Specialists from the Hebridean Whale and Dolphin Trust were able to identify Lulu from her distinctive eye and saddle patches.
Orcas are are unique in this region and their diet primarily comprises other marine mammals. A second type of killer whales occasionally seen in these waters, but these feed primarily on fishes and seals and are far more wide-ranging.
Dr Conor Ryan, the Hebridean Whale and Dolphin Trust’s Sighting and Stranding Officer who helped identify the whale, said: “It is particularly sad to know that another one of these killer whales, unique to the British and Irish Isles, has died.
“There may be as few as eight individuals remaining in this population, which has not produced calves since studies began.”
Hebridean Whale and Dolphin Trust has been studying orca in the Hebrides using photo ID, since 1992. Lulu was last photographed by the charity from its specialised research yacht Silurian off Waternish, Isle of Skye in July 2014. During this encounter she was seen with a large male, John Coe and another female named Moneypenny.
Dr Andy Foote, an orca specialist, said: “It is very sad to lose a member of this unique group. There are lots of potential contributing factors, many of them man-made. It may also be part of a very natural process.
“It highlights the importance of the Hebridean Whale and Dolphin Trust, the Scottish Marine Animal Strandings Scheme and the members of the public that help by providing sightings, photographs and reporting strandings.”
The Scottish Marine Animal Strandings Scheme is hoping to conduct an examination of the animal in the next few days, which might shed light on the cause of death.