Published in California Cooperative Oceanic Fisheries Investigations Reports, Volume 49, January 1, 2008, pages 241-255. This article was published online at California Cooperative Oceanic Fisheries Investigations.
Many nearshore rockfish species have small homerange sizes and therefore may be affected by heavier localized fishing in nearport areas. For this study we examined longterm trends in rockfish and lingcod landings from the commercial passenger fishing vessel (CPFV) fishery along the south central coast (SCC) of California using data from two sources: California Department of Fish and Game (CDFG) surveys from 1988–98 and California Polytechnic State University (Cal Poly) surveys in 2003–04. The objective was to make comparisons between areas close to port (that receive greater fishing effort) and those far from port (areas receiving less fishing effort). We analyzed parameters for individual species and species assemblage composition to determine if these parameters are effective at detecting changes on a species specific and a multispecies level for this region and what their applications are towards newly established Marine Protected Areas (MPAs) along the SCC.
A multivariate approach using nonstandardized Bray Curtis similarities effectively detected both spatial and temporal changes within and between fish assemblages for areas along the SCC. For individual species, catches of some species yielded larger individuals farther from port, while catch per unit effort (CPUE) for most species did not differ between nearport and distantport areas over time. Trends were easier to detect for species that exclusively inhabit shallower waters and suggest that these may be better indicator species for examining the effectiveness of MPAs. Results were difficult to interpret for species that occur at mixed depths since some migrate to deeper waters when they mature, whereas others inhabit both shallow and deep depths as adults.