This contract continues a multi-year project as determined during the project selection process during 2006.  

American shad Alosa sapidissima are non-native anadromous clupeids that have become abundant in the Columbia River during the last 70 years, with adult counts at Bonneville Dam being as high as 5 million fish during recent years.  American shad adults, perhaps over 20 million, enter the lower Columbia River during April-June for spawning.  Juveniles out-migrate in vast numbers primarily during July through early winter, and evidence suggests that many overwinter in the estuary.

Previous years of this project investigated the diet of juvenile and adult American shad, developed a bioenergetics model for American shad, and investigated the role of American shad as a potential disease vector.  During this contract period the parameterization of the American shad bioenergetics model will be improved by incorporation of size-at-age information on larval and juvenile shad obtained by examining otoliths.  The American shad bioenergetics model will be corroborated with field and laboratory data and a parameter sensitivity analysis will be done to assess the physiological parameter estimates used.   Bioenergetics scenarios should help identify potential positive or negative impacts of American shad on the aquatic community.