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Primary production and the anchovy population in the Southern California Bight: Comparison of time series 1
Author(s) -
Smith Paul E.,
Eppley Richard W.
Publication year - 1982
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1982.27.1.0001
Subject(s) - anchovy , zooplankton , trophic level , environmental science , fishery , bay , biomass (ecology) , oceanography , abundance (ecology) , seasonality , ecology , biology , geology , fish <actinopterygii>
Two new time series for the Southern California Bight are presented: anchovy biomass, 1951–1979, and primary production, estimated for the years 1920–1979 from 15 cruises conducted between 1974 and 1979. Annual and longer term averages show little relationship to each other except that values for both were low in the climatically warm water years 1957– 1958. The primary production time series is similar to two existing time series: CalCOFI zooplankton in the bight and microplankton in Santa Monica Bay, 1951–1966. Thus estimated primary production does reflect the carrying capacity of these waters for lower trophic level consumers. Seasonal averages of anchovy larvae are highest in the winter and spring quarters when primary production is increasing. Interannual variation was pronounced in both seasonal average primary production and seasonal average abundance of anchovy larvae. About 50% of the variation in number of anchovy larvae was explained by variation in primary production in the same quarter and zooplankton standing stock three quarters earlier. In 1966, the year of maximum anchovy abundance, the energy expended in anchovy egg production was equivalent to about 1.8% of primary production. The anchovy ration was about 18% of primary production. The ratio of zooplankton biomass to primary production was highest in years when anchovy biomass was greatest.