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1.
Reef fish are critical in maintaining the ecological function of coral reefs and providing food security for coastal communities in developing countries. Reef fishery stocks are under increasing threat from factors such as climate-related habitat degradation, land use practices, and resource extraction related to human population growth, direct consumption and increasing connectivity between the in situ fishery and fish markets. This study investigates how reef fish stocks are related to environmental, localised resource use and market proximity indicators across 51 sites in the Solomon Islands. Hard coral cover is the best indicator of total target fishery biomass, with cover of less than around 31% associated with significantly less biomass than sites with higher coral cover. Direct resource use indicators such as fish consumption and fish sale pressure were poor predictors of target fish biomass. Distance of the fishery resource from community, provincial sub-station, provincial capital and national capital are all significantly and positively correlated with biomass for four key fishery families: Acanthuridae (surgeonfish), Scaridae (parrotfish), Lethrinidae (emperor), Lutjanidae (snapper). Multiple spatial scale relationships are evident between market proximity indicators and Lutjanidae and Scaridae families. Thus, while pooled target fishery biomass is constrained by environment, analysis at fishery family resolution reveals the effects of anthropogenic impact through market proximity on constraining fishery biomass distribution in the Solomon Islands. This study highlights the need for reef fishery managers and conservation practitioners to focus attention on proximity of resources to markets to sustain the ecological health of reef dominated ecosystems.  相似文献   

2.
The present study is the first to determine priorities for the location of marine reserves using spatial prioritization software in the eastern Mediterranean Sea. We used biophysical data from visual census surveys on: fish species abundance, presence of various habitat types, and percent coverage of seagrasses and canopy algae. Efficient conservation planning requires spatially explicit information on how proposed management will affect stakeholders, which in this region was very limited. We created novel socio-economic cost indices to account for fisheries and tourists. Our fishing metrics were based on fisher behaviour including information on the location of ports and areas often inaccessible to fishers due to high wind exposure. We developed a cost index for tourism based on the availability of beds for tourists. We examined how the spatial priorities for marine reserves varied using different combinations of these socio-economic cost metrics. We found about 17% of sites were a high priority regardless of which cost metric was used. We also compared, for the first time in the Mediterranean, our results devised using systematic conservation planning approaches with priorities developed by two non-systematic methods, the Natura 2000 proposed marine reserves and sites that local fishers proposed for protection. Only a few sites identified by our approach were the same as those recommended as part of Natura 2000 or the fishers’ proposals. This suggests that much more work is needed to harmonise existing proposals with the principles of efficient systematic conservation planning.  相似文献   

3.
Marine protected area (MPA) networks designed without consideration of the interests of local communities are likely to fail. However, in many regions where conservation action is needed most urgently, socioeconomic data are not available at spatial scales relevant to conservation planning. In the Philippines, the primary stakeholders relevant to conservation efforts in coastal waters are small-scale fishers. Unlike commercial fisheries, no logbook data are kept to record fishers’ spatial effort and usage patterns. We investigated the effects of including different surrogates for small-scale fishing effort in the systematic design of an MPA network for Siquijor Province. We compared a reserve selection scenario in which socioeconomic data were not considered with four different surrogates for fishing effort and with empirical data on the spatial distribution of fishing effort collected through interviews. We assumed that minimising opportunity costs to fishers would increase the likelihood that they would support and comply with MPA implementation, resulting in more effective conservation. Surrogates modelled on the number of fishers or boats in each community consistently outperformed those based on population census data. However, none of the surrogates we tested were able to accurately predict fine-scale resource use patterns. Whilst socioeconomic surrogates may be able to assist conservation planners to identify regional-scale opportunities where conservation objectives may be met more easily, they cannot act as a shortcut for comprehensive consultation with communities, which will be required to identify actual sites for MPA implementation.  相似文献   

4.
We analyzed fisher interview data collected in the Raja Ampat archipelago of Eastern Indonesia to demonstrate a perceived decline in the abundance of living marine resources targeted by commercial and artisanal fisheries. The decline appeared ubiquitous among all tested species and a clear trend emerged in which older fishers recall greater past abundance than younger fishers. This provides evidence for the shifting baseline syndrome, a dangerous cognitive condition in which each generation of fishery stakeholders accepts a lower standard of resource abundance as normal. We used a fuzzy expert system to standardize and quantify the anecdotal evidence, and combine it with additional depletion indicators to produce a decadal time series of resource abundance from 1970 to present. Using governmental catch-per-unit-effort data from more recent years we hindcasted to establish an absolute scale with which to interpret the perceived decline. The interview information suggested that some exploited species may have declined by as much as an order of magnitude since 1970.  相似文献   

