Science activity

Description The Enhanced Delta Smelt Monitoring (EDSM) program is a year-round monitoring program comprised of multiple crews trawling concurrently at multiple sites in predefined strata within the San Francisco Estuary. Post-larval Delta Smelt are targeted approximately April through June using 20mm trawling gear, and Kodiak trawling gear is employed the remainder of the year. Gear efficiency experiments and shallow water sampling elements are incorporated when possible. Need The declining Delta Smelt population has highlighted the need to keep improving the array of information that supports our understanding of the factors affecting Delta Smelt population dynamics and management decisions to minimize adverse effects of water operations on the population. EDSM has biological significance and potential conservation benefit by providing data to resource managers on nearly all life stages of endangered Delta Smelt and near-real-time data on the juvenile and adult life stages. EDSM data is provided to the Smelt Working Group and other managers in near realtime to help inform management decisions during the entrainment season. Objectives • To estimate the total abundance of Delta Smelt, along with standard errors or confidence intervals, on a weekly to bi-weekly basis for various life stages (postlarvae, juveniles, sub-adults, adults) throughout the year; • To estimate the spatial distribution of Delta Smelt at a management relevant temporal and spatial resolution;and • To provide data that support management decisions and address scientific questions to further understanding of sampling efficiency, drivers of Delta Smelt population patterns, and other conservation and management-relevant topics.