ENVIRONMENTAL INFLUENCES ON SPECIES COMPOSITION OF THE COMMERCIAL HARVEST OF FINFISH AND INVERTEBRATES OFF CALIFORNIA

California commercial finfish and invertebrate landings from catches made in waters off California were examined to evaluate the relationship of fluctuations in species composition to environmental influences during 1930-2000. We considered empirical orthogonal function (EOF) analysis on log(e)-transformed annual weight for species and species groups. We developed ocean process indexes by accumulating monthly anomalies of central California sea surface temperature (SST) and southward wind stress (SWS), SST from La Jolla, California, and the Pacific Decadal Oscillation (PDO). Time variation of the first EOF, which explains more than 25% of the variance, is significantly correlated with the LaJolla SST and the PDO indexes. Time variation of the second EOF, which accounts for 20% of the variance, is significantly correlated with the SWS index, and its variability is similar to concurrent ecosystem changes. Individual landings series were not adjusted for fishing effort, so we estimated annual effort using the number of boats in the fishery as a proxy. Correlation of the species composition to the effort proxy and to inflation-adjusted total ex-vessel value indicates that fishery factors have acted together with environmental events and fisheries management regulations to produce nearly continuous change in the species composition of commercial finfish and invertebrate landings from 1930 to 2000.