This summer a number of reports of killer whales (or Orcas) attacking leisure vessels in the Strait of Gibraltar and around the Portuguese coast began emerging. This species of dolphin is typical in this region during the summer months leading into September, however, reports of attacks are rare. Nonetheless, several reports of “deliberate attacks” have been described recently.
Scientists have proposed a number of causes for the interactions such as confusion, defensive behaviours or possibly a newly learned behaviour. These large animals are known to hunt tuna in these areas, and in recent times they have been noted as stealing tuna caught by Spanish or Portuguese fisherman. Obviously, this also results in an increase in interactions between these animals and humans. Dr Eric Shaw has worked with the dolphins in the Strait of Gibraltar for a number of years has proposed a potential explanation for these attacks:
“From what I’ve heard people describe or read in various articles, I think this is protective behaviour that is taking place. The first report was from the coast of Portugal and in the Bay of Biscay. These areas are well known for Tuna following the fish along the continental shelf at this time of year. In the marine world, we know food follows food, and fingerlings of smaller species are moving into deeper water where they become prey to larger species, onwards and upwards to the largest within the ocean.