Description
Summary:Seabirds are long-lived, upper trophic level predators that are integral components of marine ecosystems. Marine protected areas (MPAs) can provide both direct and indirect benefits to seabirds. Direct benefits involve reducing the direct interactions seabirds have with humans such as from fisheries and recreational activities. Indirect benefits involve reducing competition with humans for prey resources. As the abundance of prey increases within and adjacent to MPAs, seabirds may benefit as more abundant prey resources lead to increases in their productivity and population sizes. We monitored the populations of six coastally breeding marine bird species: four seabirds that feed largely on juvenile and other small fishes in nearshore habitats (Brandt’s cormorant, pelagic cormorant, double-crested cormorant, and pigeon guillemot), one seabird that feeds on both fish and intertidal invertebrates (western gull), and one shorebird that feeds primarily on rocky intertidal invertebrates (black oystercatcher). We collected data on baseline population size, productivity, foraging rates, and rates of human-caused disturbance inside and outside of three MPA clusters: Pyramid Point SMCA (Del Norte county); South Cape Mendocino SMR (Humboldt County); and Ten Mile SMR, MacKerricher SMCA, Point Cabrillo SMR, and Russian Gulch SMCA (Mendocino county). The long-term objectives of our monitoring are to 1) document how seabirds are using coastal and nearshore habitats in relation to a sample of newly established MPAs within the NCSR and 2) develop seabirds as tools to investigate changes in fish and invertebrate populations inside and outside of NCSR MPAs. Data presented here focus on baseline disturbance monitoring for both roosting and breeding seabirds as well as hauled out marine mammals.