SEPA on the hook over Slice pollution

ForAgyll.com asserts that the Scottish Environment Protection Agency (SEPA) has case to answer. Information obtained under Freedom of Information by the Salmon and Trout Association Scotland (S&TAS) as FoI reveals breaches of Environmental Quality Standards at nearly one in five fish farms.

Slice – emamectin benzoate – is routinely used against sea-lice in caged fish, but it is toxic to lobster, crabs and prawns. Data from 146 fish-farms that used Slice between January 2011 and September 2012 were obtained by the S&TAS. At 28 of those farms (19.1%), Environmental Quality Standards were breached.

The results are broadly in line with an earlier study by the S&TAS based on data obtained under FoI and covering 2005 to 2010. At that time, the Environment Minister responsible, Stewart Stevenson MSP, said that if Environmental Quality Standards for sea louse chemicals were breached, SEPA would take steps to rectify the situation. These would include a limit on the further release of these substances until residue levels reduced to ‘below identified safe levels.’

The S&TAS has not seen any sign of SEPA varying the conditions of any fish-farm licence to reduce chemical residues. Marine Harvest is the biggest fish farm operator in Scotland and has been short-listed for the Stewardship Award in the Crown Estate sponsored Marine Aquaculture Awards 2013 – yet 15 of the 28 fish-farms with samples in breach of Environmental Quality Standards for Slice are operated by Marine Harvest (Scotland) Limited.

ForArgyll points to what it calls ‘the Catch 22 of open cage intensive aquaculture.’ Heavy sea lice infestation is common in the dense populations of caged fish, and also presents a serious threat to wild salmon and trout fisheries. Free swimming sea lice around the cages – often in waters through which migrating salmonids must travel – are fatal to the vulnerable juveniles on which the futures of the fisheries depend.

But if the cage populations are drenched with Slice to keep the sea lice under control, though wild fish may benefit in the short term, sea bed residues of these chemicals threaten wild crustaceans, which are particularly susceptible to Slice. Lobster, crab and creel fishermen operating in the loch systems are acutely aware of this, seeing their catches dwindle where salmon farms are using emamectin benzoate.

The only real solution is to use closed containment salmon farming. Meanwhile, SEPA has a serious case to answer for its neglect of the responsibilities on which its existence is assumed to rest.