Isolation can provide marine ecosystems with a refuge from human impacts. However, information on the biodiversity, ecology and fisheries of remote regions is often sparse. The proposed Coral Sea Marine Reserve could create one of the world's largest and most remote marine parks, yet little information is available to inform discussions. Fish captures from the Coral Sea and adjacent Great Barrier Reef (GBR) were assessed from reports contained in a chronology of spearfishing publications from 1953 to 2009, and reveal for the first time the history of recreational spearfishing in the Coral Sea. Although the area is perceived as relatively untouched, the data indicate that spearfishers have frequented Coral Sea reefs for at least 43 years and reported captures have increased exponentially. Post-1993 trophy captures in the Coral Sea (mean 23 kg) were larger than the adjacent GBR (9 kg). Reef species characterize the GBR catch, while large pelagic species characterize the Coral Sea catch. Provided that functionally important fishes are not targeted, the relatively small scale of recreational spearfishing and the focus on pelagic species suggests that spearfishing currently exerts limited pressure on the ecology of Coral Sea reefs.

We report 37 species of heterobranch sea slugs from the National Park Alacranes reef, located in the Campeche Bank, at the south-eastern Gulf of Mexico, of which 18 species are reported for the first time in this reef. With this contribution, the species richness in this national park increases to up to 67. The species Nakamigawaia felis, Petalifera sp., Elysia flava, Elysia pratensis and Bulbaeolidia sp. are reported in the Gulf of Mexico for the first time. The geographical distribution ranges for Oxynoe azuropunctata, Elysia ornata, Placida kingstoni, Aphelodoris antillensis and Tritonia hamnerorum are extended westward. Those for Elysia flava, Pleurobranchus areolatus and Felimare ruthae are extended both northward and westward.

Marine protected areas (MPAs) are increasingly being considered and used for the management of fisheries targeting mobile fish populations. Here, the recent modelling literature on MPA effects for mobile fish populations and their fisheries is reviewed. Modelling studies conducted since 2011 have filled a considerable number of knowledge gaps on the impacts of MPAs for species exhibiting home-range behaviour, nomadic movements or behavioural polymorphism, and on the effects of “targeted MPAs”, which aim to protect relatively small areas where migratory fishes spend an inordinate fraction of time or are highly vulnerable to fishing (e.g., nursery or spawning zones). Also, in recent years, two studies investigated the consequences of MPAs targeting highly migratory (tuna-like) fish populations for the first time in the history of MPA modelling. Recent modelling studies found that MPAs aimed at protecting mobile species may have positive conservation effects under a relatively wide range of situations, but may generate long-term fisheries benefits only under a very limited set of conditions. In particular, MPAs were not found to be beneficial for the fisheries targeting highly migratory populations. Strategies producing both conservation and fisheries benefits were identified, which depend on fish movement patterns and numerous aspects of fish life history and fisheries dynamics. However, in view of the diversity of fish movement patterns in MPA systems and current dynamics in resource management, it is clear that additional modelling work is needed to fully understand how protected areas affect mobile fish populations and their fisheries and to be able to implement pertinent MPAs. In particular, future modelling studies should systematically assess the effects of MPAs in relation to other management tools to find strategies that are most effective in meeting management objectives, and explore the impacts of “dynamic” MPAs that follow highly migratory fish populations in space and time.

The benefits of implementing no-take Marine Protected Areas (MPAs) for the conservationof highly migratory species are not easy to assess. They depend on several factors, suchas the fish mobility, fisher behaviour and the area covered by the MPA with respect to thedistribution area of the species to protect. In this study, we explore the simultaneouseffects of MPAs and fishing scenarios on skipjack tuna population dynamics, using thespatially-explicit APECOSM-E model. The model represents the size-structured populationdynamics of skipjack tuna in the Indian Ocean and their dependence on climatic variabilityand exploitation by fisheries. Numerical experiments were run from the beginning ofindustrial fisheries in the early 1980s to the year 2030, considering different scenariosfor the future development of fisheries. These scenarios combined different trends infishing effort and technological development, either assuming a continuous increasefollowing historical trends or a stabilization of these factors at present values. Thesimulations were designed to explore the effects of two MPAs of different size andlocation: the recently established Chagos MPA, and a hypothetical MPA covering a largepart of the Western Indian Ocean, where most of the skipjack catches are presently made.We modelled the redistribution of fishing effort around the MPAs assuming that the fishershad partial knowledge of the spatial distribution of the skipjack population. The effectsof the two MPAs on the population dynamics, catch and fishing mortality are shown. Ourresults revealed a very minor effect of the Chagos MPA on the skipjack tuna population,while the Western Indian Ocean MPA had an important impact on the fishing mortality andsucceeded in stabilizing the spawning population. The simulations also showed that theeffect of an MPA depends on the evolution of fisheries and it is therefore important toexplore different fishery scenarios to assess the future benefits of an MPA.

