Distance from a Fishing Community Explains Fish Abundance in a No-Take Zone with Weak Compliance

There are numerous examples of no-take marine reserves effectively conserving fish stocks within their boundaries. However, no-take reserves can be rendered ineffective and turned into ‘paper parks’ through poor compliance and weak enforcement of reserve regulations. Long-term monitoring is thus essential to assess the effectiveness of marine reserves in meeting conservation and management objectives. This study documents the present state of the 15-year old no-take zone (NTZ) of South El Ghargana within the Nabq Managed Resource Protected Area, South Sinai, Egyptian Red Sea. Previous studies credited willing compliance by the local fishing community for the increased abundances of targeted fish within the designated NTZ boundaries compared to adjacent fished or take-zones. We compared benthic habitat and fish abundance within the NTZ and the adjacent take sites open to fishing, but found no significant effect of the reserve. Instead, the strongest evidence was for a simple negative relationship between fishing pressure and distance from the closest fishing village. The abundance of targeted piscivorous fish increased significantly with increasing distance from the village, while herbivorous fish showed the opposite trend. This gradient was supported by a corresponding negative correlation between the amount of discarded fishing gear observed on the reef and increasing distance from the village. Discarded fishing gear within the NTZ suggested decreased compliance with the no-take regulations. Our findings indicate that due to non-compliance the no-take reserve is no longer functioning effectively, despite its apparent initial successes and instead a gradient of fishing pressure exists with distance from the nearest fishing community.     

Marine reserves: size and age do matter

Marine reserves are widely used throughout the world to prevent overfishing and conserve biodiversity, but uncertainties remain about their optimal design. The effects of marine reserves are heterogeneous. Despite theoretical findings, empirical studies have previously found no effect of size on the effectiveness of marine reserves in protecting commercial fish stocks. Using 58 datasets from 19 European marine reserves, we show that reserve size and age do matter: Increasing the size of the no-take zone increases the density of commercial fishes within the reserve compared with outside; whereas the size of the buffer zone has the opposite effect. Moreover, positive effects of marine reserve on commercial fish species and species richness are linked to the time elapsed since the establishment of the protection scheme. The reserve size-dependency of the response to protection has strong implications for the spatial management of coastal areas because marine reserves are used for spatial zoning.     

Effects of marine reserve characteristics on the protection of fish populations: a meta-analysis

Meta-analyses of published data for 19 marine reserves reveal that marine protected areas enhance species richness consistently, but their effect on fish abundance is more variable. Overall, there was a slight (11%) but significant increase in fish species number inside marine reserves, with all reserves sharing a common effect. There was a substantial but non-significant increase in overall fish abundance inside marine reserves compared to adjacent, non-reserve areas. When only species that are the target of fisheries were considered, fish abundance was significantly higher (by 28%) within reserve boundaries. Marine reserves vary significantly in the extent and direction of their response. This variability in relative abundance was not attributable to differences in survey methodology among studies, nor correlated with reserve characteristics such as reserve area, years since protection, latitude nor species diversity. The effectiveness of marine reserves in enhancing fish abundance may be largely related to the intensity of exploitation outside reserve boundaries and to the composition of the fish community within boundaries. It is recommended that studies of marine reserve effectiveness should routinely report fishing intensity, effectiveness of enforcement and habitat characteristics.     

Rapid Effects of Marine Reserves via Larval Dispersal

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.     

Go with the flow: tidal import and export of larvae from semi-enclosed bays

There is a growing body of evidence that suggests the effective functioning of marine reserves is dependent on the dispersal and recruitment of larvae. Enhanced production inside reserves is predicted to lead to a net larval export and increased settlement and recruitment outside reserve boundaries. However, larval retention in bays is also well documented. Since bays are increasingly being used as reserve areas, planktonic larvae of benthic marine invertebrates were sampled from two semi-enclosed marine reserves during flood and ebb tides to determine whether these bays are acting as net exporters of larvae. Neither reserve was a net importer or exporter of species richness, larval abundance or diversity, although one reserve showed a small export of species richness during the hours of darkness. Both reserves balanced the net import of some species with a net export of others, which was generally related to adult or larval abundance, although exceptions were found in one reserve. Significant effects of light were found, with the net import or export of some species occurring exclusively during either the hours of daylight or darkness. An increased understanding of larval sink-source dynamics in bays is essential for ensuring their effective use as marine reserves to meet specific conservation needs. Guest editors: J. Davenport, G. Burnell, T. Cross, M. Emmerson, R. McAllen, R. Ramsay & E. Rogan Challenges to Marine Ecosystems     

