Salmon and Trout Association (Scotland) demands that the Scottish Salmon Producers’ Organisation (SSPO) retract its February statement dismissing the impact of sea lice on wild salmon. New scientific paper shows that SSPO relied on a study that was fundamentally flawed.

The Salmon & Trout Association (Scotland) (S&TA(S)) is calling on the Scottish Salmon Producers’ Organisation (SSPO) to retract its triumphant announcement earlier this year that “the average mortality in wild salmon due to sea lice is tiny, less than 1%”. The scientific study in Ireland, which SSPO used to justify its controversial position, has now been exposed as fundamentally flawed.

In January Dr Dave Jackson of the Marine Institute in Ireland had a paper published in the Journal of Fish Diseases which concluded that there was a negligible risk (1%) to migrating salmon from sea lice. The paper apparently examined 350,000 fish, released into eight different rivers in 28 separate experiments over nine years.
This paper was seized on by SSPO as a silver bullet dismissing once and for all that sea lice (emanating from salmon farms) have any meaningful impact on wild salmon numbers. SSPO issued a news release on February 1st 2013 ( entitled “Sea lice threat to wild salmon ‘no basis in scientific fact’, finds new study” in which Professor Phil Thomas, Chairman of SSPO, trumpeted: “I welcome the findings which are rigorous, definitive and unequivocal…..”

Last week the very same Journal of Fish Diseases published another paper by Krkošek et al – international experts on sea lice and methodology (from Scotland, Norway and Canada) – demolishing the Jackson paper and in particular pointing out fundamental errors in Jackson’s methodology:

  • Data differences from year to year were not treated appropriately.
  • Averages regarding the survival of fish were used incorrectly.
  • Grave mistakes in measuring control and treatment groups, leading to wide inaccuracies.

The new paper re-analyses the original data and shows that the impact of sea lice on wild salmon causes a far higher loss (34%) of those returning to Irish rivers than the 1% loss deduced in the Jackson paper.

Hughie Campbell Adamson, Chairman of S&TA(S), said:

“In light of what has now been clarified by Krkošek and his fellow experts in this field, one would hope that SSPO, if it is to retain any credibility as the representative trade body for the salmon farming industry in Scotland, will have the integrity to withdraw formally the press release it issued in February in which the SSPO Chairman Professor Phil Thomas made his inflammatory and ill-considered statement. It is now clear that the paper SSPO and Professor Thomas relied on to justify their position is simply a travesty and indeed, given the flaws which have now been exposed, should never have been published”.

Guy Linley-Adams, Solicitor to the S&TA Aquaculture Campaign, commented:

“It is now time for SSPO to stop hiding behind a smokescreen of dubious science and acknowledge that sea lice spreading out from salmon farms can have a devastating impact on the marine survival of both salmon and sea trout. In the short term, those farms sited in the mouths of salmonid river systems must be relocated away. The only long-term solution is, of course, for all salmon farm production to move to closed containment units, thus creating a biological barrier to prevent the transfer of parasites from farmed fish to wild fish”.