In order to better understand community-level effects of fishing on temperate reefs at continental scales, changes in densities of common species in five Australian marine protected areas (MPAs) were estimated from prior to establishment to three years after enforcement of fishing prohibitions. A before-after-control-impact survey design was used, with 5–14 replicated sites distributed within both sanctuary and fishing zones associated with each MPA. On the basis of published meta-analyses, exploited species were generally expected to show increased densities. By contrast, only two of the 11 exploited fish species (the red morwong Cheilodactylus fuscus and latrid trumpeter Latridopsis forsteri), and none of seven exploited invertebrate species, showed significant signs of population recovery within sanctuary zones. Four fish species increased in biomass between survey periods. When variation in abundance data was partitioned by PERMANOVA independently for the five MPAs, the ‘zone × year’ interaction component consistently contributed only c. 4% of total variation, compared to site (c. 35%), zone (c. 8%), year (c. 8%) and residual error (c. 45%) components. Given that longer-term Australian studies show clear community-wide responses following MPA protection, the discrepancy between weak observed recovery and a priori expectations is probably due, at least in part, to the three-year period studied being insufficient to generate clear trends, to relatively low fishing pressure on some temperate Australian reefs, and to meta-analyses overestimating the likelihood of significant short-term population responses.

Monitoring species’ response in marine protected areas is important for informing both the management of those areas and the establishment of additional protected areas. Populations of spiny lobsters Jasus edwardsii were monitored in eight New Zealand marine reserves for up to 34 years. The populations displayed highly variable responses to protection. While a few showed rapid (within 1–2 years of protection) increases in abundance, others showed little response even after a decade of protection. Some reserves displayed little initial recovery, then a sudden increase following several years of protection, while others displayed significant declines in abundance following initial recovery. Marine reserves located in areas with initially high densities of juveniles tended to have rapid recovery, but aspects of reserve design had no significant influence on the recovery rate. Variability among recovery trajectories also suggests that supply-side dynamics may be a key driver of lobster recovery. Densities of legal-sized lobsters were positively correlated with reserve age, but the abundance of juvenile lobsters increased in all but one reserve, indicating enhanced recruitment, survival and/or movement of juvenile lobsters into reserves. It is important to consider the placement of reserves, with respect to potential levels of larval supply, when establishing marine reserves for either conservation or fisheries management purposes and for evaluating their effectiveness.

The scientific literature (including some of the most high-profile papers) on the ecological and fisheries effects of permanent no-take marine reserves is dominated by examples from hard tropical and warm temperate ecosystems. It appears to have been tacitly assumed that inference from these studies can directly inform expectations of marine reserve effects in cooler temperate and cold temperate waters. Trends in peer-reviewed studies indicate that the empirical basis for this assumption is tenuous because of a relative lack of research effort in cooler seas, and differences between tropical and temperate regions in ecology, seasonality, the nature of fisheries and prevailing governance regimes.

Fisheries in Puerto Rico and the United States (US) Virgin Islands are predominately dependent on nearshore coral reef ecosystems and have suffered from historical overfishing. The unique characteristics of reef fisheries, including strong habitat dependence, susceptibility to coastal impacts, diffuse landing sites and strong multispecies and multigear interactions suggest that standard approaches to fisheries management, especially those typically considered by the US Regional Fishery Management Councils, would not be applicable. Current management authority is split between local and federal agencies; however, there exists no uniform context and direction to current management initiatives, which results in lost efficiencies and opportunities. Proposed here is a new vision for fisheries management that takes into consideration the local ecological and socioeconomic characteristics of fishing, is compatible with regional resources and capacity, is ecosystem based and targets full stakeholder participation. Only an ecosystem-based approach can lead fisheries management out of the trap of unrealistic data collection and analysis demands, while at the same time refocusing emphasis away from attitudes and practices that promote overfishing. Management must be based on first principles regarding the desired state of the ecosystem and initiate strategies based on these principles. The key management goal is not to maximize fisheries catch, but to maintain the ecosystem in a state that will lead to sustained production. First principles would include maintaining ecosystem integrity and function, protecting all habitats and water quality, applying the precautionary approach, monitoring reference points and recognizing that production has limits. Resulting management tactics include marine reserves (to meet multiple goals), closed spawning aggregations, gear restrictions to maintain trophic balance and habitats, targeted data collection and assessments, adopting co-management practices and using ecosystem or community-based metrics. Fisheries management must fully incorporate the tools, resources and methods available within coastal zone management and other environmental agencies, while standards within those programmes must protect ecosystem health. Implementation will require attending to structural barriers inherent within existing fisheries legislation and regulations, multiple jurisdictions and the current cultures of scientists, managers and fisherfolk. Initial efforts should focus on developing a common language and frame of reference for all stakeholders.

