Blue crab invasion hits the Costa Blanca

THE AMERICAN blue crab is considered a delicacy in the United States and is an important part of the economies of Maryland, New Jersey, Louisiana, North Carolina and the Chesapeake Bay area.

This crab, which can grow to 23 cms and weigh up to half a kilo, has very strong pincers and jaws that can destroy nets; it is also extremely aggressive and has a big appetite. It was first spotted in Spain in the Ebro Delta in 2012, it rapidly established itself and spread very quickly along the Catalan coastline.

Now they have reached the Costa Blanca, and are spreading like wildfire, crabs have been seen in Guardamar, Torrevieja and Santa Pola, as well as in the Barranco de Ovejas watercourse in Alicante and even the Pego marshes. It is thought that they arrived in the Mediterranean from the Gulf of Mexico in shipping ballast tanks, although larvae could have escaped from Turkish coasts, where an attempt was made to farm them.

Local artisanal fishermen in Guardamar and Santa Pola are very worried indeed, as these crabs are devouring local prawns and cuttlefish and breaking their skimpy nets.

Marine investigators from Alicante University have warned the crabs are expanding very fast indeed, they are very fertile and have a long life; the warm seas of this area allow them to reach maturity quicker. The only natural predator they seem to have, are octopuses.

Carmen Barbará, head of Alicante University’s marine science department, suggests that the best way to keep their numbers down is to allow their commercial fishing. This is currently allowed in Ebro Delta, where they are popular with local restaurants.

The problem in this area would be that stronger nets would have to be used, and this could negatively affect other species. In the US, they are fished using crab pots as well as simple techniques using hand lines and dip nets.

The blue crab can be found in the sea in the summer months, where the females lay their eggs, at the beginning of winter the females and young crabs migrate towards fresh water sources including rivers, irrigation channels and the lagoons of El Hondo in Elche. They can also be spotted in the salt lakes of Santa Pola.

If commercial fishing is eventually authorised, it could boost the local economy. The meat from their claws is very tasty, and similar to lobster.