OB­STA­CLES AHEAD

Off­shore wind farms will test the sur­vival skills of salmon

Scottish Field - - CONTENTS - WORDS MICHAEL WI­GAN

Off­shore wind farms are the lat­est bar­rier for salmon re­turn­ing home

The route home for Scot­tish salmon is due for dis­rup­tion. Soon our great fish will face a for­mi­da­ble as­sem­blage of new ob­sta­cles, both at home­com­ing and at em­i­gra­tion.

The largest is the 200-plus wind tur­bine ar­ray planned for the mid­dle of the Outer Mo­ray Firth. Salmon and sea-trout from 14 rivers use this firth and there are also con­cerns for mi­grat­ing fish, in­clud­ing pro­tected eels and lam­preys. They will face con­struc­tion dis­tur­bances, wa­ter-col­umn tremors from the shud­der­ing tow­ers, and for sen­si­tive fish, the ef­fects of elec­tro-mag­netic fields. Re­mem­ber, the young salmon smolts ne­go­ti­at­ing th­ese new in­dus­trial ob­sta­cles are just six inches long.

The Scot­tish Govern­ment’s re­ac­tion to th­ese wor­ries is a prom­ise to mon­i­tor the ef­fects. Aside from the fact that mon­i­tor­ing would mea­sure ef­fects posthu­mously rather than en­sure safe pas­sage at the out­set, the is­sue for adult salmon find­ing home rivers will nei­ther be ad­dressed nor mon­i­tored. In­deed, it is dif­fi­cult to see how it would be pos­si­ble to do so.

So far the mon­i­tor­ing un­der­taken has been of the pas­sage of smolts, tagged with de­vices meant to trig­ger re­sponses from land-based acous­tic re­ceivers. How­ever, ac­cord­ing to Marine Scot­land, back­ground noise spoiled the ex­per­i­ment. Any us­able data will be avail­able later this year. So in short, the wind farm will be built re­gard­less of the ef­fect it will have on salmon and sea-trout.

In another ini­tia­tive, un­der­wa­ter tur­bines are be­ing moored on the sea-bed of the Pent­land Firth, the lo­ca­tion of fan­tas­ti­cally rich marine life. This is where the hal­ibut are so big, some over 200 ki­los, that two men have to sit on the fish for the fil­leters to cut out choice parts. The tur­bines will, in the­ory, use the fa­mously fe­ro­cious cur­rents of the firth to make ti­dal en­ergy. Where do salmon fit in? Ef­fects – you guessed right – will be mon­i­tored. In place of duty of care, re­as­sur­ances.

What if salmon and sea-trout fal­ter? If mon­i­tor­ing showed that mi­grat­ing salmon couldn’t in­ter­act with the new wave en­ergy mod­els, would the in­dus­trial plant be de­con­structed in favour of the nat­u­ral ecol­ogy? Project costs can run into bil­lions of pounds. Sal­monids, as ever, have to cir­cum­vent hu­man de­vel­op­ment. Govern­ment con­cern is purely cos­metic.

Scot­tish salmon sur­vival skills are al­ready at full stretch. De­spite the hor­rors re­cently af­flict­ing Scot­tish salmon farms – 100,000 salmon were boiled alive in sea-louse treat­ments which re­quired wa­ter too hot for the fish to with­stand – the Scot­tish Govern­ment has plans to dou­ble Scot­tish aqua­cul­ture out­put by 2030. The logic seems to be, if an in­dus­try is push­ing the edges of the en­ve­lope, boost it.

How much of the in­crease will com­prise salmon – which are now be­ing fed poul­try re­mains in a fur­ther lurch to­wards food­chain dis­tor­tion–and how much will con­sist of mus­sel-ropes and the like is un­known. What is clear is that the govern­ment is happy to at­tach its colours to the out-of­sight out-of-mind aqua­cul­ture in­dus­try as a life­line for its own cred­i­bil­ity. The cost of the pre­ma­ture cook­ing of the farmed salmon was £2.7 mil­lion.

Another 60,000 were in­ad­ver­tently killed by chem­i­cals de­signed to de­stroy amoe­bic gill dis­ease and else­where 20,000 fish were killed by mis­take. If salmon farm­ers paid the en­vi­ron­men­tal levies and fines which farm­ers on land have to they would have been bust long ago.

It’s cu­ri­ous to con­sider that when it was shown back in the 1970s that At­lantic salmon could be farmed in sea cages, it was the species’ amaz­ing adapt­abil­ity and flex­i­bil­ity which al­lowed for its suc­cess­ful in­ten­sive rear­ing. Other fish, like hal­ibut, even Pa­cific salmon, were too dif­fi­cult. The pos­si­bil­ity of mass par­a­site at­tacks were not on the radar. Vast in­dus­trial de­vel­op­ments block­ing wild salmonid mi­gra­tion routes were not en­vis­aged ei­ther.

Maybe today we are see­ing the lim­its of our salmon’s in­nate re­sis­tance be­ing tested beyond en­durance.

‘ Sal­monids, as ever, have to cir­cum­vent hu­man de­vel­op­ment’

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