Several thousand pink salmon were caught in one net in connection with the extraction of the blacklisted fish. Too many Pink Salmon in the oceans and rivers threaten other species of salmon in Norway.

“Dramatic”, says researcher Henrik H. Berntsen. The Norwegian Environment Agency has launched a major offensive to get rid of the invasive species. But, despite more fishing, there appear to be ever more humpback salmon arriving in Norwegian rivers. Currently, around 70,000 pink salmon have been caught in Norwegian watercourses this year.

'Unprecedented numbers' of pink salmon were seen in 2017 and the fish have been spotted again this year.

“Our results suggest that warming is both increasing freshwater habitat and improving early marine survival of pink salmon in the northern Bering Sea,” said Ed Farley, NOAA Fisheries biologist at the Alaska Fisheries Science Center, who led the study.

Pink salmon are native to the Pacific Ocean. From stocking programs in Russia in the 1960s they have spread to Northern Europe, and in 2017 male and female pink salmon were spotted in the River Ness in the Highlands of Scotland. And now, two years later, camera images suggest that their spawn has returned.

Two pink salmon have been found near Fort Good Hope, N.W.T., 260 kilometres farther up the Mackenzie River than ever reported.