A killer whale found dead on a Scottish beach probably became tangled in fishing gear and drowned, experts say.

The orca, known to researchers as Lulu, was found dead on the island of Tiree in the Inner Hebrides on January 3.

Investigators from the Scottish Marine Animal Stranding Scheme (SMASS) believe Lulu drowned after becoming entangled in ropes which were probably connected to fishing gear.

They believe there may now be as few as eight killer whales left in UK waters.

It is the recorded incident of its kind in Scotland, but other species of whale have died in similar circumstances. SMASS described Lulu's death as "tragic" but said it has allowed them to learn more about Britain's native orca population.

Investigators reported: "We found convincing evidence that Lulu had become chronically entangled and this was the most likely cause of her death. There were deep, granulating wounds around the tailstock and tell-tale twin linear abrasions on the underside of the tail fluke.

"These are consistent with a rope wrapping around the tail and trailing behind the animal, probably still attached to something at the other end.

"This would have made normal swimming very difficult, and we suspect the animal had been entangled for several days. "She hadnt fed recently but had swallowed a large amount of seawater, most likely as she eventually succumbed to the entanglement and drowned.

"There were no ropes or gear left on the carcase - were assuming all this from the lesions we found on her body so we dont know if this was due to active fishing gear, abandoned or ghost gear, or other marine debris.

"The lesions are very similar however to those we see from creel rope entanglement in baleen whales.

"This is the first killer whale we have seen which has been entangled, although we have had an increase in entanglement incidence in other large cetaceans over the past year."