Is Farmed Salmon Safe to Eat?

Jouni Tuomisto and his team used Analytica to create a more comprehensive risk analysis: It addressed both the risks from pollutants in farmed salmon and the health benefits of salmon relative to beef and other animal proteins — notably those due to Omega-3 fatty acids. They expressed uncertainties about key parameters as probability distributions to enable explicit analysis of the sources and sizes of uncertainties. Results: The model estimated the excess cancer mortality due to pollutants in farmed salmon as 210 deaths per year in Western Europe (110 to 340 deaths with a 90% confidence interval [CI90]). It estimates that the restricted consumption of farmed salmon recommended by Hites et al. would prevent an estimated 40 deaths per year (2 to 110 as CI90). However, this recommendation would actually worsen the net health effect due to greater consumption of beef instead of salmon, increasing cancer and cardiac mortality by 5,200 deaths per year (34 to 19,000 as CI90). They concluded that, if the main concern is net health benefits, we should not restrict consumption of farmed salmon. KTL also analyzed the effect of reducing pollutant levels in fish feed. They estimate that this policy would save 360 lives per year , mainly because of a likely increase in consumption of salmon. The wide range (-3200 to +4100, CI90) results from scientific uncertainties, and especially uncertainty about how much this policy would affect levels of consumption. This level of uncertainty implies a high value for further research. They published their results in an article in Science, and offer the Analytica model available for free download for review.
KTL extends Analytica’s influence diagram notation as a Pyrkilo diagram: This adds node types to display argument structure, key issues and conclusions.