File Geodatabase Feature Class
Tags
freshwater, biota, environment, Sacramento River, salinity, estuarine, sampling, California, Suisun Bay, marine, cancer crab, otter trawl, California Delta, temperature, San Francisco Bay, midwater trawl, Carquinez Strait, shrimp, San Pablo Bay, San Joaquin River
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, caridean shrimp and Cancer crabs throughout the lower San Francisco estuary.
The range of sampling extends from immediately south of the Dumbarton Bridge, to just west of Alcatraz Island, throughout San Pablo and Suisun bays, north to the confluence of the Sacramento River and Steamboat/Cache sloughs, and east to Old River Flats on the San Joaquin River. Fifty-two stations are sampled monthly: 35 original open water stations, seven stations added in 1988, four stations added in 1990, and six added in 1994. Sampling also included a beach seine survey (discontinued in 1987), a ringnet survey for crabs (discontinued in 1994), and a plankton net survey (discontinued in 1989). Bay Study uses a 42-foot stern-trawler with two types of trawl nets to conduct sampling. The otter trawl is towed against the current at a standard engine rpm for five minutes then retrieved. The midwater trawl is towed with the current at a standard engine rpm for 12 minutes and retrieved obliquely such that all depths are sampled equally. A five-to-one scope (ratio of cable out to depth) is used for both. Fish, caridean shrimp, and crabs are specieated, measured, and counted. Shrimp and crabs are also sexed. Sampling effort is quantified (i.e. distance towed, volume filtered) and electrical conductivity (converted to salinity), water temperature, secchi depth and station depth are measured; wave height, tide, cloud cover, and tow direction are categorized. Data is used for catch per unit effort (CPUE) calculations, as well as monthly and annual abundance indices.
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Disclaimer: The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.
Extent
| West | -122.475968 | East | -121.560792 |
| North | 38.178740 | South | 37.491556 |
| Maximum (zoomed in) | 1:5,000 |
| Minimum (zoomed out) | 1:150,000,000 |
Disclaimer: The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.