The protected sites defined under the Marine Conservation Corridor of the Tropical Eastern Pacific (MCCTEP) include most of the endemism and a fraction of the areas of high diversity for reef corals and fishes. Although those areas are connected biologically over distances >600 km, lack of large-scale sampling and attention to taxa other than scleractinian corals has limited the protection of shallow coral reef and coral community habitats in some areas of the Tropical Eastern Pacific (TEP) region, particularly non-offshore islands in Ecuador, Panama and Costa Rica. The newly created Las Perlas marine protected area (1688 km2), the second largest archipelago in the TEP, fills a regional conservation gap for the protection of reefs and potentially becomes the second highest coral diversity area in the MCCTEP. This study describes the distribution of live coral cover and species alpha-diversity over 307 ha of shallow coral reefs and coral communities in the Las Perlas Archipelago. Nineteen scleractinian and 38 octocorals were observed, including species previously thought to be uncommon. Although coral communities generally had a greater number of species than coral reefs, species richness did not differ between habitats. However, their coral and octocoral composition and benthic makeup (coral cover, macroalgae, sponge, etc.) differed. The reefs had higher live coral cover (61.2%) and lower algal cover (32.5%) than the coral communities (26.0% and 65.7%, respectively). Octocorals were more common in the communities than on the reefs. There was a negative relationship between live coral cover and species richness, low to moderate cover generally coinciding with coral community sites and higher species richness. Areas are recommended for marine reserve zoning within the new Las Perlas marine protected area to ensure the protection of important habitats and maintenance of diversity in the TEP, both highlighting the importance of the southern islands of the archipelago for coral diversity and the northern islands for their high live coral cover. Review of the representativeness of regional coral diversity would facilitate better design of small-scale reserves across the TEP, following comparable survey methods.

Marine sanctuaries are increasingly being promoted as tools for conservation and fisheries management. This study investigates the effects of protection over 19 years on substrate composition and fish communities in four marine sanctuaries and corresponding non-sanctuary areas in the Philippines and examines the importance of community support, management measures and enforcement of regulations on these ecological effects. Between 1981 and 2000, substrate cover variables were measured using line transects with scuba and snorkel surveys, and fish censuses (identification to family level) were conducted using scuba within a 500 m2 area. Semi-structured interviews collected data on community support for the sanctuaries, and observations and interviews established management and enforcement aspects of the sanctuaries. Over time, all sanctuaries showed improvements, or maintenance of, ecological variables compared with pre-enforcement times, with maintenance of hard coral cover and average increases of 8.3% in fish species richness and 54.9% in fish abundance. In comparison, non-sanctuary areas showed maintenance of the status quo or declines in ecological variables. However hard coral cover, fish abundances and fish species richness showed significant declines as well as increases in sanctuary areas. Community, management and enforcement factors were significantly related to positive ecological trends in sanctuary areas; management and enforcement were related to a wider variety of ecological factors than community score. Community support was significantly related to an increase in hard coral cover in deep areas. Enforcement of regulations was significantly related to an increase in abundance of fishery target fish species in sanctuary areas, and simple management measures were significantly related to an increase in abundance of large predators. Supportive communities that voluntarily implemented sanctuary regulations, improved enforcement, and small discrete cohesive communities may have facilitated the process of building this community support. Well-enforced sanctuaries that showed an increase in abundance of target species may have contributed to the maintenance of fish yields in adjacent non-sanctuary areas. The effects of sanctuary implementation varied on a case-by-case basis, influenced by environmental, biological, physical and human factors. However, a combination of community support, management measures and enforcement of regulations contributed towards positive ecological trends in sanctuary areas.

In the last 15 years new research findings have radically reshaped our understanding of human effects on ocean ecosystems. Here I describe five major shifts in perspective that reveal our impacts to be more severe and persistent than previously appreciated. Firstly, scientists have delved deep into the past and found that the global expansion of European nations across the planet caused the large-scale loss of marine megafauna. In the past century, expansion of industrial scale fishing has continued the process, massively reducing the biomass of exploited species. Secondly, once depleted we are finding that populations rarely rebound rapidly, contrary to a widespread belief in greater resilience of marine compared to terrestrial species. Thirdly, marine ecosystems are being shifted into alternative states that are less desirable from the human perspective and may be stable. It could be difficult, or impossible in some cases, to reverse impacts once inflicted. Fourthly, marine species are at risk of extinction. Loss of shallow water marine habitats is proceeding as rapidly as on land, many species have small geographic ranges, and many possess life history characteristics that leave them highly susceptible to overexploitation. Finally, the deep sea is not beyond harm. Depletion of shallow water fisheries and technological advances are opening up the deep to exploitation and its collateral impacts. If we are to reverse these negative trends we must establish large-scale networks of marine reserves that are off limits to damaging activities and fishing. Such reserves would protect biodiversity, and recover and sustain the world's fisheries productivity.

