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Scientists claim sea lice in farms kill one third of wild salmon

EVIDENCE cited by the fish-farming industry that sea lice kills only a tiny fraction of wild salmon is seriously flawed, it has been claimed.

NET GAIN: A controversial study claims only 1% of wild salmon deaths are attributable to infested fish farms.
NET GAIN: A controversial study claims only 1% of wild salmon deaths are attributable to infested fish farms.

The scientific study published in Agricultural Sciences by a scientist of Ireland's Marine Institute, which, it has been claimed, justified the salmon fishing industry's stance that a mere 1%-2% of wild salmon deaths are due to sea lice, has been challenged in a key publication.

A recent critique by scientists from Scotland, Canada and Norway and led by Martin Krkosek of the University of Toronto's department of ecology and evolutionary biology, published in the Journal of Fish Diseases, argues that the Marine Institute's work has "fundamental errors".

Hughie Campbell Adamson, chairman of the Salmon and Trout Association Scotland (S&TAS) is now demanding that the Scottish Salmon Producers' Organisation (SSPO) retract a statement made by its chairman, Professor Phil Thomas, six months ago dismissing the impact of sea lice on wild salmon.

The new interpretation of the research claims there are "grave mistakes in measuring control and treatment groups, leading to wide inaccuracies".

The fresh examination of the original data 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 that was calculated in the original paper.

The February publication of research opened up a new chapter in the debate on the impact of the parasite on fish stocks, with recent controversial claims that sea lice thriving among farmed salmon put wild stocks at risk.

Krkosek said the purpose of the research was not to downplay other factors involved, but to highlight that parasites can and do have a large effect on the conservation of wild salmon stocks.

Mr Campbell Adamson said: "In light of what has now been clarified by Krkosek and his fellow experts in this field, one would hope that the 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 the 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."

Mr Scott Landsburgh, chief executive of the SSPO said, "We stand by our position and we, like they, are entitled to our opinion."

Krkosek's original findings - that calculated that 39% of wild salmon deaths were down to sea lice - were rigorously challenged by salmon farmers.

But Professor Christopher Todd, of the Scottish Oceans Institute at St Andrews, who was part of an international group involved in the study, defended the attack.

He said: "The salmon aquaculture industry has long placed a high priority on controlling sea lice in their captive salmon - but these results do emphasise the need for the industry to not only maintain the health of their own stocks, but also to minimise the risk of cross-infection of wild fish."

A spokesman for St Andrews University said yesterday: "The Krkosek paper is a simple matter of scientific fact, not opinion. The facts speak for themselves."

l Shetland is set for a record year of white fish landings as boats report high levels of stocks around the islands, according to Shetland Seafood Auctions.

The number of boxes sold through the local market's electronic auction system yesterday passed the 200,000 mark for the year.

It is over 30,000 up on the same week in 2012 and more than 20,000 ahead of the equivalent stage of the best previous year.

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