Baseline characterization of nearshore Rocky reef fishes found in northern California marine protected areas

The nearshore rocky reef habitat along California’s North Coast supports a diverse assemblage of ecologically, economically, and culturally important fishes. In December 2012, a network of Marine Protected Areas (MPAs) was established in Northern California with the goal of protecting these species. Our study utilized collaborative hook and line fishing methods, while employing local charter fishing vessels, to establish a baseline of rocky reef fishes associated with four MPAs and four unprotected reference sites. These baseline data were then used to inform generalized additive models (GAMs) to explore potential drivers of relative abundance, size, and diversity of fishes. Understanding what factors drive initial conditions in paired sites will allow managers to track fluctuations in fish communities associated with rocky reefs, and properly attribute changes to MPA effects over time. This is especially important in the Pyramid Point and Sea Lion Gulch MPAs, where catch per unity effort was significantly different from their associated reference sites. These differences are likely a function of different levels of historical fishing pressure between MPAs and reference sites. Distance from port, a proxy for historical fishing pressure, and depth, were the most important predictors of fish catch per unit effort and diversity in the North Coast MPA Region. Continued monitoring of MPAs in the North Coast region will be critical in the evaluation of MPA effects and provide much needed fishery-independent data that can be used to improve management strategies in this area