Interagency Ecological Program: San Francisco Bay Study Survey for Fish and Mobile Crustaceans 1980-2024

The San Francisco Bay Study (Bay Study) was established in 1980 to determine the effects
of freshwater outflow on the abundance and distribution of fish and mobile crustaceans
(brachyuran crabs and caridean shrimp) in the San Francisco Estuary, mainly downstream of
the Sacramento-San Joaquin Delta. The Bay Study survey currently samples 52 open-water
stations monthly from a research vessel with two types of trawl gear: a midwater trawl to
sample pelagic fishes, and an otter trawl to sample demersal fishes, crabs, and shrimp.
Historically, the study also included plankton sampling (1980-1989) for larval fish and
crustaceans. Fish collected by the otter and midwater trawl are identified to species,
counted, and a representative subsample is measured. In addition, crabs from the otter trawl
are identified, counted, sexed, and measured, and gelatinous zooplankton from the midwater
trawl are identified and counted. Shrimp are retained from each otter trawl sample and
returned to the laboratory for processing, which includes identification, counts, sex, and
length. Additional data collected at each station includes water depth, Secchi, and a water
column profile of temperature and conductivity. This data publication includes fish, crab,
shrimp, gelatinous zooplankton (jellies), and water quality data. Metadata related to the
plankton sampling will be included in the future when this data is published.