Organic contaminants in lower Great Lakes\u27 waterfowl in relation to diet, with particular reference to Dreissena polymorpha.

Six species of waterfowl including greater scaup (Aythya marila), lesser scaup (Aythya affinis), bufflehead (Bucephala albeola), canvasback (Aythya valisineria), mallard (Anas platyrhynchos), and redhead (Aythya americana) were collected and analyzed for diet content, organic contaminant patterns (pesticides and polychlorinated biphenyls (PCBs)), and stable isotope (\sp{14}C and \sp{15}N) signatures from 3 sites in the lower Great Lakes (Fighting Island, western Lake Erie, and Big Creek). Lesser and greater scaup from Fighting Island were classified into groups according to the percentage dry mass of zebra mussel (Dreissena polymorpha) in the diet. Lesser and greater scaup classified as Dreissena-consumers had, on average, 85 and 67%, respectively, zebra mussel diet content as compared to 6 and 3% for individuals classified as macrophyte-consumers. Stable isotope analyses revealed that \u27Dreissena-consumer\u27 lesser and greater scaup were enriched 2.9\perthous and 2.4\perthous in \sp{15}N relative to \u27macrophyte-consumer\u27 conspecifics. As well, these \u27mussel-consumer\u27 waterfowl had 2.6\perthous and 2.3\perthous higher \sp{15}N levels relative to Dreissena, their principal prey. Using chemical octanol-water partition coefficients (K\rm\sb{ow}) a representative group of low-(pentachlorobenzene (QCB), polychlorinated biphenyl (PCB) # 28), mid-(PCBs # 105, 153) and high-(PCBs # 194, 206) K\rm\sb{ow} compounds were examined in liver tissues for each group of waterfowl. Results revealed significant differences with respect to diet for high-K\rm\sb{ow} compounds, though differences among species were insignificant. In each case, mussel-consumers had elevated concentrations of these compounds relative to individuals that avoided Dreissena. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1995 .M39. Source: Masters Abstracts International, Volume: 34-06, page: 2297. Adviser: Hugh J. MacIsaac. Thesis (M.Sc.)--University of Windsor (Canada), 1995

Influence of Feeding Habits on Organochlorine Contaminant Accumulation in Waterfowl on the Great Lakes

Zebra mussels (Dreissena polymorpha) are an important component of benthic communities in the Great Lakes and are exploited by a host of predators, including waterfowl. In this study, we analyze diet content and stable isotope and organochlorine contaminant patterns in Lesser Scaup (Aythya affinis), Greater Scaup (Aythya marila), Bufflehead (Bucephala albeola), Redhead (Aythya americana), Canvasback (Aythya valisineria), and Mallard (Anas platyrhynchos) collected from three sites (Fighting Island, western Lake Erie, Big Creek) in the lower Great Lakes. Lesser and Greater Scaup from Fighting Island were classified as either zebra mussel ( ≥ 67% of diet) or macrophyte ( ≥ 85% of diet) consumers. Bufflehead, Canvasback, Mallard, and Redhead consumed mainly ( ≥ 89%) macrophyte at Fighting Island. Zebra mussel was the principal food of Lesser Scaup ( \u3e 99%), Greater Scaup (97%), and Bufflehead (72%) in western Lake Erie. Stable isotope analysis revealed enrichment of δ15N in Lesser Scaup ( ≥ 2.24‰), Greater Scaup ( ≥ 1.28‰), and Bufflehead ( ≥ 0.63‰) that exploited mussels relative to conspecifics with macrophyte diets and relative to mussel prey. Representative contaminants of low (hexachlorobenzene [HCB]), moderate (PCB [polychlorinated biphenyl] 153), and high (PCB 180) hydrophobicity were examined in waterfowl. Lipid-normalized concentrations of PCBs 153 and 180 were significantly higher in scaup and Bufflehead that consumed Dreissena than in individuals that ate mainly macrophytes. Among taxa that consumed primarily Dreissena concentrations of PCBs 153 and 180 were significantly higher in individuals from Lake Erie than in those Fighting Island. Principal components analysis revealed broad differences in contaminant patterns of waterfowl based principally on diet. Results from this study illustrate that Dreissena has become a primary food source of some waterfowl in the lower Great Lakes and serves as an effective conduit for transfer of persistent organic contaminants to higher trophic levels