The United States Fish and Wildlife Service’s (USFWS) Experimental Larval Survey was designed and implemented by the Enhanced Delta Smelt Monitoring Program to assess alternative sampling methods for monitoring the larval life stages of the federally endangered Delta Smelt (Hypomesus transpacificus) within the San Francisco Estuary, California, USA. From 2018 to 2019, four different sampling methods (Beach Seine, Manta Trawl Net, 20-mm Surface Trawl Net, 20-mm Midwater Trawl Net) nested in time and space were used to estimate the occupancy rate, relative density, and size distribution of larval Delta Smelt across sampling methods and water depth strata within the San Francisco Estuary. For more information on the Lodi USFWS Office and the Enhanced Delta Smelt Monitoring Program: https://www.fws.gov/lodi/.

The U.S. Fish and Wildlife Service (USFWS) Lodi Fish and Wildlife Office (LFWO) Delta Juvenile Fish Monitoring Program (DJFMP) has intermittently sampled Liberty Island with various equipment since 2002. Liberty Island was a reclaimed agricultural island until it flooded in 1997-1998 and we subsequently left to passively restore as a tidally influenced wetland. Larval trawls and beach were the only sampling methods used during both early (2002-2005) and late (2009-2019) sampling periods. The main purpose of the sampling was to gather information about fish presence and abundance in Liberty Island during the passive restoration, with an emphasis on reproductive and early life-stages of native species. Larval trawls, or tow nets, were used to catch larval fish in 2004-2005 and again from 2013-2019. Zooplankton nets were used 2013-2019. Water quality measurements were collected alongside each tow.

The Enhanced Delta Smelt Monitoring Program (EDSM) was initiated by the U.S. Fish and Wildlife Service in 2016. EDSM focuses on providing real-time data to help managers respond to population patterns of Delta Smelt within the upper San Francisco Estuary, primarily by providing estimates of Delta Smelt distribution and abundance. The dataset can also be useful in evaluating habitat use and behavior patterns of this species and other fish species of interest. Sampling is done year round via Kodiak trawls and larval (“20-mm”) gear to sample Delta Smelt across most life stages. Sites are chosen via stratified random sampling. Over the course of a week, field crews sample between 18 and 41 random sites. A minimum of two tows are conducted at each site. All fish collected are identified (in the field when possible, in the lab for early life stages), measured, enumerated, and recorded. In addition to fish information, environmental data are collected for each sampling event. For more information: https://www.fws.gov/project/enhanced-delta-smelt-monitoring-program

The United States Fish and Wildlife Service Delta Juvenile Fish Monitoring Program (DJFMP) has monitored juvenile Chinook Salmon Oncorhynchus tshawytscha and other fish species within the San Francisco Estuary (Estuary) since 1976 using a combination of surface trawls and beach seines. Since 2000, three trawl sites and 58 beach seine sites have been sampled weekly or biweekly within the Estuary and lower Sacramento and San Joaquin Rivers. As part of the Interagency Ecological Program (IEP) that manages the Estuary, the DJFMP has tracked the relative abundance and distribution of naturally and hatchery produced juvenile Chinook Salmon of all races as they outmigrate through the Sacramento-San Joaquin Delta for over four decades. The data that DJFMP collected has been used not only to help inform the management of Chinook Salmon, but also to monitor the status of native species of interest such as the previously listed Sacramento Splittail Pogonichthys macrolepidotus and invasive species such as Mississippi Silverside Menidia beryllina and Largemouth Bass Micropterus salmoides.For more information: https://www.fws.gov/lodi/juvenile_fish_monitoring_program/