Canadian farmed salmon lower in mercury than wild fish

A study out today concludes that Canadian farmed salmon contains less mercury than wild salmon caught in nearby waters. Published in Environmental Toxicology and Chemistry, the study actually finds that wild fish has three times the amount of mercury. Levels in farmed and wild fish were below those that trigger health warnings.

More findings, from a press release on the salmon study:

* Compared to other foodstuffs, total mercury was found to be slightly higher in wild or farmed salmon than in chicken, beef or pork but comparable to fruit, vegetables, honey and eggs.

* Levels of other trace elements were lower in salmon than in other foodstuffs, and average dietary intake of mercury and trace metals from salmon remains low (0.05%–32%) compared to meat, poultry, fruit, and vegetables (68%–99%).

* Salmon also showed a moderate surplus of selenium, which is beneficial because of its ability to detoxify and counteract mercury toxicity.

We've reported opposite sorts of results in the past when it comes to PCBs and farmed vs. wild fish.

Four years ago, we covered a study showing that farmed fish from Europe and the Americas were higher in PCBs and other industrial pollutants than wild fish. The research suggested limiting farmed-fish consumption to once a month.

We also looked specifically at fish caught in Puget Sound and found elevated PCB levels there as well, putting them at a level at which people should only eat the fish three to four times a month (bigger chinook or king salmon had higher levels than smaller coho).

These studies are always very complicated because the presence of pollutants needs to be weighed against the benefits that come from eating salmon, which are a good source of healthful omega-3 fatty acids.

Funding for the new Canadian study do include folks with an interest in promoting farmed salmon, or aquaculture. They include: AquaNet, Fisheries and Oceans Canada–Aquaculture Collaborative Research and Development Program, the British Columbia Salmon Farmers Association, the British Columbia Science Council and the former federal Office of the Commissioner for Aquaculture Development.

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Canadian farmed salmon lower in mercury than wild fish