5.
Marine protected areas can enhance fish stocks within their boundaries, but the circumstances in which they might also supplement stocks or enhance fisheries outside their boundaries are less clear. Using visual survey and fishery data, we assess the impacts of increasing fishing effort, and of the establishment in Hawaii of a network of areas closed to aquarium fishing, on the prime-target species, yellow tang (Zebrasoma flavescens), and draw conclusions about MPA impacts on long-term fishery sustainability. Between 1999, when 27.8% of the coastline was closed to collecting, and 2007, the number of active fishers and total catch of yellow tang doubled. Prior to MPA establishment, yellow tang densities were similar at sites open to fishing and those slated for closure. By 2007, closed areas had five times the density of prime targeted sized fish (5-10 cm), and 48% higher density of adults than open areas. Densities of adults in ‘boundary’ areas (open areas <1 km from nearest MPA boundary) were significantly higher than in open areas far from MPA boundaries, which was indicative of spillover at that scale. Given the long life-span of yellow tang (>40 years) relative to the duration of protection and the increasing intensity of fishing, the likelihood is that protected areas will become increasingly important sources for the adult fishes which will sustain stocks and the fishery over the longer term.  相似文献   

6.
Marine protected areas (MPAs) are increasingly envisaged as a tool to manage coastal ecosystems and fisheries. Assessment of their performance with respect to management objectives is therefore important. A number of MPAs provided conservation benefits for fished species. Observed benefits do not apply to all species at all times, and responses to protection are also highly variable among fish taxa. Among the many empirical studies on marine reserves, only a few designs considered ‘before and after data’ and spatial variation. In this paper, we are interested in assessing the effect of a no-take reserve on the reef fish assemblage in a northwestern Mediterranean example. Data were obtained from a three-year survey using underwater visual censuses (UVC), before and after MPA establishment. Permutational multivariate analysis of variance (PERMANOVA) and multivariate regression trees (MRT) were used to evaluate the effects of reserve protection on the reef fish assemblage, while accounting for habitat. Modelled biological responses were abundances and diversity indices calculated at different levels of the assemblage. Significant effects were found for many of these metrics. In addition to PERMANOVA, univariate models provided more insight into the magnitude and direction of effects. The most sensitive metrics were related to large species and species targeted by fishing. These results may be used to choose the metrics that are more suitable as community-based indicators of MPA impact in the perspective of monitoring programs.  相似文献   

7.
The vast Brazilian coast harbors unique and diverse reef fish communities. Unfortunately, relatively little is known about the impact of fishing on these fish species, and few management or conservation efforts are being made to protect them. Here, we examine the effect of different levels of protection on the composition, abundance, and size structure of reef fish species along a 2500 km portion of the Brazilian coastline, noting in particular the relative abundance of endemics and the effect of protection on these species. Pairwise comparisons of sites with different protection status (more versus less protected) were used to determine the potential responses of reef fishes to the establishment of marine protected areas. Highly targeted species (top predators and large herbivores) were significantly more abundant and larger in size within sites with a higher degree of protection, indicating that they benefit from protection, while lightly fished and unfished species were not. These results are consistent with past work documenting the responses of species to protection. Here, we use our results in particular to suggest strategies and provide expectations for managing and protecting Brazilian reef fisheries. Because this biogeographic province lies entirely within the jurisdiction of a single nation, there may be unique and significant opportunities to effectively manage and conserve these fish species.  相似文献   

8.
Fish assemblages in the Mimiwhangata Marine Park, an area closed to commercial fishing but open to most forms of recreational fishing, were compared with adjacent fished areas. Two survey methodologies were used; baited underwater video and underwater visual census. Snapper (Pagrus auratus), the most heavily targeted fish species in the region, showed no difference in abundance or size between the Marine Park and adjacent control areas. When compared to the fully no-take Poor Knights Island Marine Reserve and two other reference areas open to all kinds of fishing (Cape Brett and the Mokohinau Islands), the abundance and size of snapper at the Marine Park were most similar to fished reference areas. In fact, the Marine Park had the lowest mean numbers and sizes of snapper of all areas, no-take or open to fishing. Baited underwater video found that pigfish (Bodianus unimaculatus), leatherjackets (Parika scaber) and trevally (Pseudocaranx dentex) were significantly more common in the Marine Park, than in the adjacent control areas. However, none of these species are heavily targeted by fishers. Underwater visual census found similar results with five species significantly more abundant in the Marine Park and five species more abundant outside the Marine Park. The lack of any recovery by snapper within the Marine Park, despite the exclusion of commercial fishers and restrictions on recreational fishing, indicates that partial closures are ineffective as conservation tools. The data suggest fishing pressure within the Marine Park is at least as high as at other ‘fished’ sites.  相似文献   

