LARVAL FISH ASSEMBLAGES OF THE CALIFORNIA CURRENT REGION AND THEIR HORIZONTAL AND VERTICAL DISTRIBUTIONS ACROSS A FRONT

Cruises of the California Cooperative Oceanic Fisheries Investigations occupied 31,214 survey stations in a one million km(2) area off California and Baja California during 1951 to 1984. Recurrent group analysis of 249 larval fish taxa placed 36 taxa in 12 recurrent groups. These groups reflect the oceanographic complexity of the region with Subarctic-Transitional, Eastern Tropical Pacific (ETP), and Central Water Mass components. The major shorefish recurrent group is associated with the large shelf area of Sebastian Viscaino Bay off central Baja California. Cluster analysis using correlation coefficients of abundance as the measure of distance and principal component analysis produced groupings that agreed in general with groups formed by presence-absence analysis. Environmental effects on these groups were studied by examining changes in horizontal and vertical distribution across a frontal region. Plankton samples from the FRONTS 85 cruise conducted in July, 1985, southwest of the Southern California Bight, allowed us to investigate the fine scale distribution of assemblages across a semi-permanent frontal zone separating cold eutrophic water to the north from relatively warm, oligotrophic water to the south. Ichthyoplankton samples from a 120-n. mi. transect across the front, including 42 oblique bongo tows and 8 MOCNESS tows to 1,000 m, demonstrated: 1) the transition between Subarctic-Transitional and ETP/Central Water Mass species, and 2) distinctly different patterns of vertical distribution for the same species at the north and south sides of the front.