Sea Lice Ron­nie Soutar

Scot­tish sal­mon farm­ers collaborat­e to com­bat com­mon threat

Fish Farmer - - Editor’s Welcome Contents – Contact Us Meet The Te - BY RON­NIE SOUTAR

AS we move into a new decade and, with Brexit now a re­al­ity, a new era for Scot­tish sal­mon farm­ing, one fac­tor re­mains un­changed: sea lice con­tinue to be a sig­nif­i­cant threat. New chal­lenges come and, some­times, go but the Auld En­emy re­mains con­stant! We do, how­ever, have a greater ar­moury than ever on our side in this fight and 2019 saw some sig­nif­i­cant vic­to­ries.

An in­creas­ing num­ber of sites re­port hav­ing pro­duced a crop with­out ever hav­ing a treat­ment in­ter­ven­tion, ei­ther med­i­cal or phys­i­cal. This is proof pos­i­tive that pre­ven­ta­tive mea­sures and bi­o­log­i­cal con­trol re­ally are hav­ing a sig­nif­i­cant im­pact.

There is, of course, still a lot of work to be done in im­prov­ing th­ese mea­sures and, in­deed, adapt­ing them to chang­ing con­di­tions.

Some of th­ese changes we im­pose upon our­selves – in par­tic­u­lar, the move to­wards vir­tu­ally year-round smolt move­ments puts pres­sure on long-stand­ing man­age­ment areas and the fal­low pe­ri­ods which are key to break­ing the lice life­cy­cle.

It has been re­ally heart­en­ing to see the level of in­ter-com­pany co­op­er­a­tion and di­a­logue go­ing into en­sur­ing that this po­ten­tial prob­lem is not al­lowed to be­come a real is­sue.

In­for­ma­tion shar­ing has also been key in the on­go­ing devel­op­ment of phys­i­cal treat­ments. As we bring new sys­tems into play, it is vi­tally im­por­tant that we find the best pos­si­ble ways to use them on Scot­tish farms.

The in­dus­try is shar­ing ex­pe­ri­ence and mak­ing avail­able all data on best prac­tice, which is cen­tral to us mov­ing for­ward to­gether.

More than this, there is gen­uine de­sire be­tween com­pa­nies to ac­tu­ally share phys­i­cal as­sets. This is par­tic­u­larly im­por­tant as in 2019 we saw equip­ment short­age (at a na­tional level) and lo­gis­ti­cal dif­fi­cul­ties in de­ploy­ment as neg­a­tive fac­tors in lice con­trol.

With the best will in the world, and with gen­uine com­mit­ment to in­vest­ment, there is a limit to how rapidly Scot­land can gear up with new treat­ment tech­nol­ogy.

There is no doubt that, at the most se­nior level, Scot­tish farm­ing com­pa­nies recog­nise that lice are a com­mon threat, and col­lab­o­ra­tion in their con­trol far out­weighs any per­ceived com­pet­i­tive ad­van­tage in treat­ment de­vel­op­ments. In this arms race there is ab­so­lutely no doubt that lice, not other farm­ers, are the en­emy !

It goes with­out say­ing that any joint ap­proach must not com­pro­mise biose­cu­rity: it would be mad­ness to con­trol lice at the risk of spread­ing other pathogens.

The Code of Good Prac­tice has served us well in this re­spect but 2020 may be the time to re­view pro­to­cols in light of fac­tors such as in­creased move­ment of phys­i­cal as­sets be­tween farms and, in­deed, across re­gions.

We also have to keep up our fo­cus on fish wel­fare. Over the last year, fur­ther con­cerns have been raised about the neg­a­tive im­pacts of some phys­i­cal treat­ments on fish.

Some com­ments are be­hind the curve; while it seems true that un­ac­cept­able losses oc­curred dur­ing the in­tro­duc­tory phase of new tech­nolo­gies,

lessons have un­doubt­edly been learnt.

The vast ma­jor­ity of treat­ments are now car­ried out with con­fi­dence and with min­i­mal im­pact on the fish.

How­ever, gen­uine con­cerns have been raised by se­ri­ous sci­en­tists and th­ese should not be ig­nored. In par­tic­u­lar, ev­i­dence that ther­mal shock can cause suf­fer­ing has led the Nor­we­gian au­thor­i­ties to con­sider whether heat-based treat­ments are jus­ti­fi­able.

It is cru­cially im­por­tant that work on this pro­gresses and fo­cuses on the con­di­tions ex­pe­ri­enced by fish in ac­tual treat­ments, rather than in ex­per­i­men­tally ex­ag­ger­ated con­di­tions.

There also has to be a cost-ben­e­fit anal­y­sis: not fi

We en­ter this new decade with gen­uine op­ti­mism that lice con­trol is turn­ing from as­pi­ra­tion to re­al­ity”

nan­cial cost but wel­fare cost – com­par­ing any tran­sient pain with the long-term gain from the fishes’ per­spec­tive.

There are vir­tu­ally no treat­ments which have no neg­a­tive ef­fect (ask any­one who has ever had an in­jec­tion!) but the con­cept of bal­ance is well em­bed­ded in vet­eri­nary prac­tice and should be at the cen­tre of this dis­cus­sion.

Sim­i­larly, the wel­fare of cleaner fish must be front and cen­tre to their con­tin­ued de­ploy­ment. The farms which are achiev­ing best results with bi­o­log­i­cal con­trol are do­ing so largely be­cause they are fo­cus­ing on cleaner fish hus­bandry.

Again, the shar­ing of best prac­tice is key and is hap­pen­ing across the in­dus­try, in meet­ings and con­fer­ences.

Per­haps more im­por­tantly, it is hap­pen­ing in­for­mally, at ground level. Con­ver­sa­tions be­tween those di­rectly in­volved in look­ing af­ter cleaner fish, both within and be­tween com­pa­nies, are mak­ing a big dif­fer­ence to how quickly im­prove­ments are hap­pen­ing.

While we can never be com­pla­cent, and although progress can be frus­trat­ingly slow, we en­ter this new decade with gen­uine op­ti­mism that lice con­trol, in a wel­fare friendly man­ner, is turn­ing from as­pi­ra­tion to re­al­ity.

Co­op­er­a­tion is the key and the SSPO’s group of the vets, who have the in­dus­try’s stock un­der their pro­fes­sional care, re­mains a very good ex­am­ple of how we can work to­gether for the com­mon good.

Left and above: Sea lice

Right: Check­ing the sal­mon for lice

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