Final technical report - Baseline characterization of newly established marine protected areas within the North Central California study region - seabird colony and foraging studies

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 North Central Coast Study Region (NCCSR) of California’s Marine Life Protection Act (MLPA) Initiative in 2010-2012. 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 in nearshore fish and invertebrate populations and human use patterns that can impact seabirds.

海鸟为长寿的顶级营养级捕食者，是海洋生态系统不可或缺的组成部分。繁殖季期间，海鸟属于中心地觅食者，每日必须返回巢穴孵卵并育雏。因此，该时段内其觅食范围受限，在此范围内的保护区域将为其带来益处。海洋保护区（Marine Protected Areas, MPAs）可为海鸟提供直接与间接双重益处：直接益处包括减少海鸟与人类的直接交互，例如误捕、渔具缠绕，以及人类对海鸟繁殖与栖息场所造成的干扰；间接益处则包括降低海鸟与人类在猎物资源上的竞争。许多沿海繁殖的海鸟依赖捕捞物种的幼龄个体作为食物来源，成鱼捕捞量的下降可提升产卵种群生物量，进而为海鸟提供更多猎物。本研究总结了2010-2012年间，加利福尼亚州《海洋生命保护法》（Marine Life Protection Act, MLPA）倡议框架下北中海岸研究区（North Central Coast Study Region, NCCSR）内的海鸟基线监测结果。本次监测的长期目标有二：其一，厘清海鸟如何利用新建海洋保护区周边的沿海与近岸生境；其二，以海鸟作为指示物种，研究海洋保护区设立引发的变化背后的相关过程（例如种群补充），其中包括近岸鱼类与无脊椎动物种群变化，以及可能影响海鸟的人类活动模式变化。