MADRID, May 25 (Reuters) - Killer whales severely damaged a sailing boat off the coast of southern Spain, the local maritime rescue service said on Thursday, adding to dozens of orca attacks on vessels recorded so far this year on Spanish and Portuguese coasts.

In the early hours of Thursday, a group of orcas broke the rudder and pierced the hull after ramming into the Mustique on its way to Gibraltar, prompting its crew of four to contact Spanish authorities for help, a spokesman for the maritime rescue service said.

The service deployed a rapid-response vessel and a helicopter carrying a bilge pump to assist the 20-metre (66 feet) vessel, which was sailing under a British flag, he added. The Mustique was towed to the port of Barbate, in the province of Cadiz, for repairs.

According to the research group GTOA, which tracks populations of the Iberian orca sub-species, the incident follows at least 20 interactions this month alone in the Strait of Gibraltar between small vessels and the highly social apex predators. In 2022, there were 207 reported interactions, GTOA data showed.

Earlier in May, the sailing yacht Alboran Champagne suffered a similar impact from three orcas half a nautical mile off Barbate. The ship could not be towed as it was completely flooded and was left adrift to sink.

Guidelines issued by the Spanish Transport Ministry stipulate that whenever ships observe any alteration in the behaviour of orcas - such as sudden changes of direction or speed - they should leave the area as soon as possible and avoid further disturbance to the animals during the manoeuvres.

Every interaction between a ship and an orca must be reported to authorities, the ministry added.

Although known as killer whales, endangered orcas are part of the dolphin family. They can measure up to eight metres and weigh up to six tonnes as adults.

Reporting by David Latona; Editing by Charlie Devereux and Barbara Lewis

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