Species‐specific mercury bioaccumulation in a diverse fish community

Abstract

Mercury bioaccumulation models developed for fish provide insight into the sources and transfer of Hg within ecosystems. Mercury concentrations were assessed for 16 fish species of the western reach of Lake Diefenbaker, Saskatchewan, Canada. For top predators (northern pike, Esox Lucius; walleye, Sander vitreum), Hg concentrations were positively correlated to δ(15)N, and δ(15)N to fish age, suggesting that throughout life these fish fed on organisms with increasingly higher trophic values and Hg concentrations. However, fish mass and/or age were the principal parameters related to Hg concentrations for most species. For 9 common species combined, individual variation in Hg concentration was explained in declining order of importance by fish mass, trophic position (δ(15)N), and fish age. Delta (15)N value was not the leading variable related to Hg concentration for the assemblage, probably because of the longevity of lower--trophic-level species (3 species ≥ 20 yr), substantial overlap in Hg concentration and δ(15)N values for large-bodied fish up to 3000 g, and complex relationships between Hg concentration and δ(15)N among species. These results suggest that the quantity of food (and Hg) consumed each year and converted to fish mass, the quantity of Hg bioaccumulated over years and decades, and trophic position were significant determinants of Hg concentration in Lake Diefenbaker fish.

Isotopic Structure of Lake Whitefish in Lake Huron: Evidence for Regional and Local Populations Based on Resource Use

“…Therefore, sampling similarly sized adults (1-2 kg in this study) from different sites is an appropriate strategy for comparing resource use by spawning-phase adults. Sizeisotope relationships should be reevaluated if multiple life stages or size-classes are included in future analyses (but see Donald et al 2015).…”

Ratio of Mercury Concentration to PCB Concentration Varies with Sex of White Sucker (Catostomus commersonii)

“…In addition, the Hg concentration in the white suckers from the Kewaunee River population was lower than the Hg concentration in the white suckers from Lake Diefenbaker, a reservoir in Saskatchewan (Canada) with no known upstream anthropogenic point sources of mercury. The muscle tissue Hg concentrations of Lake Diefenbaker white suckers averaged 161 ng/g [56]. Applying the abovementioned conversion factor yielded an estimate of the whole-fish Hg concentration of 145 ng/g.…”

Water chemistry, landscape, and spatial controls of δ13C and δ15N of zooplankton taxa in boreal lakes: One size does not fit all

“…Preceding the analyses, all independent variables except pH were either log 10 ( x + 0.01) or log 10 ‐transformed to reduce the skewness, which allowed fitting linear models with zooplankton and DOM SI data. We used the information–theoretic approach to select best explanatory models for each case (Burnham & Anderson, ), while following the approach of Donald, Wissel, and Anas () to address high multicollinearity among predictors. First, we fitted a global model for carbon/nitrogen SI composition of each taxon with all potential predictors (separately for CHEM and HYDR_LAND) and checked for multicollinearity.…”