More than bags of nutrients: Weighing ecological and social costs of losing migratory fishes versus the management paradigm of compensatory mitigation

Document Type

Conference Proceeding

Publication Date



Fish migrations connect aquatic habitats around the world, and interactions and mortality associated with these extends their ecological influence to terrestrial habitats as well. In temperate settings, dramatic examples include the spawning migrations and mass mortality of anadromous species (e.g., Pacific salmon, steelhead and lamprey), but many non-anadromous species also exhibit migrations with attendant ecological roles. Fish migrations have a long history of providing diverse provisioning and cultural ecosystem services to humans, but are imperiled phenomena due to extirpation or loss of life-history forms. In turn, ecological roles that were multi-dimensional have been lost or homogenized. Often these changes have spanned several human generations, and knowledge of historic magnitudes of migrations is passing into legend, constituting a vanishing frame of reference for natural resource managers and the public. In its place, a paradigm of mitigation has arisen, whereby credit is assigned for attempts to offset, compensate for, or alleviate losses. However, this paradigm is rooted in assumptions. Do these align with empirically-derived ecological understanding, and do they reflect the full suite of human values associated with these fishes? Here, we address these questions with a focus on Pacific salmon, based upon results of our investigations and synthesis of ecological literature.

Publication Title

100th ESA Annual Meeting