Marine Biology Seminar: Dr. Levi Lewis (UC Davis)
Title: Listening to Ears: Geochemical Exploration of the Life-history Strategies used by Endangered Fishes of the San Francisco Estuary
(Talk will be given remotely over Zoom)
Abstract: Over the last 40 years, San Francisco populations of Longfin Smelt (Spirinchus thaleichthys) and endemic Delta Smelt (Hypomesus transpacificus) have collapsed to just 1% of their historic abundance, resulting in state and federal protections and targeted conservation efforts. Despite many decades of intensive monitoring throughout the region, multiple conflicting descriptions of the life histories, spawning habitats, and movement patterns of these species have persisted, each with important implications for water policy decisions that impact California’s multi-billion-dollar agriculture business and 29 million southern residents. Using expanded field surveys and otolith geochemistry, we re-examined the movement patterns, habitat use, and life-history strategies employed by these imperiled native fishes. Our results uncovered previously undescribed life history strategies that likely once facilitated population resilience within a dynamic and unpredictable estuarine environment. These findings challenge existing population models for these species and could be key to informing water management policies in California that aim to balance human uses with environmental protection.