ALIEN IN­VA­SION

The furore over the ar­rival of Amer­i­can ‘pinks’ in Scot­land’s northerly rivers is a clas­sic case of much ado about noth­ing, be­lieves Michael Wi­gan

Scottish Field - - CONTENTS -

The march of the Amer­i­can 'pink' salmon in Scot­land's rivers is cre­at­ing a bit of a stir amongst an­glers

‘News­pa­pers have raised the spec­tre of in­ter­breed­ing’

Noth­ing stirs imag­i­na­tions more than alien in­va­sions, so the ap­pear­ance in sev­eral Scot­tish rivers – the Deveron, Spey, Wick, Hal­ladale, Helms­dale, Thurso and oth­ers – of Amer­i­can ‘pinks’ has fired up many an­glers.

They are salmon, but they hail from North Amer­ica, home to eleven species of salmon broadly called ‘Pa­cific’. There they mi­grate into 1,300 lakes and rivers and form the prin­ci­pal food sup­ply and pro­tein en­rich­ment for bene­fac­tors rang­ing from griz­zly bears to forest­land soils. Bet­ter-known types are chi­nooks, coho and sock­eye.

Pinks, also called hump­backs, are the most nu­mer­ous. I once walked onto a stream in Bri­tish Columbia chock-full of spawn­ing pinks, it was so packed that wa­ter was spilt onto the bank. I felt I had in­truded on a primeval scene.

The pinks now stray­ing into Scot­tish rivers de­rive from pop­u­la­tions in­tro­duced in Nor­way and arc­tic Rus­sia in the 1950s, sup­posed to nat­u­ralise and be­come a com­mer­cial fish­ery. They never did.

An­glers who thrill at the thought they can now openly kill a salmon and eat it may be dis­ap­pointed. Pinks are not fa­mous eat­ing.

News­pa­pers have raised the spec­tre of in­ter­breed­ing with our own At­lantic su­per­star. It has never oc­curred, even in lab­o­ra­tory ex­per­i­ments. At an aes­thetic level, why should it? The pink has small scales, a thin mouth with a black tongue, teeth which pro­trude more as spawn­ing ap­proaches, and weighs about 4 pounds. No sel­f­re­spect­ing At­lantic hen salmon would en­ter­tain a hump-backed, toothy freak dressed in lurid ma­genta, surely?

What makes in­ter­breed­ing even less likely is ear­lier spawn­ing, per­formed only in the lower reaches of rivers. Then young fry swim from natal grav­els and float straight to sea. They barely oc­cupy the river habi­tat, like a nest­ing bird fledg­ing al­most straight away.

Pacifics in Scot­land are silly sea­son sto­ries, true enough fac­tu­ally but prob­a­bly with­out

‘By Au­gust a mere 60 salmon (tar­get 750) had been tagged’

bi­o­log­i­cal sig­nif­i­cance. Per­haps more silly, but with sig­nif­i­cance, is the Scot­tish gov­ern­ment’s acous­tic track­ing ini­tia­tive. Salmon caught at a north coast net-sta­tion are tagged, and then logged by acous­tic re­ceivers when they en­ter rivers.

With apolo­gies for the sud­den­ness of the project, Ma­rine Scot­land asked some 70 rivers to par­tic­i­pate in June. The net sta­tion at Ar­madale in Suther­land was cho­sen, de­spite its mod­est catch his­tory com­pared to nearby Strathy Point, de­ploy­ing a sin­gle bag-net. Em­ploy­ees of river boards (the bod­ies gov­ern­ment tried un­suc­cess­fully to abol­ish in its wild fish­eries leg­is­la­tion) helped de­ploy and fix the re­ceivers, billing the gov­ern­ment for time and ef­fort.

The tags ar­rived tardily, in July. Crit­i­cisms by lo­cal nets­men that the whole project was too late looked close to the bone. By Au­gust ninth winds had been un­favourable and a mere 60 salmon (tar­get 750) had been tagged. No tagged salmon is known to have been re­cov­ered by an­glers, who were to re­ceive re­wards. It looks in­con­ceiv­able that the pro­gramme, so de­layed, can pro­duce mean­ing­ful re­sults, de­spite cost­ing half a mil­lion pounds.

The re­search was de­signed to re­veal the spawn­ing rivers of salmon ar­riv­ing on the north coast. Eighty years ago W.J.M. Men­zies tagged and tracked salmon cir­cuit­ing Scot­land seek­ing their natal rivers. In the 1940s and the 1950s more work was done. We al­ready know that these north coastal salmon can ap­pear in rivers al­most ev­ery­where on coasts both east and west.

Salmon tagged in Ar­gyll were re­cap­tured on the op­po­site coast in the Tay. North coast tagged salmon showed up south of Glas­gow on the Ayr, and in Lewis, even in Ire­land. Need­less to say, they were found too in most rivers be­tween these dis­tant points.

Read­ing the old-time lit­er­a­ture would have been sub­stan­tially cheaper than set­ting up ex­pen­sive re­search pro­grammes. Less egg would adorn fewer faces. The an­swers, like the pro­gramme about aqua­cul­ture’s sea-lice ef­fects on wild salmon, are al­ready known. But maybe now gov­ern­ment is get­ting in­ured to em­bar­rass­ment.

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