l'Ametlla de Mar in the news for the wrong reasons.
I've wondered for a long time what the big cages in the sea off l'Ametlla were for. It seems that they catch wild tuna and then fatten them up in the cages before sending the carcasses off to Japan.
Blue-fin tuna is now close to extinction.
http://news.bbc.co.uk/2/hi/science/nature/8575721.stm
http://news.bbc.co.uk/2/hi/europe/8577538.stm
Also realised from this that the 'playa d'Almadrava' by Tres Calas is named after the annual slaughter where the tuna were herded into the bay.

It seems that the Tuna are caught wild, then fattened in the cages out there, Mussels are usually grown on ropes.

Not sure there is any connection to dead fish in L'Ampolla, I have fished for Palometa there at the harbour entance as the fishermen clean out their catches and throw out the undesized fish. Some boats near here got caught for undersized catches recently, but there is still plenty blatantly on sale. One of the new Aquatium/Fishmongers in Tortosa recently sold a friend 4 different bags, all illegal/undersized/protected species. One night fishing near L'Ampolla last year, you could clearly hear a banging that was Poachers using an illegal method to drive fish into nightime nets...... all Forestals safely in bar/bed, they carried on safely.