Within the last few days, the Atlantic Salmon Trust (AST) has published its new policy on sea lice, backed up by Professor Ken Whelan's review of the existing science on impacts of Lepeophtheirus salmonis on wild salmonids in areas where there is salmon aquaculture.

The review clearly shows that there is compelling scientific evidence that sea lice emanating from salmon farms can pose a very serious and dangerous risk to wild migratory salmonid populations.

The new policy, which is supported by science, in accordance with AST’s commitment to structure all policies in this way, represents a fresh approach to managing sea lice.

“AST’s policy advocates a completely new approach to sea lice management, because we recognise that there have been some problems with the current system of management,” said AST Chief Executive Tony Andrews. “We believe that what’s needed is what we’d term a ‘bay-by-bay’ approach. Experience has shown that the impact of salmon cages on lice loadings on wild salmon and sea trout differs from one bay/sea loch/fjord to another. This impact is dependent not only on how well salmon farmers control lice on their stock, but also on migration routes & feeding patterns of wild salmonids, and - crucially - factors such as prevailing currents and winds, the morphology of the bay/loch, weather patterns, etc. All of these factors have an impact on how sea lice larvae disperse and are transported within a sea loch, and the consequent risk to wild fish.

“These very localised factors explain why what works in one loch may not work in another. Because of this, we are calling on governments to regulate on the basis of a bay-by-bay management approach. We feel that this offers the best possible chance of giving maximum protection to all stocks of wild salmon and sea trout within salmon aquaculture areas. It is essential that more is done by the salmon farming industry and by governments to control levels of sea lice infestation on salmon farms, and to help monitor impacts on wild salmonids. We are committed to the protection of wild salmon and sea trout, and we believe that our new policy offers the best chance of success, in a world where salmon aquaculture is undoubtedly here to stay in the countries where it has become established.

“We are certainly not here to point the finger at the salmon farming industry. We recognise its economic importance for rural communities. However, there is a demonstrable need for a strong, mandatory basis for localised management. It’s also crucial that existing regulations and rules are fully enforced in salmon farming countries such as Scotland and Ireland. The sea louse is ‘the common enemy’, and we hope that a proactive collaborative approach to its management can be developed,” added Mr Andrews.

The AST policy calls for mandatory single-generation management of sea lochs/bays, and synchronised fallowing and treatment regimes, plus officially validated lice monitoring regimes, with results publicly available.