Final Report for Use of Estuarine, Intertidal, and Subtidal Habitats by Seabirds Within the MLPA South Coast Study Region

Seabirds are long-lived, upper trophic level predators that are integral components of marine ecosystems. During the breeding season, seabirds are central place foragers and must return to their nests to incubate eggs and provision young throughout the day. As such, they have limited foraging ranges during that time and will benefit from protected areas within these ranges. Marine protected areas (MPAs) can provide both direct and indirect benefits to seabirds. Direct benefits involve reducing the direct interactions seabirds have with humans like incidental take and gear entanglement as well as human- caused disturbance to breeding and roosting sites. Indirect benefits involve reducing competition with humans for prey resources. Many coastally breeding seabirds rely on juvenile age classes of fished species. Decreases in adult fish catch can lead to increased spawning biomass and, thus, more seabird prey. Herein, we summarize the results of baseline seabird monitoring within the South Coast Study Region (SCSR) of California’s Marine Life Protection Act (MLPA) Initiative in 2012-2013. The long-term objectives of our monitoring are to 1) document how seabirds are using coastal and nearshore habitats in relation to newly established MPAs and 2) develop seabirds as indicators to study the processes (e.g., recruitment) impacting change resulting from MPA establishment, including changes in nearshore fish and invertebrate populations and human use patterns that can impact seabirds.