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Title: Exposure of great egret (Ardea albus) nestlings to mercury through diet in the Everglades ecosystem

Abstract

The authors estimated exposure of great egret (Ardea albus) nestlings to mercury in food in the Florida Everglades, USA, by collecting regurgitated food samples during the 1993 to 1996 breeding seasons and during 1995 measured concentrations of mercury in individual prey items from those samples. Great egret nestlings had a diet composed predominantly of fish, though the species composition of fish in the diet fluctuated considerably among years. Great egrets concentrated on the larger fish available in the marsh, especially members of the Centrarchidae. The importance of all nonnative fish fluctuated from 0 to 32% of the diet by biomass and was dominated by pike killifish (Belonesox belizanus) and cichlids (Cichlidae). Total mercury concentrations in prey fish ranged from 0.04 to 1.40 mg/kg wet weight, and they found a significant relationship between mass of individual fish and mercury concentration. The authors estimated the concentration of total mercury in the diet as a whole by weighting the mercury concentration in a given fish species by the proportion of that species in the diet. They estimate that total mercury concentrations in the diets ranged among years from 0.37 to 0.47 mg/kg fish. The authors estimated total mercury exposure in great egret nestlingsmore » by combining these mercury concentrations with measurements of food intake rate, as measured over the course of the nestling period in both lab and field situations. They estimate that, at the 0.41 mg/kg level, nestlings would ingest 4.32 mg total mercury during an 80-day nestling period. Captive feeding studies reported elsewhere suggest that this level of exposure in the wild could be associated with reduced fledgling mass, increased lethargy, decreased appetite, and, possibly, poor health and juvenile survival.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Univ. of Florida, Gainesville, FL (US)
OSTI Identifier:
20006625
Alternate Identifier(s):
OSTI ID: 20006625
Resource Type:
Journal Article
Journal Name:
Environmental Toxicology and Chemistry
Additional Journal Information:
Journal Volume: 18; Journal Issue: 9; Other Information: PBD: Sep 1999; Journal ID: ISSN 0730-7268
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 56 BIOLOGY AND MEDICINE, APPLIED STUDIES; WATER POLLUTION; MERCURY; BIOLOGICAL INDICATORS; FISHES; BIRDS; FOOD CHAINS; FLORIDA; NATURE RESERVES

Citation Formats

Frederick, P.C., Spalding, M.G., Sepulveda, M.S., Williams, G.E., Nico, L., and Robins, R. Exposure of great egret (Ardea albus) nestlings to mercury through diet in the Everglades ecosystem. United States: N. p., 1999. Web. doi:10.1897/1551-5028(1999)018<1940:EOGEAA>2.3.CO;2.
Frederick, P.C., Spalding, M.G., Sepulveda, M.S., Williams, G.E., Nico, L., & Robins, R. Exposure of great egret (Ardea albus) nestlings to mercury through diet in the Everglades ecosystem. United States. doi:10.1897/1551-5028(1999)018<1940:EOGEAA>2.3.CO;2.
Frederick, P.C., Spalding, M.G., Sepulveda, M.S., Williams, G.E., Nico, L., and Robins, R. Wed . "Exposure of great egret (Ardea albus) nestlings to mercury through diet in the Everglades ecosystem". United States. doi:10.1897/1551-5028(1999)018<1940:EOGEAA>2.3.CO;2.
@article{osti_20006625,
title = {Exposure of great egret (Ardea albus) nestlings to mercury through diet in the Everglades ecosystem},
author = {Frederick, P.C. and Spalding, M.G. and Sepulveda, M.S. and Williams, G.E. and Nico, L. and Robins, R.},
abstractNote = {The authors estimated exposure of great egret (Ardea albus) nestlings to mercury in food in the Florida Everglades, USA, by collecting regurgitated food samples during the 1993 to 1996 breeding seasons and during 1995 measured concentrations of mercury in individual prey items from those samples. Great egret nestlings had a diet composed predominantly of fish, though the species composition of fish in the diet fluctuated considerably among years. Great egrets concentrated on the larger fish available in the marsh, especially members of the Centrarchidae. The importance of all nonnative fish fluctuated from 0 to 32% of the diet by biomass and was dominated by pike killifish (Belonesox belizanus) and cichlids (Cichlidae). Total mercury concentrations in prey fish ranged from 0.04 to 1.40 mg/kg wet weight, and they found a significant relationship between mass of individual fish and mercury concentration. The authors estimated the concentration of total mercury in the diet as a whole by weighting the mercury concentration in a given fish species by the proportion of that species in the diet. They estimate that total mercury concentrations in the diets ranged among years from 0.37 to 0.47 mg/kg fish. The authors estimated total mercury exposure in great egret nestlings by combining these mercury concentrations with measurements of food intake rate, as measured over the course of the nestling period in both lab and field situations. They estimate that, at the 0.41 mg/kg level, nestlings would ingest 4.32 mg total mercury during an 80-day nestling period. Captive feeding studies reported elsewhere suggest that this level of exposure in the wild could be associated with reduced fledgling mass, increased lethargy, decreased appetite, and, possibly, poor health and juvenile survival.},
doi = {10.1897/1551-5028(1999)018<1940:EOGEAA>2.3.CO;2},
journal = {Environmental Toxicology and Chemistry},
issn = {0730-7268},
number = 9,
volume = 18,
place = {United States},
year = {1999},
month = {9}
}