Back in 2017, there were reports of an invasive species:
Britain’s native salmon stocks are under threat thanks to an invasion of Pacific Ocean-dwelling pink salmon. Hundreds of pink salmon have been reported in the north east of England 10,000 miles (16,000 km) from their natural habitat. The non-native species originated in Russian commercial net fisheries before self-sustaining populations escaped to rivers in Finland, Norway, and now the UK. Britain’s native salmon are under threat from a pink rival | Daily Mail Online
By 2019 there were reports of them spreading into the north of the British Isles: Invasive Pacific pink salmon found in Scottish rivers – BBC News
And in 2021, the Environment Agency was urging anglers to report sightings of pink salmon: Anglers urged to be vigilant for invasive pink salmon – GOV.UK and Anglers on alert for invasive Pacific pink salmon – BBC News
This January, Scottish anglers were being asked to take further action:
Anglers and the general public are being asked to become ‘guardians’ of their local rivers, and report sightings of diseased, non-native and escaped farmed fish via a new suite of three apps. Locals wanted to search and destroy alien pink salmon | HeraldScotland
From January and from Alaska, here’s an interesting perspective on the ‘invasion’: They’re everywhere – Craig Medred
Vintage illustrations by Denton from Game Birds and Fishes of North America – Wikimedia Commons
And last month, the i-news reported on the latest concerns:
Scientists are braced for a record number of invasive Pacific pink salmon to arrive in Britain this summer, amid fears that the fish will become established and start breeding. There are concerns that the pinks could outcompete the already struggling Atlantic salmon for prey and territory and that they could potentially introduce new diseases and parasites to the native population. “They’re a Pacific salmon, they should be in the Pacific Ocean, but they are now the dominant species in certain northern Norwegian rivers. That’s frankly scary,” Mark Bilsby, chief executive of the Atlantic Salmon Trust told i.
Invasive pink salmon set to arrive in the UK, and could threaten Atlantic species
What’s the Difference? Atlantic vs. Pacific Salmon – YouTube