Trajectories and magnitude of change in coral reef fish populations in Philippine marine reserves: a meta-analysis

Marine reserves are widely implemented worldwide to meet both conservation and fisheries management goals. This study examines the efficacy of Philippine marine reserves using meta-analysis by comparing variations in fish density (1) between reserves and adjacent fished reefs (spatial comparison), (2) within reserves before establishment relative to years following the establishment (temporal comparison), and (3) among reserves classified based on size, age, and enforcement capacity. A grand (total) mean of nineteen 22.3 ha coral reef reserves, protected for a mean duration of 8.2 years, were included in the meta-analyses. The overall density of fishes was higher in the reserves compared with the fished reefs and this difference was largely accounted for by exploited fishes. However, the overall density of fishes within the same reserves remained similar from the period before its establishment to several years following its establishment. Only the density of nonexploited fishes increased significantly during years subsequent to the establishment of the reserves. Neither age nor size of reserves correlated with pattern of change in fish density following the establishment of the reserves; however, fish density was consistently higher in larger and older reserves relative to smaller and younger reserves in the spatial comparison. Furthermore, well-enforced reserves had higher density of exploited fishes relative to less-enforced reserves in both spatial and temporal comparisons. In general, the magnitude and trajectory of change in fish density following the establishment of Philippine marine reserves are influenced by (1) functional groups of fishes under consideration, (2) size and age of the reserve, and (3) level of enforcement of the regulatory mechanisms necessary to sustain a marine reserve.     

Larval export from marine reserves and the recruitment benefit for fish and fisheries

Marine reserves, areas closed to all forms of fishing, continue to be advocated and implemented to supplement fisheries and conserve populations. However, although the reproductive potential of important fishery species can dramatically increase inside reserves, the extent to which larval offspring are exported and the relative contribution of reserves to recruitment in fished and protected populations are unknown. Using genetic parentage analyses, we resolve patterns of larval dispersal for two species of exploited coral reef fish within a network of marine reserves on the Great Barrier Reef. In a 1,000 km(2) study area, populations resident in three reserves exported 83% (coral trout, Plectropomus maculatus) and 55% (stripey snapper, Lutjanus carponotatus) of assigned offspring to fished reefs, with the remainder having recruited to natal reserves or other reserves in the region. We estimate that reserves, which account for just 28% of the local reef area, produced approximately half of all juvenile recruitment to both reserve and fished reefs within 30 km. Our results provide compelling evidence that adequately protected reserve networks can make a significant contribution to the replenishment of populations on both reserve and fished reefs at a scale that benefits local stakeholders.     

Reserves as tools for alleviating impacts of marine disease

Marine protected areas can prevent over-exploitation, but their effect on marine diseases is less clear. We examined how marine reserves can reduce diseases affecting reef-building corals following acute and chronic disturbances. One year after a severe tropical cyclone, corals inside reserves had sevenfold lower levels of disease than those in non-reserves. Similarly, disease prevalence was threefold lower on reserve reefs following chronic exposure to terrestrial run-off from a degraded river catchment, when exposure duration was below the long-term site average. Examination of 35 predictor variables indicated that lower levels of derelict fishing line and injured corals inside reserves were correlated with lower levels of coral disease in both case studies, signifying that successful disease mitigation occurs when activities that damage reefs are restricted. Conversely, reserves were ineffective in moderating disease when sites were exposed to higher than average levels of run-off, demonstrating that reductions in water quality undermine resilience afforded by reserve protection. In addition to implementing protected areas, we highlight that disease management efforts should also target improving water quality and limiting anthropogenic activities that cause injury.     

