SS1.02 Geochemical Tracers in Calcified Structures: Implications for Fisheries Research
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
DufourE, Syracuse University, Syracuse, USA, edufour@syr.edu
Patterson, W, P, Syracuse University, Syracuse, USA, wppatter@syr.edu
 
ASSESSMENT OF THE ROLE OF ENVIRONMENTAL THERMAL VARIATIONS IN RECRUITMENT OF LAKE MICHIGAN ALEWIFE
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The ability to properly manage alewife (Alosa sapidissima) in Lake Michigan remains linked to a better understanding of mechanisms controlling its recruitment. Understanding the nature of alewife recruitment needs to determine (1) environmental factors that contribute to variability in the first year of life and (2) relative contributions from distinctively different habitats - Lake Michigan and drowned river-mouth embayments. Variation of temperature, through its influence on alewife spawning behavior, larval and juvenile growth rates, prey and predator variability, and overwinter mortality may determine the temporal and spatial variance in optimal habitat for alewife production and thus may play a key role in interannual variations in alewife abundance. In order to test this hypothesis, we performed stable isotope measurements of oxygen and carbon on sagittal otoliths of survival YOY and adults caught in different sites of the lake. Transects of micromilled samples are used to determine the natal origin and thermal history of fishes.