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Organochlorine contaminants and reproductive success of double-crested cormorants from Green Bay, Wisconsin, USA

Environmental Toxicology and Chemistry

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Abstract

In 1994 and 1995, nesting success of double-crested cormorants (Phalacrocorax auritus) was measured at Cat Island, in southern Green Bay, Lake Michigan, Wisconsin, USA. Sample eggs at pipping and unhatched eggs were collected and analyzed for organochlorines (including total polychlorinated biphenyls [PCBs] and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in embryos, and eggshell thickness. Of 1,570 eggs laid, 32% did not hatch and 0.4% had deformed embryos. Of 632 chicks monitored from hatching to 12 d of age, 9% were missing or found dead; no deformities were observed. The PCB concentrations in sample eggs from clutches with deformed embryos (mean = 10.2 I?g/g wet weight) and dead embryos (11.4 I?g/g) were not significantly higher than concentrations in sample eggs from nests where all eggs hatched (12.1 I?g/g). A logistic regression of hatching success versus DDE, dieldrin, and PCB concentrations in sibling eggs identified DDE and not dieldrin or PCBs as a significant risk factor. A logistic regression of hatching success versus DDE and eggshell thickness implicated DDE and not eggshell thickness as a significant risk factor. Even though the insecticide DDT was banned in the early 1970s, we suggest that DDE concentrations in double-crested cormorant eggs in Green Bay are still having an effect on reproduction in this species.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Organochlorine contaminants and reproductive success of double-crested cormorants from Green Bay, Wisconsin, USA
Series title:
Environmental Toxicology and Chemistry
Volume
18
Issue:
6
Year Published:
1999
Language:
English
Contributing office(s):
Upper Midwest Environmental Sciences Center
Description:
pp. 1209-1217
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1209
Last page:
1217
Number of Pages:
9