Continued invasions in Mediterranean waters of blue crab, a native of the Atlantic coast of North America, are creating trouble for fishermen and shellfish stocks in Italy, Albania, and other countries, industry and government officials report. The crusty invaders are assumed to arrive in the ballast water of shipping vessels, which is collected along western North Atlantic coasts and discharged often untreated into the Mediterranean. The crabs have no natural predators here and adapt quickly, voraciously consuming local crabs and other shellfish to the point of endangering the ecosystem and the local economies that depend on Mediterranean natural resources. In the western Atlantic, blue crabs are a favorite food of sharks, rays, and other predators, but thrive unchallenged in parts of the Mediterranean.
One solution that has been proposed – eat as many as you can catch – has resulted in about 326 tonnes of harvested crabs in Veneto so far this year but with little observable dent in their population growth. One industry official complained that fighting with a cookbook such a widespread emergency that was causing thousands of fishermen to struggle was wrong. We need a serious programme to control the blue crab in our waters, he said, adding that it was a mere illusion to hope to eradicate this species in the short to medium term. According to the fishers’ association Fedagripesca-Confcooperative, the crabs had already caused economic damage of about EUR100m in Italy as a whole and have devoured up to 90% of young clams in the Po delta, severely threatening future production.