A coalition of Scottish environmental groups under the banner of the Scottish Wildlife and Countryside Link (SWCL) has produced a review of the environmental impacts of marine salmon fishing in Scotland, that calls for a number of changes to current practices(1). The report, Leaping in the Dark written by aquatic environmentalist Alison Ross, highlights key areas for improvement, identifying a need for:
national strategic guidance;
democratic and environmentally sensitive planning control;
effective regulation and monitoring of the salmon farming industry's operations.
Chemicals-cause for concern
The use of chemicals to control sea lice parasites
which attack farmed salmon is one area of particular concern (see PN34 p3). The
cost of sea lice to the industry in terms of fish losses and treatments, has
been estimated at £22 million per year. The extent of the problem sea lice
present to the salmon farming industry is also indicated by the level of
research effort that has been focused on developing effective treatment methods.
The use of the organophosphate (OP) dichlorvos was strongly opposed by
environmentalists (see PN6 pp4-7), but was the only chemical licensed for sea
lice treatment until hydrogen peroxide came into use in 1993. Ivermectin has
been in illegal use in Scotland since 1991, but fresh controversy was raised
when it was granted discharge consent in 1996. The OP azamethiphos also gained
market authorisation in 1996. Further research by pharmaceutical companies is
ongoing to bring other treatments onto the market. In addition, various types of
physical lice removal have been explored and a major research programme has been
in progress since the late 1980s to develop a sea lice vaccine.
In the last few months, the first certificated organic salmon
in Europe have been harvested off the Western coast of Ireland(2). The fast
flowing tides and exposed conditions, near Clare Island off County Mayo, ensure
that there are very few lice and disease problems.
Recommendations
In terms of chemical control, the SWCL report
recommends:
The industry should place more emphasis
on the prevention of sea lice and disease problems through improved
husbandry practices, particularly with regard to stocking densities.
In preference to chemical control, the
industry should adopt, and the Scottish Environmental Protection Agency (SEPA)
should promote, the use of biological controls, such as the cleaner fish,
and the development of other non-chemical use.
SEPA should adopt a clear presumption
against the continued use and further development of toxic chemicals with
its guidance on sustainable development.