Small yachts have been ordered to steer clear of a stretch of water off the north-west coast of Spain after at least three boats were damaged by a gang of boisterous orcas. On Tuesday, Spain’s transport ministry said yachts of less than 15 metres in length would be banned from sailing close to the coast between Cape Prioriño Grande and Estaca de Bares point in Galicia for a week. “The measure is intended to prevent new encounters with the orcas which have, over recent weeks, been responsible for various incidents in Galicia’s coastal area, mainly involving sailing vessels,” the ministry said in a statement. At the end of August, a Spanish naval yacht lost part of its rudder following an encounter with a pair of orcas, while a French boat was left with marks on its hull. Two weeks later, an 11-metre yacht en route to the UK lost steering and had to be towed into port following another orca-related incident. “The interactions with the orcas have, for the most part, affected medium-sized boats of 15 metres or less,” said the ministry. “All the encounters have taken place between two and eight nautical miles from the coast, and while the boats were travelling at between five and nine knots.” The statement said boats affected by the order could sail perpendicular to the no-go area to reach port or to head out into open water. The decision, it added, had been taken “to guarantee the safety of people and the orcas themselves”. Marine mammal experts say that while orcas are usually spotted in Galicia in September each year as the whales make their way up from the Gulf of Cádiz and follow tuna into the Bay of Biscay, the recent encounters are very rare. Bruno Díaz, a biologist at the local Bottlenose Dolphin Research Institute, said orcas were attracted to small yachts because of their size, and that the animals in question – probably “immature teenage” orcas – had probably just got a bit carried away. “We’ll never be in the mind of that individual animal, but based on experience, we think there is absolutely nothing [threatening about their behaviour],” he told the Associated Press. “We’re not their natural prey. They’re having fun – and maybe these orcas have fun causing damage.”