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Purpose/Objective: Determine the effects of freshwater outflow on the distribution
and abundance fish, caridean shrimp,
and Cancer crabs of San Francisco Estuary.
Geographic range of field work: Within San Francisco estuary, to just west of
Alcatraz Island, south to immediately south of the Dumbarton Bridge, east to the mouth of
Three Mile Slough on the Sacramento River and immediately upstream of the Antioch Bridge
on the San Joaquin River and north into Grizzly Bay.
Number of sites: The indices are generated using the original 35 open water sites; seven sites were added in
1988, four sites were added in 1990 and six sites were added in 1994. 27 shoreline sites were sampled with the beach seine.
Nine sites were sampled with ringnets and three sites were added in 1990.
Period of record: January 1980 to present for open water sampling, August 1980 through
January 1987 for beach seine sampling, and May 1982 to present for ringnet sampling.
Sample frequency per time unit: Monthly for all.
General category of data collected: Fish, caridean shrimp, and Cancer crabs are
speciated, measured, and counted. Shrimp and crabs are also sexed. For shrimp, egg and
ovary stage, presence of the branchial parasite Argiea and the presence of food in the
stomach are determined. Sampling effort is quantified (i.e. distance towed, volume filtered),
and electrical conductivity (converted to salinity), water temperature, secchi depth, station
depth and distance towed are measured; wave height, tide and cloud cover are categorized.
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