Application of marine reserves to reef fisheries management

Abstract Establishing permanent ‘no-take’ marine reserves, areas where fishing and all other extractive activities are prohibited, is an attractive but under-utilized tool for fisheries management. Marine reserves could potentially deal with many fishery problems that are not effectively addressed by other traditional management measures; they also offer numerous social, economic, and scientific benefits not directly related to fisheries. Limited but growing research has shown beneficial biological and economic effects of marine reserves on fisheries. More research is needed, especially at larger scales, to determine the ideal marine reserve size, number and location necessary to optimize fisheries productivity and resource conservation. Sufficient evidence is available to justify the expanded use of marine reserves in an adaptive approach to fisheries management.     

On the Optimal Size of Marine Reserves

The excessive and unsustainable exploitation of our marine resources has led to the promotion of marine reserves as a fisheries management tool. Marine reserves, areas in which fishing is restricted or prohibited, can offer opportunities for the recovery of exploited stock and fishery enhancement. This study examines the impact of the creation of marine protected areas, from both economic and biological perspectives. The consequences of reserve establishment on the long-run equilibrium fish biomass and fishery catch levels are evaluated. We include reserve size as control variable to maximize catch at equilibrium. A continuous time model is used to simulate the effects of reserve size on fishing catch. Fish movements between the sites is assumed to take place at a faster time scale than the variation of the stock and the change of the fleet size. We take advantage of these two time scales to derive a reduced model governing the dynamics of the total fish stock and the fishing effort. Simulation results suggest that the establishment of a protected marine reserve will always lead to an increase in total fish biomass, an optimal size of a marine reserve can achieve to maximize the catch at equilibrium.     

Evidence of artisanal fishing impacts and depth refuge in assemblages of Fijian reef fish

Protection from fishing generally results in an increase in the abundance and biomass of species targeted by fisheries within marine reserve boundaries. Natural refuges such as depth may also protect such species, yet few studies in the Indo Pacific have investigated the effects of depth concomitant with marine reserves. We studied the effects of artisanal fishing and depth on reef fish assemblages in the Kubulau District of Vanua Levu Island, Fiji, using baited remote underwater stereo-video systems. Video samples were collected from shallow (5–8 m) and deep (25–30 m) sites inside and outside of a large old marine reserve (60.6 km², 13 years old) and a small new marine reserve (4.25 km², 4 years old). Species richness tended to be greater in the shallow waters of the large old reserve when compared to fished areas. In the deeper waters, species richness appeared to be comparable. The difference in shallow waters was driven by species targeted by fisheries, indicative of a depth refuge effect. In contrast, differences in the abundance composition of the fish assemblage existed between protected and fished areas for deep sites, but not shallow. Fish species targeted by local fisheries were 89% more abundant inside the large old reserve than surrounding fished areas, while non-targeted species were comparable. We observed no difference in the species richness or abundance of species targeted by fisheries inside and outside of the small new reserve. This study suggests that artisanal fishing impacts on the abundance and species richness of coral reef fish assemblages and effects of protection are more apparent with large reserves that have been established for a long period of time. Observed effects of protection also vary with depth, highlighting the importance of explicitly incorporating multiple depth strata in studies of marine reserves.     

Performance of non-native species within marine reserves

Conservation of biodiversity is a major aim of marine reserves; however the effects of reserves on non-native species, a major threat to biodiversity globally, is not widely known. Marine reserves could resist non-native species due to enhanced native diversity and biomass that heightens biotic resistance. Or non-native species could be enhanced by reserves by at least three mechanisms, including protection from harvesting, increased fishing pressure outside reserves facilitating invasions at a regional scale and increasing the exposure of reserves to more potential invaders, and increased propagule pressure from human visitation. We exhaustively searched the literature and found 13 cases that contained quantitative data on non-native species inside and outside marine reserves. In no cases did reserves resist non-native species. Of the seven cases where reserves were established prior to the arrival of the non-native species, five had no effect on the non-native species and two enhanced non-native species. Of the six cases where reserves were established in areas that had pre-existing non-native species, two had no effect on the non-native species and four enhanced the non-native species. These results suggest that while non-native species do equally well or better within marine reserves, too few data are currently available to draw broad, general conclusions regarding the effects of marine reserves on non-native species. Management plans for marine reserves rarely include guidelines for preventing or managing non-native species. If the trends we have detected here are supported by future studies, non-native species should be a priority for management of marine reserves.     

