Salmonid Lfie History Variation and Its Implications for Fisheries

Predicting salmonid run sizes remains a vexing and important problem in population biology and the management of salmonid species.  This is due in part because of the two life history transitions that the fish make, movement from fresh water to the ocean (smolting) and from the ocean back to fresh water (maturation).  It is clear that most salmonids do not behave in stereotypical ways, but have a genetic program that is cued to environmental signals.  I will explain the components of a life history theory that combines proximate (physiological) and ultimate (evolutionary) considerations in a consistent manner.  This theory has been successfully applied to Atlantic salmon, charr, and steelhead.  I will show how it can guide us new ways for predicting run sizes from environmental information.