Since 2006, a species of blue crab native to the West Atlantic has started to be detected in numbers on the Albanian coast: it is the Callinectes sapidus, whose flesh is known to be delicious.

But the crustacean is also known to be very voracious and aggressive, so much so that it is now one of the 100 most invasive species in the Mediterranean and the Adriatic.

This year, it has particularly proliferated in Albanian waters, to the great misfortune of the local fishermen: "We, the fishermen, are very worried, because the blue crab has swallowed everything, it destroys the nets, the fish, the eels of our waters have completely disappeared, "Stilian Kishta, an Albanian fisherman, told AFP on July 24.

Callinectes sapidus has also been spotted on part of the French and Spanish coasts. But for the moment, the situation is not yet critical, according to Christine Pergent-Martini, specialist in coastal ecosystems: "In France, we are content to follow these populations, to see if they are spreading, and if they pose or not particular problems in the new environments in which they arrive, ”she explains.

The Tunisian example

Tunisia for its part first faced another blue crab, cousin of Callinectes sapidus: Portunus segnis, from the Indo-Pacific region. In 2014, its proliferation began to become problematic.

Destroying everything in his path, he was nicknamed "Daesh" by Tunisian fishermen. The latter have expressed their concern on numerous occasions and, in 2017, the State reacted by launching a plan to exploit and develop this crab. 

Fishermen were trained to exploit the species, which was not fished before. Collapsible multipurpose traps, more effective at catching it, were provided, and the government began to subsidize the purchase price, providing financial assistance for every kilogram caught and sold.

Factories have also started producing frozen crab for export, particularly to the Gulf and Asia, where demand even exceeds supply.

Today, these exports constitute the majority of the profits made from the sale of Portunus segnis. Crabs are also sold in markets in coastal Tunisian towns, but remain uncommon in the rest of the country.

A new, more aggressive crab

The measures taken have helped stabilize the population of the species. But Marouene Bdioui, a researcher at INSTM, confides that he is now worried about the arrival of Callinectes sapidus on the Tunisian coast.

"It seems to me that this species is more valuable, there is more flesh in the Callinectes, but it is also a very aggressive species, he specifies. If the Tunisians find the Portunus segnis aggressive, the Callinectes is for me ten times more aggressive. Its claws are larger, more robust ... This species should be treated much more carefully than the Portunus segnis. "

The researcher has already been contacted by European colleagues to discuss the measures to be taken in the face of the proliferation of blue crabs. For him, this mutual aid is essential. Faced with this scourge, "all the Mediterranean countries must act hand in hand", he assures us.

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