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1.
Marine protected areas (MPAs) are often promoted as tools for biodiversity conservation as well as for fisheries management. Despite increasing evidence of their usefulness, questions remain regarding the optimal design of MPAs, in particular concerning their function as fisheries management tools, for which empirical studies are still lacking. Using 28 data sets from seven MPAs in Southern Europe, we developed a meta‐analytical approach to investigate the effects of protection on adjacent fisheries and asking how these effects are influenced by MPA size and age. Southern European MPAs showed clear effects on the surrounding fisheries, on the ‘catch per unit effort’ (CPUE) of target species, but especially on the CPUE of the marketable catch. These effects depended on the time of protection and on the size of the no‐take area. CPUE of both target species and the marketable catch increased gradually by 2–4% per year over a long time period (at least 30 years). The influence of the size of the no‐take area appeared to be more complex. The catch rates of the entire fishery in and around the MPA were higher when the no‐take areas were smaller. Conversely, catch rates of selected fisheries that were expected to benefit most from protection increased when the no‐take area was larger. Our results emphasize the importance of MPA size on its export functions and suggest that an adequate, often extended, time frame be used for the management and the evaluation of effectiveness of MPAs.  相似文献   

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  • 1. Coral reefs around the world have been deteriorating over decades owing to anthropogenic pressure. In the Caribbean recent rates of decline are alarming, particularly for coral reefs under high local human impact, many of which are severely degraded, although regions with lower direct anthropogenic influence seem less affected.
  • 2. Little Cayman is a relatively undeveloped island, with less than 150 permanent residents. About 20% of its reefs have been protected by no‐take marine reserves since the mid‐1980s. We analysed the dynamics of coral communities around the island from 1999 to 2004 in order to test the hypothesis that a lack of major local anthropogenic disturbances is enough to prevent decline of coral populations.
  • 3. Live hard coral coverage, coral diversity, abundance, mortality, size, and prevalence of disease and bleaching were measured using the Atlantic and Gulf Rapid Reef Assessment methodology (line transects) at nine sites. Despite the apparent undisturbed condition of the island, a 40% relative reduction of mean live coral coverage (from 26% to 16%, absolute change was 10%) was recorded in five years. Mean mortality varied from year to year from 23% to 27%. Overall mean diameter and height have decreased between 6% and 15% on average (from 47 to 40 cm for diameter, and from 31 to 29 cm for height).
  • 4. The relative abundance of large reef builders of the genus Montastraea decreased, while that of smaller corals of the genera Agaricia and Porites increased. Disease prevalence has increased over time, and at least one relatively large bleaching event (affecting 10% of the corals) took place in 2003.
  • 5. Mean live coral cover decline was similar inside (from 29% to 19%) and outside (from 24% to 14%) marine no‐take reserves. No significant difference in disease prevalence or clear pattern in bleaching frequency was observed between protected and non‐protected areas. It is concluded that more comprehensive management strategies are needed in order to effectively protect coral communities from degradation.
Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

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ABSTRACT:   A feedback management procedure is proposed that is based on controlling the size of a Marine Protected Area (MPA): increasing the size of the MPA when the population is below a predetermined target level and reducing its size when it is above. The objective of fisheries management is to have the population size approximate the target level. Local stability was analyzed, to determine whether a population could remain close to the target level with small perturbations, using a generalized population dynamics model without including an age structure. The procedure was able to sustain the population at the target level if the target was set at a level that gives the maximum sustainable yield and if drastic changes in the MPA size were avoided. Global stability was analyzed numerically to determine whether a population would always approach the target level regardless of the present population size, using a specified model that allowed for temporal changes in the spatial distribution of a sedentary population. The procedure, which did not require direct control of catch quota or fishing effort, appeared to attain the objective successfully.  相似文献   

