A killer whale that sparked widespread attention when it swam into a Northern Irish city almost 40 years ago is still alive and living off the west coast of Scotland, experts have found.
The whale - nicknamed " Dopey Dick" by locals after he made his way up the River Foyle into the heart of Londonderry in pursuit of salmon in 1977 - is now thought to be at least 58 and was identified when pictures of the Irish incident were compared to images taken of a pod of whales near the Isle of Skye in September 2014.
Known as Comet, the orca is part of the vulnerable west coast community whales - the UK's only known resident population of killer whales - that are tracked by experts.
Killer whale expert Andy Foote said: "When I saw the photos on Facebook, I noticed that the white eye patch of Dopey Dick sloped backwards in a really distinctive fashion.
"This is a trait we see in all the west coast community whales, but it's not that common in other killer whale populations. The photographs were all quite grainy, but it was still possible to see some of the distinctive features unique to Comet.
"I couldn't believe it - he was already a full grown male back in 1977, when I was just five-years-old."
The Hebridean Whale & Dolphin Trust has been documenting the west coast community's behaviour since 1994.
The four males and four females are not known to interact with other orca populations in the north-east Atlantic and, since studies began, have never successfully reproduced.
In January this year, one of the females, named Lulu, died after being stranded near the Isle of Tiree.
The trust said t he discovery that Dopey Dick was in fact Comet is significant to understanding the age of the west coast group.
Padraig Whooley, s ightings officer of the Irish Whale and Dolphin Group, said: "This match places Comet very much at the upper limits of the typical life expectancy of male killer whales.
"Adult males generally live to around 30 years, but with an upper range of 50 to 60 years.
"So, clearly time is not only running out for this individual whale - it is equally running out for whale biologists, who may not have much time left to gather information on this unique local population of killer whales that have made the waters of the British Isles their home."