Publication Date:
2021-06-26
Description:
The 1989-90 spawning biomass estimate of Pacific herring,Clupea pallasi, from spawning-ground surveys in SanFrancisco Bay was 71,000 tons, a 5,000 ton increase over the 1988-89 biomass estimate of 66,000 tons. The San Francisco Bay herring biomass has been on an upward cycle since 1984, and results from spawning-ground surveys indicated that the population was at its highest level in eight years.In Tomales Bay the 1989-90 herring spawning biomass estimate was 345 tons. This was the third consecutive poor season. Herring have nearly abandoned Tomales Bay, and reduced freshwater in flows due to the current drought condition in California were the probable cause for the change in spawning behavior.An additional 445 tons were found in Bodega Bay byhydroacoustic surveys. The total herring biomass estimatefor Tomales-Bodega area was 790 tons.January was the month of peak spawning activity in SanFrancisco Bay, with 30,000 tons of herring spawning duringthe month. In Tomales there was only one spawning run; itoccurred on January 31, 1990.In San Francisco Bay, 67% of all spawning occurred along the San Francisco waterfront, and only 6% of all spawningactivity was in the northern part of the bay. No spawningwas found near Tiburon, Belvedere, Richmond, Berkeley,Candlestick Point, Sierra Point, Oyster Point, or CoyotePoint.A total of 3.5 million m2 of eelgrass, Zoster marina, wasmeasured in Tomales Bay this season, a decline of about10% over the past two seasons.Eelgrass density kg/m2 did not change significantly thisseason. (34pp.)
Keywords:
Ecology
;
Fisheries
;
Biology
;
Pacific herring
;
Clupea pallasi
;
California
;
Tomales Bay
;
San Francisco Bay
;
California
Repository Name:
AquaDocs
Type:
monograph
Format:
application/pdf
Format:
application/pdf
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