Smelt Larva Survey

Program Overview

a long conical net laid out on the ground for display — **Smelt Larva Survey net.** *CDFW photo.*

map of smelt larva survey station in delta waters — **Map of the current Smelt Larva Survey sampling locations.** (click/tap to enlarge)

lab tech with tweezers and container of debris — **A crew member sorting out larval fish from debris in the lab.** *CDFW photo.*

The Smelt Larva Survey began in 2009 and provides near real-time distribution data for Longfin Smelt larvae in the Delta, Suisun Bay, and Suisun Marsh. These data are used by agency managers to assess vulnerability of Longfin Smelt larvae to entrainment in south Delta export pumps. The gear is highly efficient at retaining small larvae, and the project also collects data on other larval fish species.

Methods

The Smelt Larva Survey samples 35 fixed sites every other week from January through March. At each site, a single 10-minute oblique tow is conducted using a 500-micron mesh egg and larval net. Fish are collected in a cod end jar, preserved in neutral buffered formalin, then brought to the lab to be sorted and identified.