The company ( Balfego ) who run the tuna fishing out from L'ametlla de mar are starting boat ( catamaran ) tours from the harbour to the tuna kept offshore as a tourist attraction.
These trips are evidently free in May and a charge will be made from then onwards. You can swim with the Tuna they say. Don't know what the charge will be but should be an interesting thing to do.
Information from the tourist centre L'ametlla de mar .