Sir, - Your environmental correspondent, Kevin O'Sullivan, recently documented the licensing and use of pesticides for usage in finfish firming, mainly to combat infestations of sea lice on caged salmon. In 1989. the organophos phorus insecticide, dichlorvos, Nuvan, was placed by the EC on its red list of most dangerous substances for use in water yet the Department of the Marine granted a licence for the compound for use on fish farms.
When the lice became resistant to Nuvan, salmon farmers switched to Ivermectin, a commonly used anti parasitic agricultural drug. Because no aquatic testing had been carried out with this compound, the manufacturers specifically and publicly recommended in 1992 that it not be used in salmon farming as it retains an aquatic ability to kill organisms for a long time. The compound was not licensed for aquatic use by the Department of the Marine yet it was openly and widely used throughout the salmon farming industry. Last year, without the usual format of scientifically acceptable field trials, the compound was granted a licence by the Department.
As Ivermectin is failing to control the proliferation of lice populations, the artificial pyrethrins are being used. These highly potent chemicals - the contents of one cypermethrin based sheep dip can wipe out all invertebrate life from 15 miles of river - post few dangers to the human handlers but are hundreds of times more toxic to wildlife. They are banned elsewhere in the world but the Department of the Marine is again turning blind eye and deaf ear to legitimate clamours that a precautionary principle should apply before allowing release of highly toxic compounds. on a routine and prophylactic basis, into our waterways.
This Department has the necessary wherewithal to carry out all necessary trials on these compounds before allowing them generalised usage; it also has the statutory obligation to protect the wild salmon and sea trout which become rarer by the day in the vicinities of the salmon farms. Shellfish farmers, fishermen, anglers and wildlife enthusiasts have equally legitimate rights to use our waters and to insist that the wild creatures inhabiting these areas are not silently and indiscriminately destroyed by pesticides.
We now have scientific proof that some bird species have decreased by 87 per cent, others, like the lapwing, by 70 per cent, as a direct result of farming pesticides used on land. The suspiciously empty and eerily quiet seas surrounding many salmon farms indicate that a similar submarine carnage has long been in progress. Surely it is time our authorities adopted an intellectual independence and carried out their own separate investigations on these compounds rather than rubber stamp totally unsupported claims from the users of these toxins that they are "totally harmless to the environment". - Yours, etc.,
Maida Vale,
London, W9.