Simon, C., Satterthwaite, W.H., Beakes, M.P., Collins, E., Swank, D.R., Merz, J.E., Titus, R.G., Sogard, S.M., and M. Mangel
11/07/2010 09:00 AM
Applied Mathematics & Statistics
We fit a bioenergetics model based on a balance between mass and temperature-dependent anabolic and catabolic factors to growth data for juvenile steelhead trout (Oncorhynchus mykiss) from California. We grew sh from a small coastal stream (Scott Creek) conservation hatchery and a Central Valley (Coleman National Fish Hatchery on Battle Creek, Sacramento River) production hatchery in a common laboratory setting. Our growth model did not characterize the trajectories of all sh, likely as a consequence of enhanced growth via cannibalism or inhibited growth due to risk averse behavior such as avoidance of dominant individuals. For most individuals, however, it provides a close match and allows us to provide an excellent description of individual and stock-specic variation in specic rates of anabolism and catabolism. We use likelihood methods to conclude that there is a strong dierence in the mean rates based on origin of the stock, with Central Valley fish having a higher maximal consumption ability but both strains having similar metabolic needs after standardizing for sh size and temperature. This suggests genetic differences between strains base on local adaptation and/or diering degrees of domestication). As a result, environmental change may aect the growth (and thus survival, life history, and demography) of the strains in dierent ways.