Marine reserves demonstrate trophic interactions across habitats

Several infaunal bivalve taxa show patterns of decreased biomass in areas with higher densities of adjacent reef-associated predators (the snapper, Pagrus auratus and rock lobster, Jasus edwardsii). A caging experiment was used to test the hypothesis that patterns observed were caused by predation, using plots seeded with a known initial density of the bivalve Dosinia subrosea to estimate survivorship. The caging experiment was replicated at several sites inside and outside two highly protected marine reserves: predators are significantly more abundant inside these reserves. Survivorship in fully caged, partially caged and open plots were then compared at sites having either low (non reserve) or high (reserve) predator density. The highest rates of survivorship of the bivalve were found in caged plots inside reserves and in all treatments outside reserves. However, inside reserves, open and partially caged treatments exhibited low survivorship. It was possible to specifically attribute much of this mortality to predation by large rock lobsters, due to distinctive marks on the valves of dead D. subrosea. This suggests that predation by large rock lobster could indeed account for the distributional patterns previously documented for certain bivalve populations. Our results illustrate that protection afforded by marine reserves is necessary to investigate how depletion through fishing pressure can change the role of upper-level predators and trophic processes between habitats. Electronic Supplementary Material Supplementary material is available for this article at An erratum to this article can be found at     

Management histories of Sumilon and Apo Marine Reserves, Philippines, and their influence on national marine resource policy

 The histories of management of the Sumilon and Apo marine reserves in the Philippines provide a stark contrast. Both began with marine conservation and education programs at the community level, initiated by the Marine Laboratory of Silliman University in 1973 at Sumilon, and in 1976 at Apo. At both islands community support for the “no take” reserve concept evolved gradually, via perceived benefits of increased local fish yields and income from tourism. However, Sumilon reserve has been fished down twice (in 1984,1992), and was still being fished in December 1998. Apo reserve has been protected from fishing successfully for 16 y (1982–1998). The management histories of these two marine reserves are the longest and most detailed available for coral reefs. Scientific data spanning 1976–1993 for Sumilon and 1980–1993 for Apo have provided some of the best available evidence of the utility of such reserves as management tools in coral reef fisheries. At Sumilon, collapse of reserve protection in 1984, after 9.5 y of restrictions on fishing, led to significant declines in reef fisheries yields in areas adjacent to the reserve. At Apo, continuous protection from 1982 to 1993 has led to consistent build up of fish in the reserve and some evidence that local fish yields have increased. The unique time series of scientific data obtained from Sumilon and Apo islands are the result of their distinct management histories. The greater success of management at Apo was due to community support for the reserve concept being actively maintained for the past 16 y. Socio-political factors caused the level of community support for the Sumilon reserve to wax and wane over this period. Both case histories have had a profound effect on marine resource management in the Philippines. As marine reserve models they had substantial influence on the design of the National Integrated Protected Area System (NIPAS). Policy now encourages co-management between the National government and local communities, with a strong emphasis on decentralization of decision making and recognition of local territorial use rights in fisheries. Accepted: 14 May 1999     

Marine reserves demonstrate top-down control of community structure on temperate reefs

Replicated ecological studies in marine reserves and associated unprotected areas are valuable in examining top-down impacts on communities and the ecosystem-level effects of fishing. We carried out experimental studies in two temperate marine reserves to examine these top-down influences on shallow subtidal reef communities in northeastern New Zealand. Both reserves examined are known to support high densities of predators and tethering experiments showed that the chance of predation on the dominant sea urchin, Evechinus chloroticus, within both reserves was approximately 7 times higher relative to outside. Predation was most intense on the smallest size class (30-40 mm) of tethered urchins, the size at which urchins cease to exhibit cryptic behaviour. A high proportion of predation on large urchins could be attributed to the spiny lobster, Jasus edwardsii. Predation on the smaller classes was probably by both lobsters and predatory fish, predominantly the sparid Pagrus auratus. The density of adult Evechinus actively grazing the substratum in the urchin barrens habitat was found to be significantly lower at marine reserve sites (2.2ǂ.3 m^-2) relative to non-reserve sites (5.5ǂ.4 m^-2). There was no difference in the density of cryptic juveniles between reserve and non-reserve sites. Reserve populations were more bimodal, with urchins between 40 and 55 mm occurring at very low numbers. Experimental removal of Evechinus from the urchin barrens habitat over 12 months lead to a change from a crustose coralline algal habitat to a macroalgal dominated habitat. Such macroalgal habitats were found to be more extensive in both reserves, where urchin densities were lower, relative to the adjacent unprotected areas that were dominated by urchin barrens. The patterns observed provide evidence for a top-down role of predators in structuring shallow reef communities in northeastern New Zealand and demonstrate how marine reserves can reverse the indirect effects of fishing and re-establish community-level trophic cascades.     

