Factors Contributing to the Population Resilience of Anadromous and Resident Salmonids

Life history diversity in salmonid species often has been cited as an evolutionary, bet-hedging strategy that strengthens population resilience in highly variable aquatic environments. However, surprisingly few studies have quantified, tested, or validated the contributions of life history variations to salmonid resilience. Moreover, the metrics and criteria for measuring resilience remain poorly defined but have become increasingly important as fisheries managers struggle to adapt to rapidly changing environments and aquatic species declines. The objective of this symposium is to explore the relationship between life history diversity and population resilience of resident and anadromous salmonids through a series of case studies from around the world.  The case studies examine: (1) variations in juvenile or adult life history attributes within and between populations, including diversity of ecological, migratory, or reproductive behaviors; and (2) the contribution of different life history attributes to long-term reproductive success under changing environmental conditions.  To compare salmonid life history responses, the symposium encompasses a wide array of geographic locales, environments, and resident and anadromous species across the breadth of Salmoniformes. Inter-population comparisons will assess geographic variations in life history attributes and the influence of metapopulation structure on salmonid resilience. We also will explore the implications of these results for salmonid conservation and recovery.