Variation in Responses of Fishes across Multiple Reserves within a Network of Marine Protected Areas in Temperate Waters

March Variation in Responses of Fishes across Multiple Reserves within a Network of Marine Protected Areas in Temperate Waters Richard M. Starr 0 1 Dean E. Wendt 0 1 Cheryl L. Barnes 0 1 Corina I. Marks 0 1 Dan Malone 0 1 Grant Waltz 0 1 Katherine T. Schmidt 0 1 Jennifer Chiu 0 1 Andrea L. Launer 0 1 Nathan C. Hall 0 1 Nolle Yochum 0 1 0 1 California Sea Grant Extension Program, Moss Landing Marine Laboratories, Moss Landing, California, United States of America , 2 Moss Landing Marine Laboratories , Moss Landing, California, United States of America, 3 California Polytechnic University, San Luis Obispo, California, United States of America, 4 University of California Santa Cruz, Santa Cruz, California, United States of America, 5 Oregon State University , Corvallis, Oregon , United States of America 1 Academic Editor: Jan Geert Hiddink, Bangor University , UNITED KINGDOM Meta-analyses of field studies have shown that biomass, density, species richness, and size of organisms protected by no-take marine reserves generally increase over time. The magnitude and timing of changes in these response variables, however, vary greatly and depend upon the taxonomic groups protected, size and type of reserve, oceanographic regime, and time since the reserve was implemented. We conducted collaborative, fishery-independent surveys of fishes for seven years in and near newly created marine protected areas (MPAs) in central California, USA. Results showed that initially most MPAs contained more and larger fishes than associated reference sites, likely due to differences in habitat quality. The differences between MPAs and reference sites did not greatly change over the seven years of our study, indicating that reserve benefits will be slow to accumulate in California's temperate eastern boundary current. Fishes in an older reserve that has been closed to fishing since 1973, however, were significantly more abundant and larger than those in associated reference sites. This indicates that reserve benefits are likely to accrue in the California Current ecosystem, but that 20 years or more may be needed to detect significant changes in response variables that are due to MPA implementation. Because of the high spatial and temporal variability of fish recruitment patterns, long-term monitoring is needed to identify positive responses of fishes to protection in the diverse set of habitats in a dynamic eastern boundary current. Qualitative estimates of response variables, such as would be obtained from an expert opinion process, are unlikely to provide an accurate description of MPA performance. Similarly, using one species or one MPA as an indicator is unlikely to provide sufficient resolution to accurately describe the performance of multiple MPAs. - Funding: The authors thank the California Coastal and Marine Initiative of the Resources Legacy Fund Foundation (http://www.resourceslegacyfund.org), the California Ocean Protection Council (http://www.opc. ca.gov/), the California Sea Grant College Program (http://www-csgc.ucsd.edu, grant number 10-066 Project R/OPCFISH13B), the David and Lucile Packard Foundation (http://www.packard.org/), the Keith Campbell Foundation for the Environment (http://www.campbellfoundation.org/), FishWise (fishwise.org/), and Santa Monica Seafood (http:// www.santamonicaseafood.com) for funding this research. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The funding provided from commercial sources, along with any other relevant declarations relating to employment, consultancy, patents, products in development, marketed products, etc., does not alter the authors' adherence to PLOS ONE policies on sharing data and materials. Marine protected areas (MPAs) in general, and no-take marine reserves specifically, are increasingly being used as tools for fisheries management and conservation of marine resources around the world [1], [2]. Empirical evidence for the ecological success of marine reserves is accumulating and meta-analyses of field studies show that marine reserves typically yield positive results with respect to an increase in the response variables of biomass, density, species richness, and size of organisms protected (e.g., [36]). The magnitude and timing of changes in response variables across the world, however, varies greatly and depends upon the taxonomic groups protected, life history of species protected, size of reserve, protection level and amount of enforcement, oceanographic regime, and time since the reserve was implemented [6], [7]. This variability may be one reason why the debate continues about the value of marine reserves, especially in temperate environments [6], and provides strong rationale that monitoring is critical for the evaluation of reserves as an approach to managing marine resources [8]. Over the last ten years, the state government of California, USA, has implemented a longplanned network of MPAs. After two unsuccessful efforts to establish MPAs, a comprehensive planning process was undertaken to design networks of MPAs that were based on size and spacing guidelines designed to ensure connectivity among MPAs [9], [10]. The first set of these networks was established in central California in 2007; it contains 29 MPAs and protects a total of 529 km2 (17.9%) of nearshore habitats, with no-take marine reserves protecting 218 km2 (7.4%) of the states central coast waters [11]. The theoretical benefits of the network of MPAs include providing habitat (and therefore species) diversity and redundancy, protection against localized environmental catastrophe and climate change, maintenance of genetic diversity, population persistence, and distribution of costs and benefits with respect to fisheries. The state law that led to the formation of the new MPAs contained six specific goals [11]. Two of these goals related to the long-term benefits that are intended to accrue from increased resource protection are: 1) to protect the natural diversity and abundance of marine life and the structure, function, and integrity of marine ecosystems, and 2) to help sustain, conserve, and protect marine life populations, including those of economic value, and rebuild those that are depleted. An additional long-term goal is: 3) to ensure that the states MPAs are designed and managed, to the extent possible, as a network. The other three goals relate to recreation, education, intrinsic social values, and governance issues. Inherent in the development of the goals was the expectation to monitor and adaptively manage MPAs. The state of California is now developing metrics that can be used to monitor, evaluate, and adaptively manage MPAs with respect to those predicted benefits. The focus of the three adopted goals relating to marine populations is on maintenance of biodiversity and population persistence. Monitoring projects that provide data for ad (...truncated)