Changes in Fish Assemblages following the Establishment of a Network of No-Take Marine Reserves and Partially-Protected Areas

Networks of no-take marine reserves and partially-protected areas (with limited fishing) are being increasingly promoted as a means of conserving biodiversity. We examined changes in fish assemblages across a network of marine reserves and two different types of partially-protected areas within a marine park over the first 5 years of its establishment. We used Baited Remote Underwater Video (BRUV) to quantify fish communities on rocky reefs at 20–40 m depth between 2008–2011. Each year, we sampled 12 sites in 6 no-take marine reserves and 12 sites in two types of partially-protected areas with contrasting levels of protection (n = 4 BRUV stations per site). Fish abundances were 38% greater across the network of marine reserves compared to the partially-protected areas, although not all individual reserves performed equally. Compliance actions were positively associated with marine reserve responses, while reserve size had no apparent relationship with reserve performance after 5 years. The richness and abundance of fishes did not consistently differ between the two types of partially-protected areas. There was, therefore, no evidence that the more regulated partially-protected areas had additional conservation benefits for reef fish assemblages. Overall, our results demonstrate conservation benefits to fish assemblages from a newly established network of temperate marine reserves. They also show that ecological monitoring can contribute to adaptive management of newly established marine reserve networks, but the extent of this contribution is limited by the rate of change in marine communities in response to protection.     

Designing connected marine reserves in the face of global warming

Marine reserves are widely used to protect species important for conservation and fisheries and to help maintain ecological processes that sustain their populations, including recruitment and dispersal. Achieving these goals requires well‐connected networks of marine reserves that maximize larval connectivity, thus allowing exchanges between populations and recolonization after local disturbances. However, global warming can disrupt connectivity by shortening potential dispersal pathways through changes in larval physiology. These changes can compromise the performance of marine reserve networks, thus requiring adjusting their design to account for ocean warming. To date, empirical approaches to marine prioritization have not considered larval connectivity as affected by global warming. Here, we develop a framework for designing marine reserve networks that integrates graph theory and changes in larval connectivity due to potential reductions in planktonic larval duration (PLD) associated with ocean warming, given current socioeconomic constraints. Using the Gulf of California as case study, we assess the benefits and costs of adjusting networks to account for connectivity, with and without ocean warming. We compare reserve networks designed to achieve representation of species and ecosystems with networks designed to also maximize connectivity under current and future ocean‐warming scenarios. Our results indicate that current larval connectivity could be reduced significantly under ocean warming because of shortened PLDs. Given the potential changes in connectivity, we show that our graph‐theoretical approach based on centrality (eigenvector and distance‐weighted fragmentation) of habitat patches can help design better‐connected marine reserve networks for the future with equivalent costs. We found that maintaining dispersal connectivity incidentally through representation‐only reserve design is unlikely, particularly in regions with strong asymmetric patterns of dispersal connectivity. Our results support previous studies suggesting that, given potential reductions in PLD due to ocean warming, future marine reserve networks would require more and/or larger reserves in closer proximity to maintain larval connectivity.     

