"The study, led by Prof Eric Verspoor, found four genetically, ecologically and visually distinctive species that have evolved in the loch over the last 10,000 years.
One of the species, a "Profundal Benthivore", has not as yet been reported to occur in any other loch in the brown trout's native range."
https://www.bbc.com/news/uk-scotland-south-scotland-46411233