Farmed salmon (project)

FARMED SALMON - Risk benefit analysis of eating farmed salmon. For more details and results, see Benefit-risk assessment on farmed salmon.

Research team at KTL: Jouni Tuomisto, D.Med.Sc; Jouko Tuomisto, D.Med.Sc, PhD, prof; Marko Tainio, M.Sc; Marjo Niittynen, M.Sc; Pia Verkasalo, D.Med.Sc; Terttu Vartiainen, PhD, prof; Hannu Kiviranta, M.Sc; Juha Pekkanen, D.Med.Sc, prof

Funding: Academy of Finland; TEKES, Finland

Contact person: Jouni Tuomisto, tel. +358-17-201305

Background & objectives

In their Report “Global assessment of organic contaminants in farmed salmon,” R. A. Hites and co-workers analyzed wild and farmed salmon samples from North and South America and Europe for organic pollutants (Science, 9 Jan. 2004, p. 226). The authors conclude that, because of chemical contaminants, farmed salmon should not be eaten more often than 0.25 to 1 times per month. However, the model used does not take into account any beneficial effects of eating fish. We analyzed both risks and benefits. We also performed a value-of-information analysis to see which uncertainties were relevant for decision-making.

Results

Excess cancer mortality due to pollutants in farmed salmon was estimated at 210 cases per year [90% confidence interval (CI) 110 to 340], supporting restrictive recommendations. The number of cancer deaths that could be prevented by the restrictive recommendation on farmed salmon use was estimated at 40 deaths per year (90% CI 2 to 110). However, the recommendation would worsen the net health effect (cancer and cardiac deaths combined) by 5200 deaths per year (90% CI 34 to 19,000). It is therefore clear that if the main concern is the net health benefit, the decision-maker will not recommend restrictions. We also analyzed a decision to lower the amount of pollutants in fish feed. This lowering was estimated to save 360 deaths per year (90% CI -3200 to +4100), mainly because of possible increase in consumption of salmon.

Conclusions

The question about restricting consumption of farmed salmon appears to be nonscientific, because the outcome of the analysis was totally driven by a political variable, whether to ignore the health benefits of fish. The question about fish feed regulation was partly scientific and would benefit from further research.

Analytica-based model: File:Farmed salmon.ANA (117 K). To view the model graphically, save it to your computer, download the free Analytica-program from Lumina and open the saved model with the program. The model identifier is: URN:NBN:fi-fe20042774.