9.
Sex change is widespread among marine fishes, including many species that are fished heavily, and is thought to be of conservation concern under some circumstances. As such, an important question in conservation is whether the implementation of marine protected areas (MPAs), which is a commonly used marine conservation tool, works as effectively for sex-changers as for non-sex-changers. To address this issue, we used meta-analyses of the ratio of fish abundances inside vs. outside MPAs to determine whether sex change affects the extent to which fish densities respond to protection. When all data were considered, there were similar responses to protection irrespective of reproductive mode. However, when analyses were restricted to older reserves (at least 10 years’ protection), female-first sex-changers consistently benefited from protection. Non-sex-changers and male-first sex-changers showed more variable responses to protection and, as a result, there were no significant differences between fish with different reproductive modes in their overall response to protection. The same results were observed when the effects of fisheries status (targeted vs. not targeted) were controlled. Our results support the use of MPAs as important components of conservation and demonstrate that old reserves are most consistently beneficial to female-first sex-changing species. Finally, our results highlight the fact that some effects of protection are only detectable after several generations.  相似文献   

10.
The growing concern about the profound influence of human activities on marine ecosystems has been the driving force behind the creation of marine reserves in the last few decades. With almost 4200 km of coastline, Chile has not been the exception to this trend. A set of conservation priority sites has recently been proposed by the Chilean government to expand the current marine reserve network. In this study, we used the most comprehensive information currently available on the distribution of 2513 marine species in Chile to assess the efficiency of the existing system of marine protected areas (MPA) and the conservation priority sites identified by the government. Additionally, we evaluated the vulnerability of the reserve network selected with respect to threatening human activities. Our results show that both the existing protected areas and the proposed priority sites are relatively effective at protecting Chilean marine biodiversity. However, the majority of the species that are not represented within the existing or projected MPA network have very restricted distributions and are, therefore, of high conservation concern. To cover all species requires a network of 35 MPAs (46% of the total number of planning units). Many of the sites identified as irreplaceable present conflict with one or more human activities, particularly in the central region of the country. This study emphasizes the need for a systematic conservation planning approach to maximize the representation of species and prioritize those areas where conflicts between marine biodiversity conservation and human activities may occur.  相似文献   

11.
Designing conservation areas entails costs that, if considered explicitly, can be minimized while still achieving conservation targets. Here we focus on opportunity costs which measure forgone benefits from alternative land uses. Conservation planning studies often use partial estimates of costs, but the extent to which these result in actual efficiencies has not been demonstrated. Our study partitions land costs into three distinct opportunity costs to smallholder agriculture, soybean agriculture and ranching. We demonstrate that opportunity costs to single stakeholder groups can be inaccurate measures of true opportunity costs and can inadvertently shift conservation costs to affect groups of stakeholders disproportionately. Additionally, we examine how spatial correlations between costs as well as target size affect the performance of opportunity costs to single stakeholder groups as surrogate measures of true opportunity costs. We conclude that planning with opportunity costs to single stakeholder groups can result in cost burdens to other groups that could undermine the long-term success of conservation. Thus, an understanding of the spatial distributions of opportunity costs that are disaggregated to groups of stakeholders is necessary to make informed decisions about priority conservation areas.  相似文献   

12.
In managing non-native species, surveillance programmes aim to minimise the opportunity for invasions to develop from initial introductions through early detection. However, this is dependent on surveillance methods being able to detect species at low levels of abundance to avoid false-negative recordings through imperfect detection. We investigated through field experimentation the ability to detect Pseudorasbora parva, a highly invasive pest fish in Europe, in relation to their known density and sampling method. Secure pond mesocosms of area 100 m2 contained P. parva densities from 0.02 to 5.0 m−2; each density was in triplicate. These were searched using point sampling electric fishing and deployment of fish traps (non-baited and baited). No fish were captured at densities <0.5 m−2 using any method and this was considered their detection threshold. Point sample electric fishing was the least effective detection method, producing high proportions of false-negative data even at high fish densities. Baited traps were the most effective detection method. Probability of detection of P. parva was 1.0 for baited traps at all densities >0.5 m−2, whereas for electric fishing it only exceeded 0.95 at 5.0 m−2 using high searching effort. These data reveal that small pest fishes such as P. parva may be prone to imperfect detection when at low densities and this is consistent with a number of other invasive species. This indicates the importance of designing surveillance programmes using methods of known statistical power to optimise conservation resource expenditure and enhance management outcomes.  相似文献   

