Salmon & Trout Association (Scotland) demands that Scottish Government stops prevaricating and orders an immediate cull of farmed salmon in the affected areas as done in Norway

As the damage being caused to wild salmon and sea trout in Scotland continues, the latest aggregated sea lice data, published by the Scottish Salmon Producers Organisation (SSPO), shows that in the third quarter of 2013 sea lice numbers on farmed salmon were massively out of control in the north-west Highlands.

The latest SSPO quarterly sea lice report (for July to September) reveals that average lice numbers during September on farms between Kinlochbervie in the north and the Applecross peninsula in the south were between nine and 12 times over the industry’s own threshold.

The Salmon & Trout Association (Scotland) (S&TA(S)) believes that these numbers warrant an immediate cull of all the salmon on the affected farms, similar to that recently instigated by Norwegian authorities in the Vikna district of Nord Trondelag, in order to protect migrating wild salmon and sea trout in the spring of 2014.

The SSPO report confirms “out of control” lice numbers in the following areas:

  • ‘Inchard to Kirkaig North’ – eight salmon farms, all run by Loch Duart Limited, the self-styled “sustainable salmon company”. Over the industry’s own lice threshold for all three months and in September the monthly lice count on farms in this area was over nine times the threshold, despite 13 separate lice treatments carried out at these four farms in this period.
  • ‘Kennart to Gruinard’ – seven farms operated by two companies, Wester Ross Fisheries Limited and Scottish Sea Farms Limited. Over the threshold for all three months. In September the monthly lice count on farms in this area was over nine times the threshold.
  • ‘Badachro to Applecross’ – four fish farms operated by Marine Harvest (Scotland) Limited and the Scottish Salmon Company. In September the average lice count on farms in this area was 12 times the industry’s own threshold.

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

“We have been warning the Government for years that the headlong rush for expansion, combined with increased sea lice resistance to the cocktail of drugs used to control them, would end in disaster.

“This report confirms that, in the north-west, we have now reached that point. The numbers are truly shocking and by any definition the salmon farmers in these areas have lost all control. There can now be no excuse for Scottish Government Ministers to continue to prevaricate. Ministers must now order an immediate cull of all the fish in the affected farms – the kind of decisive action taken by the Norwegian authorities two months ago when they were faced with a similar problem – and the fallowing of these farms until such time as a proven solution is identified.

Failure to do so will amount to undeniable confirmation that Ministers are simply not prepared to provide any protection whatsoever for wild salmon and sea trout”.

Guy Linley-Adams, Solicitor to the S&TA(S) Aquaculture Campaign, said:

“In light of these appalling figures, we challenge Richard Lochhead, the Cabinet Secretary for Rural Affairs and the Environment, and Paul Wheelhouse, the Minister for the Environment, to point us in the direction of a single scientist from their own Marine Scotland Science department who is prepared to stand up and say that such numbers do not present a devastating problem for wild fish. The situation is now so serious that we need a response direct from a Minister.

“The system of light touch regulation of salmon farms has failed. Ministers must now introduce without delay statutory controls on on-farm sea lice numbers to protect juvenile wild fish from lethal infestations.”

Mr Linley-Adams added:

“No-one should be fooled the industry’s recent re-gurgitated announcement that wrasse will solve the sea lice issue on farms. Wrasse have already been employed in parts of the north-west and clearly they have not worked.”

Why are sea lice on fish-farms such a threat to wild salmonids?

The negative impact of sea lice, produced in huge numbers by fish farms, on wild salmonids (salmon and sea trout) is widely accepted by fisheries scientists including the Scottish Government’s own Marine Scotland Science (see Note 3).

Most recently, a new paper published in 2013 by a group of fisheries experts from Norway, Canada and Scotland re-analyses data from various Irish studies and shows that the impact of sea lice on wild salmon causes a very high loss (34%) of those returning to Irish rivers (see Note 4). 

Most importantly, there is clear evidence that both wild salmon and sea trout are in decline in Scotland’s ‘aquaculture zone’, whereas, generally, populations have stabilized on the east and north coasts where there is no fish-farming (see Note 5).



1) Just what is the problem with sea lice? Adult wild salmon are perfectly adapted to coping with a few sea lice. Background levels of these parasites occur naturally in the sea. However the advent of salmon farming, particularly in fjordic sea lochs, has led to a fundamental change in the density and occurrence of sea lice in parts of the coastal waters of the west Highlands and Islands. Even one or two mature female sea lice per fish within a set of cages housing hundreds of thousands of farmed salmon amounts to a rampant breeding reservoir  pumping literally billions of mobile juvenile sea lice out into the local marine environment. The consequences when wild salmon and sea trout smolts, the metamorphosing fragile skin of which is not adapted to cope with more than the odd louse, migrate from local rivers into this “sea lice soup” are devastating.

A burden in excess of 13 pre-adult sea lice is known to compromise severely the survival of juvenile migratory salmonids. Lice feed by grazing on the surface of the fish and eating the mucous and skin. Large numbers of lice soon cause the loss of fins, severe scarring, secondary infections and, in time, death. Quite literally, the fish are eaten alive. Badly infested salmon smolts disappear out to sea, never to be seen again. In contrast afflicted sea trout smolts remain within the locality and they, together with the impact of the deadly burdens they carry, are more easily monitored through sweep net operations.

2) The SSPO report giving aggregated sea lice data from fish farms from July to September 2013 is available for download via this link:

3) Marine Scotland Science (2013) Summary of information relating to impacts of sea lice from fish farms on Scottish sea trout and salmon – 4th April 2013 – see Note that Marine Scotland Science acknowledges that compliance with the thresholds within the Code of Good Practice is not necessarily sufficient to ensure that juvenile sea lice emanating from the fish farms do not damage wild fish.

See also S&TA (2013) Recent research and findings on the impact of salmon aquaculture on wild salmonids – see

4) M Krkosek, C W Revie, B Finstad and C D Todd (2013) Comment on Jackson et al. "Impact of Lepeophtheirus salmonis infestations on migrating Atlantic salmon, Salmo salar L., smolts at eight locations in Ireland with an analysis of lice-induced marine mortality" – Journal of Fish Diseases.