Green and White Sturgeon in the San Francisco Estuary
Using fin ray geochemistry to reconstruct habitat use and migration throughout the Delta, and to estimate population-level impacts of harmful algal blooms
Green and White Sturgeon are two closely related migratory fish species that migrate throughout the San Francisco Estuary (SFE), including the Delta, and surrounding Napa, Sacramento, and San Joaquin river watersheds. Sturgeon are long-lived, late-spawning species with highly variable life histories across individuals, adapted to the variable environmental conditions in California’s Central Valley and the Pacific Ocean.
Both species are impacted by water diversions, habitat modifications, overfishing, and water contaminants from agricultural, mining, and industrial activities. Consequently, both species are of management and conservation concern, with the Green Sturgeon southern DPS listed as threatened under the federal ESA. White Sturgeon are a species of special concern in the SFE but still support a sport fishery.
Both species were adversely impacted by the 2022 SFE harmful algal bloom (HAB), with hundreds of adult carcasses documented throughout the San Francisco Bay and along the Pacific coast. This project will provide critical life history information for Green and White Sturgeon in the SFE and directly contribute to ongoing conservation and management of these species by documenting age and migratory history from sturgeon collected during the HAB event and comparing those with fin rays collected from non-HAB periods to determine whether particular migratory types were disproportionately impacted.
Expected Benefits: Increased understanding of how environmental stressors such as HABs, likely to occur more frequently with climate change, are likely to impact Green and White Sturgeon age structure, habitat use, and migratory behavior. These are key knowledge gaps that currently hinder effective management of sturgeon.
