| Variability of upwelling, coupled with larger scale processes (El Nino/La Nina), affects productivity and the distribution of fish and marine mammals. Marine mammal and environmental data gathered using standard strip transect methodology were used with CTD and mid-water trawl data collected off central California from Bodega Bay to Monterey Bay 1986--1999 (except 1995--96). Distributional patterns of marine mammals relative to hydrography were investigated using Geographical Information System, Percent Similarity Index (PSI), multiple logistic regression, and principal component analyses. Differences in species composition and presence/absence of marine mammals likely were related to significant differences in ocean structure resulting from local and large-scale processes. Distribution of the dominant species (California sea lion, northern fur seal, Pacific white-sided dolphin, Dall's porpoise, harbor porpoise, and humpback whale) was related to bathymetry and changing oceanographic and biological conditions that affected their prey. |
