Originating from the western Atlantic shores and the Gulf of Mexico, the blue crab (Callinectes sapidus) was first detected in Europe as early as 1901, in Rochefort (France), but it has only in recent years become established on a massive scale in the Mediterranean.
In Spain, it was first spotted in the Ebro Delta, in 2012, a habitat where the giant crustacean has found a perfect place to stay and develop; but it is already a major problem along the entire Catalan coast and has reached Andalusia and Mallorca, aided by the warming of the waters.
Over the years, the increase in its population has been constant. And its presence causes multiple problems. Voracious, capable of eating crustaceans, fish, mollusks, algae and even carrion, the blue crab poses an issue on several fronts: it competes for fishermen’s bait, hindering fishing and the catching of other crustaceans; it destroys all kinds of crops, such as mussels or clams; and, to top it off, it displaces other local crustaceans of greater commercial interest.
A crab that wipes out everything
The problem is not exclusive to Spain. In Italy, where the blue crab settled earlier (the first specimen was registered in the 1940s), they have been grappling with its attacks on mussel and oyster farms for years, but the outbreak has intensified due to climate change.
The area most affected is the northern Adriatic Sea; there, Daniela Borriello, director of the national fishing division at Coldiretti, the main Italian farmers’ association, told La Voz de Galicia that oyster production has plummeted by 80%: “The jobs of about three thousand people are in danger.”
Oyster and mussel farmers have tried everything to protect nurseries, fortifying them with nets that rise up to a meter and a half above the water surface, but blue crabs climb with astonishing ease and even scale these barriers.
Although, as in Spain, consumption is being encouraged to reduce the population, cooking them is not enough. The solution is likely to come from another route: starting to cultivate another species of bivalve that can withstand the blue crab’s onslaught. The oysters.
Could the blue crab democratize the oyster?
In recent years, the coastal regions of Veneto and Emilia-Romagna have been transforming much of their mussel and clam farming into oyster farming.
Although blue crabs also attack this bivalve, there are varieties with a particularly thick shell that stand up better to crab assaults.
The problem with oysters is that they are considerably more expensive and Italians are not as used to eating them: for starters, they are not typically used in pasta dishes, as is common with mussels or clams. So, as aquaculture companies push production, the government is trying to boost consumption.
The Italian Minister of Agriculture, Francesco Lollobrigida, has been campaigning for months to significantly raise oyster consumption. According to his plan, oysters should shed their luxury image and become affordable for a broader segment of the population. To that end, he is even prepared to cut their VAT to 10%, from the current 22%, as a luxury good.
“Oysters are a luxury good because they are expensive, not because nature has made them luxurious,” the Minister said in remarks to the press. “The commitment we have undertaken is to reduce the VAT to counteract the price, putting as many users as possible in a position to buy this product. Oysters should not be considered a luxury good, because they are a healthy product that stems from the valuable work of oyster farmers. In this case, of course, we are talking about farmed oysters, which can help create wealth and income for these sectors that are strategic and important for us.”
Galicia, for now, is spared
To date, the blue crab is not yet a problem in Galicia’s estuaries, where the majority of Spain’s crustacean and bivalve production is concentrated, but scientists have been warning for years that they could arrive at any moment.
“A massive invasion of blue crabs would cause enormous ecological and economic damage,” stated Juan E. Trigo, a member of the Galician marine environment study group (GEMM), already a decade ago. “It is a major predator of bivalves and, if it spreads, a very serious competitor for native crustaceans such as the nécora, the boi and the centolla; being stronger than them, it could drive them to retreat to other latitudes.”
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