DISTRIBUTION OF LARVAL PACIFIC SARDINE, SARDlNOPS SAGAX, IN SHALLOW COASTAL WATERS BETWEEN OCEANSIDE AND SAN ONOFRE, CALIFORNIA: 1978-1986

ABSTRACF Spatial and temporal distributions of larval Pacific sardine, Sardinops sagax, were investigated at two nearshore sites between San Onofre and Oceanside, California. Neuston, midwater, and epibenthic samples were collected at night with plankton nets towed at a randomly selected isobath within each of five sampling blocks between the 6-m and 75-m isobaths at each site. The San Onofre site was sampled from January 1978 through September 1986; the site near Oceanside was sampled from July 1979 through September 1986. Sampling frequency varied from weekly to quarterly, depending on other requirements of the study. The average cross-shelf distribution of larvae differed little from year to year: abundance usually was highest between the 12-m and 45-m isobaths, particularly for yolk-sac and preflexion larvae. Densities were typically highest in midwater. Vertical and cross-shelf distributions were similar at both study sites. Larvae were found nearly year-round, but were most abundant in summer and fall. Seasonal abundance patterns differed relatively little between sites or from year to year. Abundance was quite low from 1978 to 1980, then increased dramatically to a peak in 1984. The results ofthis study, together with other published reports, suggest that the resurgence of the Pacific sardine off southern California in the early 1980s began in 1981 in shallow waters along the central southem California coast.

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