The South Coast Study Region (SCSR) encompasses a broad section of southern California including both mainland and island coastal regions. The exceptionally high diversity of marine life in this region is largely due to the mixing of several major oceanographic current systems, and the region is characterized by strong gradients in environmental conditions. Rocky shores characterize approximately 26.83% of the SCSR, and in many areas attract a large number of individuals who frequent the intertidal zone for recreation, education, and for collecting flora and fauna for food, fish bait, or decoration. Rocky intertidal ecosystems are one of the most heavily human-‐impacted ecosystems along the mainland southern California coast (in addition to sandy beaches) due to their ease of access, and has made them particularly vulnerable to the negative effects of human activities resulting from both extraction (harvesting and collecting) as well as physicaldisturbance (trampling, overturning and handling).

We systematically surveyed 94 of the 122 nearshore rocky reefs in the California south coast study region (SCSR). This synoptic baseline survey was conducted at 75 individual sites in 2011 and 88 sites in 2012. In addition, we incorporate two similar ‘historical’ data sets from 59 sites in 2004 and 79 sites in 2008. From 2011-2012, we surveyed all accessible nearshore rocky reefs found in the SCSR MPAs and determined the appropriateness of references areas for each. This baseline provides, for the first time, a taxonomically exhaustive biogeographic assessment of the nearshore subtidal reefs in the SCSR, improving significantly on our knowledge of the region and incorporating newly established and existing MPAs. Results confirm previously described patterns for subtidal fishes, reflect the physical oceanographic complexities of the Southern California Bight and add new knowledge to biogeographic patterns of algae and invertebrates. The SCSR is characterized by strong environmental gradients, a major defining feature of the SCSR compared to the other California MLPA Study Regions that have relatively more spatially consistent physical environments. These differences are reflected biologically in a high degree of kelp forest community structure across the region. We identified 17 geographically cohesive community clusters, each with distinct fish, invertebrate, and algal assemblages (Figure ES.1). Although kelp forest communities in the SCSR are highly variable, the structure can be related to the sea surface temperature patterns caused by the confluence of the California Current, the Southern California Counter Current and localized upwelling. Benthic habitat structure also varies within the region; the geology and structure of island reefs are functionally different from mainland reefs. Mainland reefs generally are less steep, can be found significantly offshore of the coastline, and have a greater influence of sedimentation moving through the system. With few exceptions, island reefs are generally abrupt, high relief structures, tightly fit to the coastline with less influence of the nearby soft bottom habitat. Ideally, long-term monitoring of MPAs should be distributed across the distinct areas as each is likely to respond differently.

Marine Applied Research and Exploration (MARE) preformed quantitative baseline surveys within the NCSR in 2014 and 2015 with the overall goal to describe the condition of three distinctive priority ecosystem features within four MPAs and their adjacent reference study areas: a) mid-depth rock ecosystems, b) softbottom subtidal ecosystems, and c) deep ecosystems (including canyons). Long-term monitoring trends within these habitats will be compared to baseline conditions, assisting in evaluating MPA effectiveness. The four MPAs chosen for evaluation include: Point St. George Reef Offshore SMCA, Reading Rock State Marine Reserve, Mattole Canyon State Marine Reserve and Ten Mile State Marine Reserve. Outside reference areas with similar habitats and depths were also surveyed for comparison. During the first two years following implementation, benthic visual surveys were conducted using a remotely operated vehicle (ROV) to assess initial changes in fishes, macro-invertebrates and associated seafloor habitats. The ROV collected video and still imagery while moving along a fixed path (transect) along the sea floor. Video imagery collected was analyzed to characterize substrate, habitat types, habitat complexity (rugosity), and estimate finfish and macro-invertebrate distribution, relative abundance and density. In total, 60 ROV dives were completed surveying more than 106 km (19 ha) between 13 and 421 m deep. In addition, over 16,500 still photos were taken.

The objectives of this baseline study of rocky intertidal habitats along the North Coast Study Region (NCSR) are to (1) produce a quantitative baseline characterization of the structure of rocky intertidal ecosystems in Marine Protected Areas (MPAs) established by the Marine Life Protection Act (MLPA), (2) provide an initial comparison between rocky intertidal ecosystems inside MPAs and nearby associated (unprotected) reference areas, (3) analytically explore baseline characterizations for potential indicators of the state of rocky intertidal ecosystems, (4) generate a fish biodiversity baseline within rocky tide pools at a few sites inside and outside of MPAs (for the first time) as well as (5) examine rockfish recruitment into these tide pools, and (6) integrate these assessments with other components of the baseline survey, including (7) high resolution topographic geological surveys, to inform the role and design of these programs for future monitoring and evaluation of MPAs.