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  1. Coral reef biodiversity is rapidly decreasing as a result of the loss of coral cover, which modifies the structure and functioning of the ecosystem. Understanding how coral reef communities respond in space and over the long term is essential in order to implement management strategies and reduce the effects of biodiversity loss on coral reefs.
  2. Fish, coral, and algae communities were used as indicators to evaluate changes in coral reef systems. The variation of these communities was studied in a marine protected area composed of three management zones in Cozumel Coral Reef National Park in Quintana Roo, Mexico, over a period of 11 years (2004–2014). The following parameters were monitored annually: (i) total fish density; (ii) fish trophic group densities; (iii) species richness and three fish diversity indices; (iv) relative scleractinian coral cover; and (v) relative macroalgae cover.
  3. In the years in which coastal development, such as the construction of a marina, took place, an increase in the abundance of territorial herbivorous and planktivorous fish was observed. As the coral recovered, macrocarnivores and sessile benthic invertivores were re‐established, whereas scraper herbivores showed no changes in the period of study in any of the three management zones.
  4. Coral cover recovery showed rapid phase‐shift reversal (phase‐shift, macroalgae dominance over coral) in the three zones. Even though the fish density and coral cover recovered, the diversity indices of each fish trophic group exhibited a reduction in the three management zones over time.
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Fishers’ perceptions of changes in grouper size and abundance were compared with scientific data collected via underwater visual censuses (UVCs) before (1995) and after (2006 and 2011) the establishment of the Mafia Island Marine Park. Perceptions on changes in the size structure of groupers differed among communities due to differences in fishing capacities. Fishers in one village had mixed perceptions, while in another village the majority (66%) perceived a decline in size, with small groupers dominating the catch. Similarly, UVCs indicated that size structure was dominated by small groupers at all times surveyed. Consistent with fishers’ perceptions, UVC indicated that biomass and abundance of groupers declined in both no‐take zones (NTZs) and specified‐use zones (SUZs) between 1995 and 2006, with no substantial changes between 2006 and 2011. The NTZs had higher density and diversity of grouper species than SUZs, as would be expected from the differences in bottom topography in these two types of areas. The idea that NTZs could increase the biomass and abundance of groupers to benefit fished zones was not found, thus indicating that NTZs are not necessarily the best option for managing reef fisheries.  相似文献   

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  • 1. An expansion of no‐take marine reserve zones of Australia's 348 000 km2 Great Barrier Reef (GBR) Marine Park from 4.6% to 33.4% of the park area is proposed in 2004. However, limited evidence currently exists that no‐take marine reserves on the GBR have increased abundance of reef fish targeted by fisheries. This study provides such evidence for inshore reefs of the GBR.
  • 2. Underwater visual surveys were used to estimate the effect of no‐take reserves on abundance of species targeted by hook‐and‐line fisheries around the Palm, Whitsunday and Keppel Islands, spanning 600 km of the length of the GBR. The reserves had been zoned ‘no fishing’ for 14 yr.
  • 3. Densities of Plectropomus spp. and Lutjanus carponotatus, both targeted by fisheries, were much higher in protected zones than fished zones in two of the three island groups. Plectropomus spp. were 3.6 and 2.3 times more abundant in protected than fished zones of the Palm and Whitsunday island groups. L. carponotatus were 2.3 and 2.2 times more abundant in protected zones than fished zones of the Whitsunday and Keppel island groups.
  • 4. The biomasses of Plectropomus spp. and L. carponotatus were significantly greater (3.9 and 2.6 times respectively) in the protected zones than fished zones at all three island groups.
  • 5. Legal minimum sizes of Plectropomus spp. and L. carponotatus are ?38 cm and 25 cm TL respectively. There were significantly higher densities and biomasses of Plectropomus spp. >35 cm TL (density: 3.8 times; biomass: 5.1 times) and L. carponotatus >25 cm TL (density: 4.2 times; biomass: 5.3 times) in protected zones than fished zones at all three island groups.
  • 6. No significant difference in abundance between protected and fished zones was found for two species not captured by fisheries (Siganus doliatus and Chaetodon aureofasciatus), and there were no significant differences in benthic characteristics between protected and fished zones.
  • 7. Results suggest that no‐take marine reserves have increased stock biomass of targeted fish species on inshore GBR reefs.
Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

