Rapid Effects of Marine Reserves via Larval Dispersal

School of Natural Resources, University of Arizona, Tucson, Arizona, United States of America.
PLoS ONE (Impact Factor: 3.23). 02/2009; 4(1):e4140. DOI: 10.1371/journal.pone.0004140
Source: PubMed


Marine reserves have been advocated worldwide as conservation and fishery management tools. It is argued that they can protect ecosystems and also benefit fisheries via density-dependent spillover of adults and enhanced larval dispersal into fishing areas. However, while evidence has shown that marine reserves can meet conservation targets, their effects on fisheries are less understood. In particular, the basic question of if and over what temporal and spatial scales reserves can benefit fished populations via larval dispersal remains unanswered. We tested predictions of a larval transport model for a marine reserve network in the Gulf of California, Mexico, via field oceanography and repeated density counts of recently settled juvenile commercial mollusks before and after reserve establishment. We show that local retention of larvae within a reserve network can take place with enhanced, but spatially-explicit, recruitment to local fisheries. Enhancement occurred rapidly (2 yrs), with up to a three-fold increase in density of juveniles found in fished areas at the downstream edge of the reserve network, but other fishing areas within the network were unaffected. These findings were consistent with our model predictions. Our findings underscore the potential benefits of protecting larval sources and show that enhancement in recruitment can be manifested rapidly. However, benefits can be markedly variable within a local seascape. Hence, effects of marine reserve networks, positive or negative, may be overlooked when only focusing on overall responses and not considering finer spatially-explicit responses within a reserve network and its adjacent fishing grounds. Our results therefore call for future research on marine reserves that addresses this variability in order to help frame appropriate scenarios for the spatial management scales of interest.

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Available from: Richard Cudney-Bueno,
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    • "As a fisheries tool, no-take marine reserves can protect and restore marine fisheries through an increase in biomass, age, and density of protected species inside the reserve, leading to an increase in the reproductive potential of these species due to lower mortality from the prohibition on harvesting. This increase in density and reproduction can lead to density-dependent dispersal of juvenile and adults ( " spillover " ) and export of larvae and eggs across reserve borders to the surrounding fished areas (Gell & Roberts 2003, Cudney-Bueno et al. 2009, Goñi et al. 2010), though the effectiveness can be variable based on, for example, prevailing currents, reproductive timing, or larval duration of target species (Cudney-Bueno et al. 2009, Carson et al. 2010, Cole et al. 2010). By supplying the nonprotected areas with recruits through " spillover " of juveniles and adults and export of eggs and larvae, the fishery can be replenished and maintained. "
    Caribbean Journal of Science 01/2014; 48:18-30. · 0.35 Impact Factor
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    • "Readily-available biological and oceanographic data (e.g. satellite-derived data on spatial variability of high-productivity areas) (Hidalgo-González and Alvarez-Borrego, 2011), combined with existing oceanographic-ecological models (Marinone et al., 2008; Cudney-Bueno et al., 2009), can help to improve planning for processes in the Gulf of California and elsewhere. "
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    ABSTRACT: 1.Overfishing, pollution, coastal development and climate change threaten marine biodiversity globally and compromise the services that marine ecosystems provide. Systematic conservation planning (SCP) provides a framework to identify areas where actions can be effective in addressing these threats, while minimizing the costs of interventions. This study investigated the application of SCP in the Gulf of California, a marine hotspot where seven prioritization exercises have been undertaken. 2.The review of planning exercises showed that the use of SCP methods has progressed slowly (gaps include planning for land–sea connections and ecosystem services) and highlighted benefits and difficulties of applying SCP principles and tools. 3.Despite some convergence, important spatial differences were found in priorities between plans. Convergence was evident in well-studied shallow and benthic marine ecosystems. There were also important differences related to the planning approach, methods and extent. Divergence between methodological and spatial similarities between plans suggests that additional factors (e.g. manually delineating priority areas, incorporating updated datasets, random error), in addition to data and objectives, play an important role in defining the distribution of conservation priorities. 4.According to expert opinion, the implementation of new marine protected areas (MPAs) in the region has been influenced by some of the planning exercises. However, uptake of planning outputs has progressed slowly for many reasons (e.g. conflicting mandates and interests between organizations, limited technical capacities and resources, insufficient political commitment). Other benefits of planning included: developing institutional skills and knowledge; improving collaboration and coordination between organizations (including agencies, and local, regional and national NGOs); converging on the need to assess priorities for marine conservation in regional context; and building trust among organizations. 5.The existence of multiple marine conservation plans in the Gulf of California also highlighted some of the complexities and benefits of having multiple sets of priorities.
    Aquatic Conservation Marine and Freshwater Ecosystems 08/2013; 23(4). DOI:10.1002/aqc.2334 · 2.14 Impact Factor
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    • "This sub-tropical enclosed sea contains high biodiversity and endemism [3], hosts a human population that is highly dependent on the ocean for income and food security, and has minimal resources for monitoring and enforcement [4]. Mexico has achieved notable successes in establishing EBM policy with marine protected areas (MPAs) [5] [6] and fishing concessions or exclusive rights with locally-designed access and use controls [7] [8]. However, as a result of an inadequate policy framework and insufficient surveillance and enforcement, most fisheries still operate as open access and many are overexploited [9] [10]. "
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    ABSTRACT: The Northern Gulf of California is an area important for small-scale fisheries in terms of economic activity and food security, but widespread non-compliance with fisheries regulations impedes effective management of resources and conservation efforts. Where a previous study evaluated quantitatively a theoretical situation in which all regulations are perfectly followed, this article compares a suite of recently proposed ecosystem-based management (EBM) policies against the expected benefits of full enforcement of current regulations. Policies evaluated include no-take marine protected areas (MPAs), breeding period closures, changes in hook size and fishing effort, and gear-specific spatial closures. No-take MPAs yield ecological benefits over a wide range of MPA sizes and characteristics, but do not increase overall catch. Seasonal closures are effective at reducing overfishing for the depleted leopard grouper (Mycteroperca rosacea); changing the hook size of artisanal longlines does not increase catch of either the target species or the assemblage, and gear-specific fishery closures for crab traps near Puerto Peñasco are effective at reducing overfishing of blue crab (Callinectes bellicosus and C. arcuatus). In general, full enforcement of existing regulations outperforms these EBM policies in terms of conservation benefits, but it may be less palatable to stakeholders as it requires major reductions in catch.
    Marine Policy 11/2012; 36(6):1275–1283. DOI:10.1016/j.marpol.2012.03.016 · 2.62 Impact Factor
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