Lead effects on body composition and organ size of wintering canvasbacks Aythya valisineria in Louisiana
Pace, R.M., III, Hohman, W.L. & Custer, T.W. 1999: Lead effects on body composition and organ size of wintering canvasbacks Aythya valisineria in Louisiana. - Wildl. Biol. 5: 3-10.
We tested whether lead exposure, as evidenced by liver lead concentration, affected body composition and organ sizes of canvasback ducks Aythya valisineria in Louisiana during winter 1987-88. After adjusting for body size, sex, age, and site and month of collection, we found decreases in ingesta-free body mass; breast, leg, and body protein; body fat; intestine length; and liver and gizzard masses associated with increased liver lead concentrations. There were no apparent associations between liver lead concentrations and testes and body ash masses, or caecal length. We used the concentration of 26.7 ppm of liver lead on a dry matter (dm) basis as indicative of lead toxicosis. We predicted that a canvasback with 26.7 ppm dm liver lead would weigh 209 g less and have 105 g less fat than an unexposed individual. Whereas many lead exposed canvasbacks may survive through winter, their subsequent survival, ability to reproduce and perform other annual cycle events may be compromised. We recommend management to make lead unavailable to waterfowl at major concentration areas and periodic monitoring of lead contamination in waterfowl populations.
Key words: Anatidae, Aythya valisineria, condition, ducks, lead toxicosis
Richard M. Pace, III, U.S. Geological Survey, Biological Resource Division, Louisiana Cooperative Fish and Wildlife Research Unit, Louisiana State University, Baton Rouge, Louisiana 70803-6202, USA - e-mail: rpace@lsu.edu
William L. Hohman*, U.S. Geological Survey, Biological Resource Division, National Wetlands Research Center, 700 Cajundome Blvd., Lafayette, Louisiana 70506, USA
Thomas W. Custer, Upper Midwest Environmental Sciences Center, 2630 Fauta Reed Road, LaCrosse, Wisconsin 54602, USA
*Present Address: USDA/NRCS, Department of Animal Ecology, Iowa State University, 124 Science II, Ames, Iowa 5011, USA
Received 13 January 1998, accepted 27 July 1998
Associate Editor: Jesper Madsen