The sea lochs that line Scotland’s north-west coast, famed for their natural splendour, are polluted by poisonous chemicals used by fish farms, surveys by the Scottish Government’s green watchdog have revealed.
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The sediments in nine sea lochs – all of those surveyed by the Scottish Environment Protection Agency (Sepa) – have been found to contain detectable levels of pesticides widely used to kill the sea lice that eat caged salmon.
Environmentalists, anglers and creel fishers condemn the contamination as unacceptable, and claim the chemicals could be damaging marine wildlife.
Sepa has released the results of its latest surveys of sea lochs for four pesticides: teflubenzuron, diflubenzuron, emamectin and ivermectin. These are all compounds for treating salmon infested with sea lice.
Traces of emamectin were found in sediment at all nine lochs tested in 2008 and 2009, including Loch Linnhe, Loch Ewe, Loch Nevis and Loch Fyne. Teflubenzuron was found at six lochs, and diflubenzuron at four.
Sepa pointed out that although the chemicals were known to be used at fish farms, they could also be applied by foresters and land farmers trying to combat various pests. Further investigations were required to pinpoint the exact sources of the contamination, the watchdog argued.
Sepa’s fish-farming expert, Douglas Sinclair, said: “These surveys have provided Sepa with important information on chemicals in the marine environment.
“Sepa has already instigated a programme of site visits to carry out sampling and inspections. Future monitoring programmes may be designed in a different way to provide more definitive evidence of the source of any residues.”
Sepa was targeting 40 of Scotland’s most polluting fish farms in an effort to clean them up. “As well as tackling poor performers using this action-plan approach, Sepa will undertake formal enforcement action where offences or significant environmental harm have occurred,” said Sinclair.
Others expressed more concern. “Scotland trades on its beautiful and pristine environment but the truth is we are still letting poisons contaminate our sea lochs,” said Dr Richard Dixon, director of the environmental organisation, WWF Scotland.
“International agreements quite rightly require us to eliminate discharges of toxic chemicals to the sea over the next decade. Fish farmers, farmers and the forestry industry have made progress but they all need to do more.”
Guy Linley-Adams is a solicitor who works with the Salmon and Trout Association, representing anglers. “Although Sepa suggests it cannot be sure where these residues come from, I would observe that the sampling points they have chosen are all at or near to cage salmon fish farms,” he said.
“Are we sure that these residues are having no effect on local populations of other crustaceans, such as prawns and lobsters, upon which many inshore fishermen rely for their livelihoods?”
The Scottish Salmon Producers’ Organisation, which represents the industry, argued that there was no problem. “We work within consent limits set by Sepa to ensure our unique marine environment is maintained and we are reassured that these reports confirm this is the case,” said Scott Landsburgh, the organisation’s chief executive.
Sepa stressed that the levels of contamination are mostly low, adding that although a few of the samples breached environmental standards, there was a “low risk of possible impacts”.
On Friday, the Scottish Government released new figures showing that farmed salmon production increased by seven per cent between 2009 and 2010, from 144,000 to 154,164 tonnes. That is the highest level in six years, officials said.
Farmed salmon is Scotland’s single-largest food export, with most going to the US, France, Poland, Ireland and China. Last year the industry was worth £540 million, and was the third largest in the world after Norway and Chile.