temperature
Significant results of monitoring
- The young striped bass abundance index has declined from
levels exceeding 100 in the 1960's to a record low of 4.3 in
1990.
- From 1959 to 1970, fluctuations in the annual index were
closely associated with both Delta outflow and the percent of
inflow being diverted by Central Valley Project, State Water
Project and Delta agriculture. Since 1971, the index has been
lower than expected mainly due to diversions in the Delta.
- The most probable cause of the decline in young striped bass
production is that the adult population, reduced due to
cumulative past entrainment losses, is not producing enough eggs
to maintain the population under present conditions.
Significant reports and publications:
California Department of Fish and Game. 1987. Factors affecting
striped bass abundance in the Sacramento-San Joaquin River
System. Exhibit 25 for the State Water Quality Resources
Control Board 1987 Water Quality/Water Rights Proceeding on
the San Francisco Bay and Sacramento-San Joaquin Delta.
Interagency Ecological Study Program Technical Report 20.
California Department of Fish and Game. 1992. A re-examination
of factors affecting striped bass abundance in the
Sacramento-San Joaquin Estuary. WRINT-DFG-Exhibit 2.
Chadwick, H.K. 1964. Annual abundance of young striped bass,
Roccus saxatilis, in the Sacramento-San Joaquin Delta,
California. California Fish and Game 50(2):69-98.
Kohlhorst, D.W., D.E. Stevens and L.W. Miller. 1992. A model
for evaluating the impacts of freshwater outflow and export
of striped bass in the Sacramento-San Joaquin Estuary.
WRINT-DFG-Exhibit 3.
Stevens, D.E., D.W. Kohlhorst, L.W. Miller and D.W. Kelley.
1985. The decline of striped bass in the Sacramento-San
Joaquin Estuary, California. Transactions of the American
Fisheries Society 114:12-30.
Turner, J.L. and H.K. Chadwick. 1972. Distribution and
abundance of young-of-the-year striped bass, Morone
saxatilis, in relation to river flow in the Sacramento-San
Joaquin Estuary. Transactions of the American Fisheries
Society 101(3):442-452.
For more information about this program element contact:
Lee Miller, California Department of Fish and Game