Marine protected areas (MPAs) may be important for protecting the marine environment, but they may also have substantial socio-cultural impacts about which very little is currently known, or acknowledged. In the Mediterranean, few data are available on the socio-economic consequences of MPAs. The present study reviews the existing data on MPAs in Spain, France, Italy and Greece. A general increase in tourist activities in Mediterranean MPAs is evident, as are increases in the abundances of larger fish species, although there are no data indicating yields for fisheries increase adjacent to MPAs. A large increase in the number of divers and vessels using MPAs has already had impacts on natural benthic communities as a result of diver damage, mooring and the feeding of large fish by divers. Emphasis has been given in only a few MPAs to promoting public awareness of these impacts. Although the conservation of nature should be considered the fundamental objective of MPAs, neglecting their social, cultural and economic impacts has at times led to poor local consensus, if not hostility. We believe that planning and managing MPAs should be conducted on a multidisciplinary basis. Nonetheless, no single model can be considered valid for the whole Mediterranean. The very variable characteristics of coastal areas, from those of small uninhabited islands to those of cities, require different weightings to be assigned for each factor in order to achieve a durable equilibrium and realize the original objectives of each MPA. Only with such flexibility of management will it be possible to reach a greater understanding of the MPA system and create a lasting consensus in favour of conservation, a consensus which would mean an overwhelming majority of people actively avoiding damaging nature and preventing others from doing so.

The cessation or reduction of fishing in marine protected areas (MPAs) should promote an increase in abundance and mean size and age of previously exploited populations. Thus density-dependent changes in life-history characteristics should occur when populations are allowed to recover in MPAs. In this review, we synthesize the existing information on resource limitation in marine ecosystems, density-dependent changes in life-history traits of exploited populations and evidence for biomass export from MPAs. Most evidence for compensatory changes in biological variables has been derived from observations on populations depleted by high fishing mortality or on strong year classes, but these changes are more evident in juveniles than in adults and in freshwater rather than in marine systems. It is unclear if adults of exploited marine populations are resource limited. This may suggest that exploited populations are controlled mainly by density-independent processes, which could be a consequence of the depleted state of most exploited populations. MPAs could be a useful tool for testing these hypotheses. If we assume that resources become limiting inside MPAs, it is plausible that, if suitable habitats exist, mobile species will search for resources outside of the MPAs, leading to export of biomass to areas which are fished. However, it is not possible to establish from the available data whether this export will be a response to resource limitation inside the MPAs, the result of random movements across MPA boundaries or both. We discuss the implications of this process for the use of MPAs as fisheries management tools.

The large number of marine protected areas (MPAs) in the Caribbean (over 100) gives a misleading impression of the amount of protection the reefs and other marine resources in this region are receiving. This review synthesizes information on marine resources in two of the first MPAs established in the USA, namely Virgin Islands National Park (1962) and Buck Island Reef National Monument (1961), and provides compelling evidence that greater protection is needed, based on data from some of the longest running research projects on coral reefs, reef fish assemblages, and seagrass beds for the Caribbean. Most of the stresses affecting marine resources throughout the Caribbean (e.g. damage from boats, hurricanes and coral diseases) are also causing deterioration in these MPAs. Living coral cover has decreased and macroalgal cover has increased. Seagrass densities have decreased because of storms and anchor damage. Intensive fishing in the US Virgin Islands has caused loss of spawning aggregations and decreases in mean fish size and abundance. Groupers and snappers are far less abundant and herbivorous fishes comprise a greater proportion of samples than in the 1960s. Effects of intensive fishing are evident even within MPA boundaries. Although only traditional fishing with traps of ‘conventional design’ is allowed, commercial trap fishing is occurring. Visual samples of fishes inside and outside Virgin Islands National Park showed no significant differences in number of species, biomass, or mean size of fishes. Similarly, the number of fishes per trap was statistically similar inside and outside park waters. These MPAs have not been effective because an unprecedented combination of natural and human factors is assaulting the resources, some of the greatest damage is from stresses outside the control of park managers (e.g. hurricanes), and enforcement of the few regulations has been limited. Fully functioning MPAs which prohibit fishing and other extractive uses (e.g. no-take marine reserves) could reverse some of the degradation, allowing replenishment of the fishery resources and recovery of benthic habitats.