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  • 1. Marine protected areas (MPAs) are today's cornerstone of many marine conservation strategies. Our 2015 study (Devillers et al., 2015) and others have shown, however, that the placement of MPAs is ‘residual’ to commercial uses and biased towards areas of lower economic value or interest.
  • 2. In this paper, we explored the impact of our study on marine science, policy and management practice.
  • 3. We reviewed the papers citing our work and compiled expert opinions on some of the impacts of our study.
  • 4. Results indicate a strong general uptake in the scientific community but more uneven impacts on policy and management in different contexts, with a likely smaller impact of the research on conservation practice.
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  • 1. Although marine protected areas (MPAs) are often established to protect threatened top‐order predators, there is a paucity of data that can be used to evaluate their efficacy in achieving this purpose.
  • 2. We assessed the effectiveness of a network of MPAs around Macquarie Island in the Southern Ocean by examining the foraging areas of breeding black‐browed Thalassarche melanophrys and grey‐headed albatrosses T. chrysostoma.
  • 3. During late incubation and brood periods over 90% of time spent foraging by black‐browed albatrosses was contained within MPAs, principally the Economic Exclusion Zone (EEZ) around Macquarie Island. In contrast, grey‐headed albatrosses spent only 34% of their time foraging in MPAs.
  • 4. Black‐browed and grey‐headed albatrosses spent 30% and 15% of their respective foraging times in the Marine Park around Macquarie Island.
  • 5. Both black‐browed and grey‐headed albatrosses foraged in Antarctic waters under the jurisdiction of the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR), accounting for 5% and 12% of the total foraging times respectively.
  • 6. The spatial extent of MPAs around Macquarie Island appear to adequately cover much of the foraging distribution of breeding black‐browed albatrosses from Macquarie Island.
  • 7. Breeding grey‐headed albatrosses spend significantly more time in waters outside the spatial extent of the surrounding MPAs and are at higher risk from fisheries activities and other threats.
  • 8. Further information on the foraging movements both of albatrosses outside the breeding season and of juvenile albatrosses is required to more fully assess the efficacy of MPAs in protecting foraging habitats of these species.
Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

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We assessed by numerical modeling the coastal fish larval dispersion along the southern coast of Mallorca (Balearic Islands, NW Mediterranean) with the objective of determining the factors that contribute to successful recruitment. We assumed that fish larvae dispersal is mainly regulated by physical transport. Currents are mainly wind driven in this area; therefore, changes in wind forcing have a first‐order impact on larval transport. The synoptic wind patterns were systematically analyzed based on self‐organizing map analysis. The wind fields were clustered using a neural network pattern recognition approach into two modes, producing opposite along‐shelf flow. The seasonal changes between spring and summer in the dominance of either mode modulate the along‐shelf circulation, producing flow shifts under some circumstances. This variability in the wind regime was consistent throughout the 10 years analyzed (2000–2009). Using the Princeton Ocean Model (POM) and a particle‐tracking algorithm, we analyzed the effect of wind‐forced currents in the connectivity among near‐shore habitats. We show that, at the spatial scale considered, the coastal morphology and stochastic wind forcing favor local recruitment (mean of 30% self‐recruitment). Maximum transport distances of 20–30 km were typically associated with particles left to drift for 21 days. The implications for the performance of the four marine protected areas near SW Mallorca Island are discussed. Our results suggest that, although wind episodes determine the fate of short‐time spawning events, on a seasonal basis, regular larval supply to coastal zones is ensured by wind stochasticity.  相似文献   

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  1. Despite a relatively long history of scientific interest fuelled by exploratory research cruises, the UK deep sea has only recently emerged as the subject of targeted and proactive conservation. Enabling legislation over the past 10 years has resulted in the designation of marine protected areas and the implementation of fisheries management areas as spatial conservation tools. This paper reflects on progress and lessons learned, recommending actions for the future.
  2. Increased investment has been made to improve the evidence base for deep‐sea conservation, including collaborative research surveys and use of emerging technologies. New open data portals and developments in marine habitat classification systems have been two notable steps to furthering understanding of deep‐sea biodiversity and ecosystem functioning in support of conservation action.
  3. There are still extensive gaps in fundamental knowledge of deep‐sea ecosystems and of cause and effect. Costs of new technologies and a limited ability to share data in a timely and efficient manner across sectors are barriers to furthering understanding. In addition, whilst the concepts of natural capital and ecosystem services are considered a useful tool to support the achievement of conservation goals, practical application is challenging.
  4. Continued collaborative research efforts and engagement with industry to share knowledge and resources could offer cost‐effective solutions to some of these barriers. Further elaboration of the concepts of natural capital and ecosystem services will aid understanding of the costs and benefits associated with human–environment interactions and support informed decision‐making in conserving the deep sea.
  5. Whilst multiple challenges arise for deep‐sea conservation, it is critical to continue ongoing conservation efforts, including exploration and collaboration, and to adopt new conservation strategies that are implemented in a systematic and holistic way and to ensure that these are adaptive to growing economic interest in this marine area.
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