Killer whale named Gladis leads orca gang

A vengeful killer whale named Gladis is leading gangs of orcas into battle with yachts around Gibraltar and has already sunk three boats in Europe.

It may read like something out of Moby Dick, but in this case the truth is stranger than Herman Melville's fictional tale of the white whale.

Researchers believe that a female orca called White Gladis has been hell-bent on revenge after being traumatized by a collision with a boat or being trapped in illegal fishing nets.

Gladis's attacks are now being copied by the rest of the killer whale population, which have learned how to ram vessels from their ringleader.

“That traumatized orca is the one that started this behaviour of physical contact with the boat,” said Alfredo López Fernandez, a biologist at the University of Aveiro in Portugal and representative of the Atlantic Orca working group.

This “critical moment of agony” made Gladis aggressive toward boats, and that aggressive behaviour is now being copied by other orcas, which are social animals and can learn from each other, he told Livescience.

On May 2, six of the apex predators slammed into the hull of the Bavaria 46, which was sailing in the Strait of Gibraltar, near Tangier in Morocco.

Skipper Greg Blackburn, from Leeds, was already dealing with “heavy weather” of 25-30 knot winds and a rolling swell of two to three metres when the whales made impact with his rudder with two almighty knocks.

“At that point, we were like `there's definitely something down there.'” he told 9news. “After that was when we got the first sighting of them.”

Two large orcas had carried out the first ram raids but when another four whales turned up, Blackburn knew there was going to be trouble.

“Once the main pod turned up it looked like there was a matriarch with a calf,” he said. “I thought `oh dear' when I saw them. There's not a lot you can do at that point.

“After reading reports and knowing what has been going on, I just thought we were in for a ride now.”

The skipper dropped the main sail and tried to make the boat “as boring as possible.” The whales eventually lost interest but not before causing extensive damage worth thousands of dollars. The boat was left to limp back to port.

Two days later, a pod of three orcas attacked and sank a third sailboat, piercing its rudder, on May 4, in the Strait of Gibraltar, off the coast of Spain. There was a similar attack in November last year off the coast of Portugal.

Werner Schaufelberger, the captain, said he saw the two smaller whales imitating the ramming tactic of the largest orca of the three.

“The little ones shook the rudder at the back while the big one repeatedly backed up and rammed the ship with full force from the side,” he told German publication Yacht.

“The two little orcas observed the bigger one's technique and, with a slight runup, they too slammed into the boat.”

Spanish coast guards rescued the crew of the stricken vessel but the boat sank at the port entrance of Barbate after it was towed to shore.