PW08 Aquatic Ecotoxicology II
Exhibit Hall
8:00 AM - Wednesday
(PW126) Potential impacts of uranium milling effluent on bioenergetics, growth, and site fidelity of juvenile fishes.
Bennett, P1, Janz, D1, 1 University of Saskatchewan, Saskatoon, SK, Canada
ABSTRACT- Maintenance of a healthy fish population is primarily influenced by recruitment of new individuals into the population. Survival of juvenile fish beyond their first year is an ecologically important determinant of recruitment, particularly in north temperate aquatic systems with prolonged overwintering periods. Uranium milling effluent contains elevated levels of various metals and salts, acting as potential stressors in receiving aquatic ecosystems. To evaluate possible impacts on native fishes, bioenergetics, growth and site fidelity of juvenile northern pike (Esox lucius) and white sucker (Catostomus commersoni) were determined downgradient of a uranium milling operation in northern Saskatchewan, Canada. Bioenergetics and growth were determined by evaluating seasonal changes in biochemical (total lipids, triglycerides, RNA/DNA ratio and proteins) and morphometric (length, weight and condition factor) measures of condition in fish collected from reference and impacted lakes. Northern pike collected from two lakes receiving mill effluent in fall 2003 had significantly greater total body lipids and total body triglycerides compared to fish collected from a reference lake. Total length, weight, condition factor and muscle protein levels were not significantly different among pike collected from exposure lakes and the reference lake. Fish collections in spring 2004 and resulting analyses will provide information on potential overwinter effects on biochemical and morphometric measures of condition. Summer field work will include passive integrated transponder (PIT) tagging of juvenile fish to assess site fidelity and investigate temporal changes in growth and condition. These data will increase our understanding of potential influence of metal mining on native fish species inhabiting northern aquatic ecosystems.
Key words: juvenile fishes, overwinter survival, bioenergetics , uranium milling