The global environmental and public health threat of sea cage fish farming p2 of 2

carcinogenic and in April 2002 the UK Government finally banned the use of dichlorvos. Dichlorvos was also used extensively in Ireland (where a former worker with testicular cancer is now taking legal action) and Norway. The UK's Committee on Mutagenicity also published evidence showing Malachite green was mutagenic in 2000. Malachite green has been used extensively in the UK, Norway and Chile for over ten years and just last year was detected by the Veterinary Medicines Directorate in farmed salmon on sale in UK supermarkets. The same body also found PCBs in farmed salmon imported from Chile and Norway and in farmed trout from Denmark. Residues of chlordane, toxaphene, cadmium, DDT, dieldrin, oxytetracycline and dioxins have all been found in the flesh of farmed salmon. So extensive is the use of the artificial pigment canthaxanthin that escaped salmon and fish feeding near salmon cages have been found containing pink dye. The industry's response has been to call such chemicals 'vitamins', 'medicines', or 'chemotherapeutants'. Ultimately, the policy of chemotherapy is doomed to failure. The only safe way of getting off the chemical treadmill is to start ripping out the salmon cages which have spread like a cancer around our coasts. Friends of the Earth Scotland have called for a 'back to basics' approach advocating "The 3Rs": relocation, revocation and removal. With a legacy of badly located farms and contaminated sites complete removal may be a bitter pill to swallow but it is the only sensible and sustainable solution. Shifting cultivation in the sea is surely not acceptable.

Toxic salmon wastes:
The global advance of intensive salmon farming has meant that farmed fish have become agents of pollution rather than biological indicators of pollution. Salmon farms have been shown to pollute the area directly under the cages but this 'self-pollution' can also extend out to sea via the release of nutrients causing hypernutrification and eutrophication. Farms littering the coast are in effect using the marine environment as an open sewer. In enclosed areas with low flushing rates this equates to flushing your toilet only once a month. The effluent, including toxic waste containing chemicals such as dioxins and PCBs, generated by salmon farms is hardly a drop in the ocean. WWF have estimated that the 115,000 tonnes of Scottish salmon produced in 1999 equated with the phosphorus and nitrogen sewage waste equivalent of 9.4 million and 3.2 million people respectively (Scotland's population is only 5.1 million). Globally, salmon farms discharge the sewage waste equivalent of tens of millions of people. In the OSPAR Convention Area alone (including Scotland, Denmark, Norway and Ireland) nutrient discharges from aquaculture were estimated in 2000 as 36,000 tonnes of nitrogen and 6,000 tonnes of phosphorus. In the absence of discharges of human sewage, agricultural runoff or industrial effluent, aquaculture's contribution can be even more significant in isolated areas of the global economy.

Salmon farm wastes may tip the ecological balance to such an extent that algal blooms become toxic. During the past decade, there has been a worldwide increase in marine microalgae that are harmful to finfish, shellfish and humans. Mass mortalities of farmed salmon have been recorded recently in the Chiloe area of Chile, Shetland in Scotland and in Norway where millions have died in their cages. Harmful algal blooms associated with intensive aquaculture operations have been recorded in Scotland, Ireland, Norway, Japan, Finland, Hong Kong, New Zealand, Canada and Chile. Amnesic, Paralytic and Diarrhetic Shellfish Poisoning events have plagued the Scottish, Canadian, Irish, Chilean and Norwegian coasts. The international community have finally begun to tackle this issue. AQUATOXSAL, for example, is an EC-funded research project involving Chile, Argentina, France and Germany investigating the links between salmon farm wastes and toxic algal blooms. In Scotland, in response to a petition by marine toxicologist Allan Berry, the Scottish Executive have hired Professor Ted Smayda of the University of Rhode Island to assess "the impact of nutrient inputs from fish farms on the algal communities of the Scottish coastal zone". And in British Columbia the Pollution and Prevention and Remediation Branch of the BC Ministry of Environment hired consultants to "document emerging research with respect to plankton blooms and netcages". Other research has focused on the use of seaweeds to remove salmon farm waste, the addition of chemicals to 'neutralise' toxic wastes or the use of 'nappies' to collect wastes. In the final analysis, completely closed systems for the containment of contaminated wastes can be the only solution. The solution to pollution is not dilution.

Food for thought:
Salmon farming is dead in the water. Nor can the sea cage farming of other marine species such as tuna, sea bass, cod, halibut, sea bream and haddock avoid the same fatal mistakes. In the Northern hemisphere especially, we have polluted our marine environment to such an extent that we are now reaping the consequences in the biomagnification of contaminants up through our food chain. The farming of fish high up the food chain is an extremely efficient way of concentrating contaminants. In November 2000 the EC's Scientific Committee on Animal Nutrition stated that "fish meal and fish oil are the most heavily contaminated feed materials with products of European fish stocks more heavily contaminated than those from South Pacific stock by a factor of ca. eight" whilst the EC's Scientific on Food stated that fish can contain ten times higher levels of dioxins than some other foodstuffs and can represent up to 63% of the average daily exposure to dioxins. Since 'you are what you eat' it comes as no surprise to discover that farmed salmon contains high levels of PCBs and dioxins. Such is the concern that in the UK, for example, the Food Standards Agency is currently advising consumers only to eat one portion of oily fish per week. The EC have also launched a programme to test for PCBs and dioxins in a range of fish including Chilean, Norwegian, Canadian and Scottish farmed salmon. Little wonder salmon farming companies and supermarkets are reluctant to even label their fish as 'farmed' (whether they will ever label artificial colourings or chemicals used on salmon farms is another matter entirely). In the meantime consumers are being asked to "Go Wild" and steer clear of factory farmed fish.