs that have infested the country’s western coast are destroying their shellfish and livelihoods as warming seas allow the migratory animals to spend more of the year offshore.
Angry producers in Normandy and Brittany are demanding to be allowed to control crab numbers by killing them or using dredging nets to drag those ravaging their mussel “parks” further out to sea.
They believe the climate crisis leading to the warming of the sea in the Channel has meant the normally migratory European spider crabs – who have few predators – are remaining offshore for much of the year instead of only one or two months.
The producers warn that unless the crabs are culled or curbed mussel production could end in the region within a decade.
Thousands of spider crabs were reported on beaches in Cornwall in August linked to rising sea temperatures. Harmless to humans, the crabs, measuring up to 20cm wide, are scavengers feeding mostly on plant matter and shellfish. They usually migrate in great numbers into deeper water over several months.
“They are like a carpet moving slowly across the seabed ravaging anything on the ground and leaving nothing in their wake,” Vincent Godefroy, the president of the National Mytiliculteurs (mussel farmers) Group based in Normandy said.
“We first noticed the problem around five years ago. Since then the population seems to have doubled every year. There have always been crabs around the Normandy and Brittany coast but usually only for a month or two. Now they are there all year round and they are voracious eaters of everything: shellfish, fish, eggs, everything. Their only predator is man.”
Although spider crabs can be eaten, the numbers off the coast far outstrips demand, he added.
Godefroy represents 300 mytiliculteurs (mussel farmers), many of whom are struggling with increased losses as the crabs scale the posts lodged in the sea bed on which the shellfish grow. He said their production of these moules de bouchots (the bouchot being the post) classified as as a traditional speciality guaranteed by the European Union, is vital for the local economy.
“There’s not much else around here,” he said. “We can’t resolve the problem ourselves because we don’t have authorisation to do anything about it. We’re not asking the government to it for us or to give us a centime; all we are asking is that we are allowed to find a solution.”
He is vague about what that might be. “We’re told that in the UK you’re allowed to kill them, but we can’t say that or we will upset the ecologists. The population has to be regulated somehow. At the moment we are allowed to try to catch them, but we have to put them back in the sea. Often they’re back the next day,” he said.
“We have been using plastic nets to protect the mussel cages but putting plastic into the sea isn’t great for the environment either. There is no miracle solution, but we have to find a way to keep them away from the coast.”
Godefroy added: “If the government won’t allow us to save our livelihoods then it must pay us compensation for our losses.”
David Dubosco, a mussel farmer, said he had lost 150 tonnes of the shellfish to the hungry crabs this year alone. “It’s getting worse and worse. It’s an invasive species,” he told TF1. “It’s growing all the time and we can’t see a way out of it.”
Anthony Mahe, another producer, added: “Normally the season lasts until mid-January. This year, after the end of November we won’t have any more mussels. If we don’t find a solution, if the state doesn’t help us regulate this invasive species, we’re condemned to disappear,” he said.
In a protest outside the Manche préfecture at Saint-Lô last week, 70 mussel producers protested with a coffin symbolising the end of their production.
Godefroy says allowing his members to control the spider crab population is the same as allowing hunters to hunt wild boar on land to protect farms.
The préfecture responded with a statement saying it would allow “new measures to be tried out” to combat the crabs, including dredging the sea bed around mussel farming concessions.
“These emergency measures will be assessed in November at a forthcoming meeting between mussel farmers’ representatives and the prefecture,” it added.
