The ‘num­bers game’ leads to over op­ti­mistic fore­casts

Dr Ted Need­ham: an in­de­pen­dent view

Fish Farmer - - Aqua Nor preview -

RE­CENTLY I was with a friend, shar­ing rem­i­nis­cences of the Unilever salmon farm­ing days of nearly 20 years ago, when he rather sur­prised me. ‘The old ex­cite­ment has gone,’ he claimed. ‘It is now all about num­bers.’ Cer­tainly salmon farm­ing has be­come a num­bers game. We are told - tains that we will have more than tre­bled out­put in Scot­land by the end of the be wrong. Fur­ther­more, it is an er­ror to raise peo­ple’s hopes by mak­ing them in

- blooded and to­tally at the mercy of the weather. How many smolt pro­duc­ers

busi­ness ex­pan­sion plans in Scot­land which, com­pounded with other fac­tors, will

farm­ers, at least in Scot­land. But look­ing at the last 20 years on the land it is the con­trast could not be greater, for ev­ery year the weather has a ma­jor im­pact on some or all of us.

Some thought needs to be given to mak­ing us less re­liant on the va­garies

tonnes.

The engine of farmed salmon out­put is the smolt pro­ducer and he more than any­thing else will act as the brake on out­put. This is not be­cause we wants to

It takes some four years from plan­ning a large smolt unit to achiev­ing max­i­mum out­put. Ev­ery site has its wrin­kles. Th­ese are pri­mar­ily en­vi­ron­men­tal fea years to learn to work a site prop­erly. Even­tual guar­an­teed out­put is usu­ally well be­low orig­i­nal tar­gets which seemed quite sen­si­ble when they were set.

Re­gion plan­ners are threat­en­ing to slow things down a bit and many of the priv­i­lege will be de­nied to Orkney and Shet­land un­less there are big changes in the way we raise our smolts.

One fac­tor, fresh­wa­ter cage cul­ture, could al­ter all this. The tech­niques were Isles. Rais­ing smolts in lochs is now the pri­mary means Ma­rine Har­vest em­ploys

Fresh­wa­ter cage cul­ture has much to com­mend it. The tech­nol­ogy is not quickly, though great care must be taken to pro­vide suit­able ac­cess. Fry are be­ing trans­ferred ear­lier than ever- it is now ac­cept­able to stock cages with more pre­dictable.

Fresh­wa­ter lochs are more sta­ble than burns or rivers sup­ply­ing many con- tem­per­a­tures vary less widely and pH and other wa­ter qual­ity changes strik­ing, it is ad­e­quate in most lochs tested.

Two im­por­tant prob­lems re­main; th­ese are en­vi­ron­men­tal im­pact.

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should get to­gether to tell us how we should mon­i­tor a fresh­wa­ter loch for par­a­sites to asses the risk to cage cul­ture.

salmon farm­ing.

Most of the mon­i­tor­ing has been con­ducted us­ing rain­bows in Scot­land and

in­creased phos­pho­rous im­put to the wa­ter body. This can give rise to plank­ton blooms.

It is pru­dent, nev­er­the­less, to fol­low a few guide­lines, like us­ing slowly salmon’s re­quire­ments for phos­pho­rus is sup­plied in most com­mer­cial di­ets. In ex­treme cases un­der­wa­ter pumps or pro­pel­lors could be used to pro­mote

En­vi­ron­men­tal change brought about by farm­ing salmon parr in fresh­wa­ter ex­pe­ri­ence of salmon farm­ers. Some­body should pre­pare a state­ment for stated guide­lines are fol­lowed.

In con­clu­sion, I have two fur­ther com­ments. First, John Burn of the Ma­rine -

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