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 PAN International Website |
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The price of salmon
Fish farming has made salmon a readily available and affordable food, and provides jobs and investment in remote areas such as the west coast of Scotland, where both are badly needed. But are there environmental costs to pay for this revolutionary farming of the seas? And is eating farmed salmon entirely beneficial? A BBC film Warnings from the Wild: The Price of Salmon shown on 7 January 2001 tackled some of these questions head on.
Intensively farmed salmon is contaminated with organochlorine pesticide residues, including DDT.
‘Many of the fish species that go into a salmon’s diet contain contaminants known as persistent organic pollutants. They are from industrial wastes and pesticides, and even though the manufacture of the chemicals have been curtailed, residues survive in the environment ending up in the ocean and in the food chain,’ said Julian Pettifer, who researched and presented
The Price of Salmon.
According to Dr Paul Johnston, a Greenpeace scientist: ‘They are a group of widely used chemicals that are very persistent and bioaccumulative.’
The programme reported that scientists are finding surprisingly high levels of contaminants in the feed including organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs) and the flame retardants, poly-brominated diphenyl ethers (PBDEs). Testing for these pollutants is complex and expensive.
Dr Michael Easton recently carried out a pilot study (unpublished) for Canada’s David Suzuki Foundation. He analysed four types of fish feed, four farmed salmon from different sources and four wild Pacific salmon.
Dr Easton said: ‘The results were very clear. Farmed fish and the feed that they were fed appeared to have a much higher level of contamination with respect to PCBs, OC pesticides and PBDEs than did the wild fish. In fact the difference was extremely noticeable. It is a function of how the feed is made. They are concentrating the materials to produce high protein diets for the fish and ultimately the contaminants apparently get concentrated as well.’
A single portion of farmed salmon is virtually harmless, remarked Julian Pettifer: ‘But frequent consumption over time leads to an accumulation of contaminants and the concentration is exaggerated in those with low body weight. Children are considered to be vulnerable even to background levels of toxins and research is now detecting subtle effects on the population as a whole’.
Miriam Jacobs, a nutritionist and toxicologist at the University of Surrey, who has carried out a pilot study which confirmed suspected high levels of PCBs and dioxins in farmed salmon, said: ‘I am concerned about the dietary intake of small children and with infants, because their dietary intake will be far greater than it will be compared to an adult’s body weight ratio. An ongoing study in Holland monitoring background levels of PCBs in very young children and going up to school age, has found that there is a greater risk of infection and impairment of cognitive development in those children with higher intakes of PCBs.’
‘If I was considering pregnancy or breast feeding I would be concerned,’ added Miriam Jacobs. ‘All the fats bioaccumulate in breast milk. Breast milk levels of OCs, dioxins and PCBs are quite worrying. It does not mean that breastfeeding should not continue, quite the reverse. Breast-feeding is still the best for your child. But I would make every effort to make sure that my breast milk was as low as possible in these contaminants.’
The sensitivity of salmon farming was reflected in the public argument between the BBC and the FSA which followed the programme. The FSA has taken the BBC to the Broadcasting Standards Commission for what it claims was an unfair documentary. The Agency advises that the health benefits of eating moderate amounts of fish, including oily fish like salmon, as part of a healthy balanced diet, outweigh any potential risk from dioxins and PCBs.
Since the programme Ms Jacobs has done further research. She said: ‘In collaboration with the University of Antwerp I have analysed the same salmon samples, together with feed and oil samples, all collected during January 1999 for a PCBs and OCs. Preliminary data indicate that there is a relationship between the contaminant levels in the fish oils, the feed and the salmon.
The industry does not accept these allegations. But two Scottish parliamentary committees are now so concerned that they have called for an independent inquiry into the overall environmental impacts of sea cage fish farming.