Sailing boats over 50 feet long have been banned from a stretch of Spain's northern coastline where several vessels have been attacked by killer whales.
Government officials have admitted the measure could be applied to other areas where the animals live and hunt and have been involved in recent incidents, including the Straits of Gibraltar.
The Directorate General of the Merchant Marine (DGMM), part of Spain's Ministry of Transport, has also announced a plane normally used in firefighting will be deployed to identify the killer whales thought to be responsible and alert seafarers in the area.
The sailing ban applies to the coastline off the north-west region of Galicia, between Cape Priorino Grande near the city of Ferrol and Spain's northernmost point Punta de Estaca de Bares. It is due to last a week.
The plane is expected to focus on the off-limits area.
A spokesman for the DGMM described the move as 'proportionate and objective'.
He added: 'The measure is designed to prevent new episodes involving killer whales which have caused several incidents in Galicia's coastal area in the past few weeks involving mainly sailing boats.
'The sailing boats affected by this decision can navigate perpendicular to the off-limits area to reach the coast or head out to sea.'
The recent spate of attacks on boats in Spanish and Portuguese waters by killer whales, which have left at least one crewman injured, have baffled scientists.
Marine life experts have described them as 'unheard of.' Biologists have reportedly compiled a list of around 40 'interactions', 29 of them in Galicia, since one on July 20 between Gibraltar and Cape Trafalgar.
In a recent incident Halcyon Yachts were taking a 36ft vessel to the UK from the Galician city of La Coruna when a killer whale rammed it at least 15 times.
The vessel lost steering and had to be towed back to port because of the attack.
A yacht named as Gautier was attacked on Tuesday and had to be towed back to the town of Muros south of La Coruna - outside of the off-limits area - after its rudder was damaged.
Marine lift experts say they believe two young killer whales in one of three groups of 13 animals located in Galician waters could be behind the attacks.
The theory they are reacting to a previous attack by a seafarer has not been ruled out and scientists have speculated they could be linked to a decrease in the number of boats at sea during the coronavirus lockdown which has increased curiosity among the young killer whales.
But most experts have concluded the animals see their attacks on the rudders they have targeted as a game and could be using them to hone their hunting instincts.
Around seven boats have had to be towed back to port since the incidents began because of damage caused to their rudders.
Bruno Diaz, a marine biologist based in Pontevedra in Galicia, told a local Spanish paper earlier this month: 'It's possible the incidents have taken place because young animals in a group are practici