Herring and black-backed gulls as indicators of contaminants in bald Eagles in Lake Ontario

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:37372

Weseloh, D V; Ewins, P J ^[1]

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1. Environment Canada, Burlington, Ontario (Canada). Canadian Wildlife Service

Fresh eggs of Herring (HERG) and Great Black-backed (GBBG) Gulls were collected from the same three sites in eastern Lake Ontario, the only area of the Great Lakes where GBBGs regularly nest. Weighted mean contaminant levels (mg/kg, wet weight) in GBBG eggs (DDE = 13.44, PCBs (sum of congeners) 27.45, mirex 2.07, dieldrin = 0.3116, HCB = 0.1055 and HE = 0.1223) averaged 2.24x greater than in HERG eggs (range 1.9--2.6 greater). Because of the suspected overlap in the diet of GBBGs and Bald Eagles (i.e. young gulls, scavaged fish and waterfowl), the authors feel the two species probably occupy a similar trophic level in the Lake Ontario food web and thus may have similar contaminant levels. Lake Ontario is the only one of the Great Lakes where eagles do not currently nest. If Bald Eagles were to start nesting in Lake Ontario and accumulated egg levels of DDE and PCBs similar to those in Lake Ontario GBBGS, those nests would probably fail as these levels are above those associated with nest failure during the 1970s.

• OSTI ID: 37372
• Report Number(s): CONF-9410273--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
AQUATIC ORGANISMS
BIOLOGICAL INDICATORS
BIRDS
LAKE ONTARIO
POLYCHLORINATED BIPHENYLS
SENSITIVITY
TOXICITY
WATER POLLUTION