Transfer of mercury from benthic invertebrates to fishes in lakes with contrasting fish community structures

Abstract

Abstract:We examined the flow of mercury (Hg) from benthic invertebrates to fishes in lakes with contrasting fish community structure. The study was carried out in two whole lakes in southcentral Ontario in 1992. Both were remote from direct sources of contamination and were chosen because of their physical and chemical similarities. Although the fish communities in the two lakes were qualitatively similar, the total number of fishes in Ranger Lake was an order of magnitude smaller than that in Mouse Lake. As a result of the lower net predation from benthivorous fishes, documented in earlier studies, Ranger Lake benthic invertebrate populations were significantly higher. However, benthic invertebrate taxa in Mouse Lake were generally larger and had higher Hg concentrations. This was partly attributed to the stunted growth of Mouse Lake fishes, which did not allow them to prey on larger benthos as a result of gape limitations. Despite the lower Hg concentrations in Ranger Lake benthos, total benthic invertebrate Hg pools were higher in this lake as a result of its higher total benthic invertebrate biomass. However, the transfer of total Hg from benthic invertebrates to fishes was higher in Mouse Lake due to the higher consumption rates of benthivorous fishes.Résumé : Nous avons examiné le flux du mercure (Hg) des invertébrés benthiques aux poissons dans des lacs ayant des communautés de poissons de structure différente. L'étude a été réalisée dans deux lacs entiers dans le centre-sud de l'Ontario en 1992. Les deux lacs étaient éloignés des sources de contamination directe et ils ont été choisis en raison de leur ressemblance du point de vue physique et chimique. Bien que les communautés de poissons dans les deux lacs aient été semblables du point de vue qualitatif, le nombre total de poissons dans le lac Ranger était inférieur d'un ordre de grandeur à celui du lac Mouse. À cause de la prédation nette inférieure attribuable aux poissons benthivores, documentée dans des études antérieures, les populations d'invertébrés benthiques du lac Ranger étaient substantiellement plus importantes. Cependant, les représentants des taxons d'invertébrés benthiques du lac Mouse étaient généralement de taille plus grande et avaient des concentrations de Hg plus élevées. Cette situation était en partie attribuable à la croissance arrêtée des poissons du lac Mouse, qui ne leur permettait pas de consommer les organismes benthiques plus gros en raison d'une ouverture maximale de la bouche insuffisante. Malgré les concentrations de Hg inférieures dans le benthos du lac Ranger, les pools de Hg chez les invertébrés benthiques étaient plus importants dans ce lac en raison de sa biomasse totale en invertébrés benthiques plus élevée. Toutefois, le transfert de Hg des invertébrés benthiques aux poissons était plus élevé dans le lac Mouse en raison du taux de consommation plus élevé des poissons benthivores. [Traduit par la Rédaction]

Mercury in the Northern Crayfish, Orconectes virilis (Hagen), in New England, USA

“…Parkman and Meili (1993) and Wong et al (1997) found a correlation between total Hg concentration and predatory insect weight when compared across all taxonomic groups; however, they did not find a relationship within taxa. They suggested that life cycle duration had little to do with mercury accumulation; rather, trophic status of the invertebrate was the key factor in determining mercury levels.…”

“…Determining the environmental factors responsible for mercury levels observed within organisms remains elusive although several key parameters have been correlated with high mercury or methylmercury levels in fish. For example, increasing trophic position (Spry and Weiner, 1991;Jackson, 1998), body size (Scott and Armstrong, 1972;Scott, 1974;Wren et al, 1983), age (Simonin et al, 1994), dissolved organic carbon (DOC) concentration (Driscoll et al, 1995;Wiener and Spry, 1996), pH (Cope et al, 1990;Grieb et al, 1990;Haines et al, 1992), food web complexity (Futter, 1994;Wong et al, 1997;Chen et al, 2000), degree of flooding (Jackson, 1991;Johnston et al, 1991;McNicol et al, 1997), and percent of watershed with wetland habitats (Jackson, 1988;McMurty et al, 1989), have all been variously associated with mercury levels in fish or fish-eating birds and mammals.…”

Mercury Trophic Transfer in a Eutrophic Lake: The Importance of Habitat‐specific Foraging

“…Benthic secondary productivity has been shown to be correlated with pelagic energy sources (Chandra et al 2005) and may be strongly linked in eutrophic systems such as Clear Lake (Welch et al 1988). Moreover, benthic Hg bioaccumulation pathways can be significant (Wong et al 1997, Mason et al 2000, suggesting that integration of both routes is required for proper assessment.…”

Assessment of mercury bioaccumulation within the pelagic food web of lakes in the western Great Lakes region

“…The efficiency of MeHg transfer within the aquatic food web is in turn influenced by trophic (biological) factors, most notably the number of trophic positions involved, feeding and growth rates, dietary constraints, behavior, cannibalism, and organism condition (Wong et al 1997;Gorski et al 2003;Wiener et al 2003;Dittman and Driscoll 2009). For e.g., Wong et al (1997) observed higher MeHg concentrations in benthic invertebrates in an Ontario lake where stunted benthivorous fish had too small of a gape to eat larger individuals, thus selecting for collection and measurement of larger, MeHg-laden organisms.…”