Reef sharks exhibit site-fidelity and higher relative abundance in marine reserves on the Mesoamerican Barrier Reef

Carcharhinid sharks can make up a large fraction of the top predators inhabiting tropical marine ecosystems and have declined in many regions due to intense fishing pressure. There is some support for the hypothesis that carcharhinid species that complete their life-cycle within coral reef ecosystems, hereafter referred to as “reef sharks”, are more abundant inside no-take marine reserves due to a reduction in fishing pressure (i.e., they benefit from marine reserves). Key predictions of this hypothesis are that (a) individual reef sharks exhibit high site-fidelity to these protected areas and (b) their relative abundance will generally be higher in these areas compared to fished reefs. To test this hypothesis for the first time in Caribbean coral reef ecosystems we combined acoustic monitoring and baited remote underwater video (BRUV) surveys to measure reef shark site-fidelity and relative abundance, respectively. We focused on the Caribbean reef shark (Carcharhinus perezi), the most common reef shark in the Western Atlantic, at Glover''s Reef Marine Reserve (GRMR), Belize. Acoustically tagged sharks (N = 34) were detected throughout the year at this location and exhibited strong site-fidelity. Shark presence or absence on 200 BRUVs deployed at GRMR and three other sites (another reserve site and two fished reefs) showed that the factor “marine reserve” had a significant positive effect on reef shark presence. We rejected environmental factors or site-environment interactions as predominant drivers of this pattern. These results are consistent with the hypothesis that marine reserves can benefit reef shark populations and we suggest new hypotheses to determine the underlying mechanism(s) involved: reduced fishing mortality or enhanced prey availability.     

Predation of the sea urchin Heliocidaris erythrogramma by rock lobsters (Jasus edwardsii) in no-take marine reserves

The formation of sea urchin ‘barrens’ on shallow temperate rocky reefs is well documented. However there has been much conjecture about the underlying mechanisms leading to sea urchin barrens, and relatively little experimentation to test these ideas critically. We conducted a series of manipulative experiments to determine whether predation mortality is an important mechanism structuring populations of the sea urchin Heliocidaris erythrogramma in Tasmania. Tethered juvenile and adult sea urchins experienced much higher rates of mortality inside no-take marine reserves where sea urchin predators were abundant compared to adjacent fished areas where predators were fewer. Mortality of tagged (but not tethered) sea urchins was also notably higher in marine reserves than in adjacent areas open to fishing. When a range of sizes of sea urchins was exposed to three sizes of rock lobsters in a caging experiment, juvenile sea urchins were eaten more frequently than larger sea urchins by all sizes of rock lobster, but only the largest rock lobsters (> 120 mm CL) were able to consume large adult sea urchins. Tagging (but not tethering) juvenile and adult sea urchins in two separate marine reserves indicated that adult sea urchins experience higher predation mortality than juveniles, probably because juveniles can shelter in cryptic microhabitat more effectively. In a field experiment in which exposure of sea urchins to rock lobster (Jasus edwardsii) and demersal reef fish predators was manipulated, rock lobsters were shown to be more important than fish as predators of adult sea urchins in a marine reserve. We conclude that predators, and particularly rock lobsters, exert significant predation mortality on H. erythrogramma in Tasmanian marine reserves, and that adult sea urchins are more vulnerable than smaller cryptic individuals. Fishing of rock lobsters is likely to reduce an important component of mortality in H. erythrogramma populations.     

Marine reserves with ecological uncertainty

To help manage the fluctuations inherent in fish populations scientists have argued for both an ecosystem approach to management and the greater use of marine reserves. Support for reserves includes empirical evidence that they can raise the spawning biomass and mean size of exploited populations, increase the abundance of species and, relative to reference sites, raise population density, biomass, fish size and diversity. By contrast, fishers often oppose the establishment and expansion of marine reserves and claim that reserves provide few, if any, economic payoffs. Using a stochastic optimal control model with two forms of ecological uncertainty we demonstrate that reserves create a resilience effect that allows for the population to recover faster, and can also raise the harvest immediately following a negative shock. The tradeoff of a larger reserve is a reduced harvest in the absence of a negative shock such that a reserve will never encompass the entire population if the goal is to maximize the economic returns from harvesting, and fishing is profitable. Under a wide range of parameter values with ecological uncertainty, and in the ‘worst case’ scenario for a reserve, we show that a marine reserve can increase the economic payoff to fishers even when the harvested population is not initially overexploited, harvesting is economically optimal and the population is persistent. Moreover, we show that the benefits of a reserve cannot be achieved by existing effort or output controls. Our results demonstrate that, in many cases, there is no tradeoff between the economic payoff of fishers and ecological benefits when a reserve is established at equal to, or less than, its optimum size.