BBC Wildlife Magazine - - Agenda - Jack Perks

Men­tion pink sal­mon and you ought to think of the Alaskan wilder­ness and griz­zly bears, be­cause that’s their nat­u­ral habi­tat. So when they started turn­ing up around the UK one ques­tion came to mind – how did they get here?

Pink sal­mon were in­tro­duced to rivers near the Bar­ents and White Sea ar­eas of Rus­sia be­tween the 1960s and 90s, then they slowly spread west into Fin­land and Nor­way. Now, it seems, they’ve reached Bri­tain.

This year, hun­dreds of pink sal­mon are re­ported to have swum into the River Ness, that flows out of Loch Ness into the Beauly Firth at In­ver­ness, to spawn. It fol­lows a count of 15 through­out the UK in 2015.

Sci­en­tists say they spawn in two-year cy­cles and there­fore ex­pect to see even more in 2019. They are more no­madic than na­tive At­lantic sal­mon, so it’s likely they will colonise new rivers quite rapidly. So far, they have also been caught in the River Tyne, the River Fowey in Corn­wall and the River Moy in Co Mayo on the west coast of the Repub­lic of Ire­land.

They tend to breed in the lower reaches of rivers in Au­gust, un­like At­lantic sal­mon, which spawn in the up­per reaches in the win­ter. They are much smaller, grow­ing to a max­i­mum length of 0.75m, while na­tive sal­mon can reach dou­ble that. Sci­en­tists say that pink and At­lantic sal­mon while out at sea will com­pete for the same food – shrimps, her­ring and squid – and our na­tive species is de­clin­ing through much of the Bri­tish Isles thanks to over­fish­ing, cli­mate change and dis­ease.

Chris Con­way, of the Ness Sal­mon Fish­ery Board, says that the sit­u­a­tion with the in­com­ers will be mon­i­tored. “While the risks are un­known in terms of their in­ter­ac­tion with At­lantic sal­mon and other Scot­tish fish, they are un­likely to have a pos­i­tive im­pact,” he says.

Pink sal­mon were filmed this year by the Nith District Sal­mon Fish­ery Board (NDSFB), dig­ging redds (or nests), spawn­ing and chas­ing At­lantic sal­mon from their redds. Only time will tell if they are to have a ma­jor im­pact on our na­tive fish.

Pink sal­mon – or hump­ies, as they are known – are na­tive to the Pa­cific, but have started to colonise Bri­tish rivers.

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