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Ice Fishing in the Saguenay Fjord

Savard, M. 2003. Étude toxicologique sur la consommation de poisson de pêche blanche sur le fjord du Saguenay, Direction de santé publique, Agence de développement de réseaux locaux de services de santé et de services sociaux du Saguenay-Lac Saint-Jean, 188 p. + annexes.

Translated summary of Étude toxicologique sur la consommation
de poisson de pêche blanche sur le fjord du Saguenay (Toxicological Study on Fish Consumption of Ice Fishing in the Saguenay Fjord)

From late December to mid-March, more than 5,000 sport fishing enthusiasts gather on the frozen surface of Quebec’s Saguenay River to catch smelt and groundfish (rockfish, cod and halibut). The number of fishers can double on winter weekends when the weather is favourable. For this study, the authors examined historical data on ice fishing on the Saguenay, characterized fishers’ consumption habits, and considered current levels of contamination among species most commonly fished in winter as well as the results of blood tests on some sixty fishers to estimate exposure levels among high-level fish consumers and to evaluate whether fish caught in the Saguenay fjord are safe to eat, based on marketing standards as well as human health criteria.

The authors observed that levels of mercury, polychlorinated biphenyl (PCB) and organochlorine pesticide (including chlordane and hexachlorobenzene) contamination in persons consuming fish from the Saguenay increase significantly according to frequency of fish consumption, but the levels do not exceed the criteria or risk estimators for protection of public health. Because of the seasonal nature of winter-caught fish consumption, mercury contamination levels observed at season’s end remain, on average, about three times lower than those of the exposure scenarios; moreover, during the summer season they do not exceed the ceiling levels for regular consumers of speckled trout. Generally speaking, levels of PCB and organochlorine pesticide contamination among high-level fish consumers in the Saguenay region are comparable to those observed for high-level fish consumers in the Lake Ontario and Mississauga freshwater reach regions. They are, however, lower than those measured in fishers in the Montreal region—anywhere from three to ten times lower, depending on the contaminant. It was not possible to measure levels of dioxins and furans with sufficient precision; overall, however, they are close to the background level established for urban populations in the Great Lakes and Montreal regions.

After consideration of all the data collected, the authors conclude that seasonal consumption of smelt, rockfish and ogac (fjord cod) poses no public health risks, as long as ice fishing enthusiasts who continue to fish and eat their catches during the summer season follow the recommendations of the Quebec Guide de consommation de poisson de pêche sportive en eau douce.

Mercury remains the contaminant most in need of monitoring; because of the lack of data on bioaccumulation in rockfish, ogac, Atlantic cod and Greenland halibut, the authors were unable to provide toxicological hazard estimates for other age classes of these groundfish species. Data on accumulation of organochlorines (notably pesticides and PCBs) in fatty fish such as rockfish and Greenland halibut remain too fragmentary to permit a more precise toxicological hazard estimate.