13.
The Marine Management Plan for the Shiretoko World Natural Heritage Site, Japan, provides a case study for adaptive marine ecosystem management and co-management of coastal fisheries. Shiretoko was the third World Natural Heritage Site registered in Japan and earned this title because of its (i) formation of seasonal sea ice at some of the lowest latitudes in the world, (ii) high biodiversity, and (iii) many globally threatened species. The natural resource management plan of the Shiretoko site is characterized by transparency and consensus building, because (i) UNESCO and IUCN require that the plan be sustainable and (ii) the Government of Japan has guaranteed local fisheries that there will be no additional regulations included in the plan. The Marine Management Plan describes which species and factors are monitored, how these data are evaluated, and how the benchmarks specified by ecosystem management are determined. The plan will provide a valuable example for the establishment of “environment-friendly fisheries” in Japan and other countries, because it includes voluntary activities by resource users that are suitable for use in a local context, flexible to ecological/social fluctuations, and efficiently implemented through increased legitimacy and compliance. This approach is appropriate for coastal communities where a large number of small-scale fishers catch a variety of species using various types of gear. We develop a method to evaluate fisheries integrity by-catch and yield data.  相似文献   

14.
Systematic approaches to site selection for marine protected areas (MPAs) are often favored over opportunistic approaches as a means to meet conservation objectives efficiently. In this study, we compared analytically the conservation value of these two approaches. We locate this study in Danajon Bank, central Philippines, where many MPAs were established opportunistically based on community preference, with few if any contributions from biophysical data. We began by identifying the biophysical data that would have been available when the first MPA was created in Danajon Bank (1995). We next used these data with the reserve selection software Marxan to identify MPAs that covered the same area as is protected under the current set of MPAs (0.32% of the total study area) and that would protect the greatest number of conservation targets at the lowest cost. We finally compared the conservation value of the current MPAs to the value of those selected by Marxan. Because of the dearth of biophysical data available in 1995 and the small area currently under protection, Marxan identified multiple configurations of MPAs that would protect the same percentage of conservation targets, with little differentiation among sites. Further, we discovered that the costs of obtaining and analyzing these data to be used for conservation planning would have been large relative to resources typically available to conservation planners in developing countries. Finally, we found that the current set of MPAs protected more ecological features than would be expected by chance, although not as many as could be protected using a systematic approach. Our results suggest that an opportunistic approach can be a valuable component of conservation planning, especially when biophysical data are sparse and community acceptance is a critical factor affecting the success of an MPA.  相似文献   

15.
Ecosystem processes in African savannas can be better conserved if management is based on a mechanistic understanding of wildlife dynamics in livestock-dominated landscapes. For Laikipia District, a non-protected savanna region in northern Kenya, we used spatially explicit estimates of density to characterize factors influencing the dynamics of large herbivores on three land-use types: commercial ranches that favor wildlife, communal ‘group ranches’ practicing pastoralism, and the remainder (‘transitional’ properties). For 21-year time series of nine wild and two domestic species, linear model selection was used to ascribe between 45% (Grant’s gazelle) and 95% (plains zebra) of observed variation in biomass density to land use, rainfall-dependence, density-dependence, and trends over time.Strongly opposing patterns of variation across the landscape in wildlife and livestock densities affirmed the primacy of land use among factors influencing wildlife abundance in non-protected areas. Rainfall limited densities of only the dominant grazing species throughout the monitoring period (plains zebra and cattle), and of most other species while their densities were high. Regulating effects of density were detected only for the dominant wild grazing and browsing species (zebra and giraffe). All but two wild species (zebra and Grant’s gazelle) declined on at least one land-use type, for reasons that varied among land uses.Where favored, diverse and abundant wild herbivores (mean of 1.7 t km−2 on pro-wildlife ranches) can thrive even when sharing the landscape with a slightly higher biomass density of livestock (mean of 2.7 t km−2). Where not favored, only a few resilient wild species (e.g. gazelles and plains zebra) persist with high densities of livestock (mean of 4.6 t km−2 on transitional ranches). Maintaining higher wild species diversity in the landscape will depend on the creation of a network of unfenced conservation areas in which livestock densities are persistently low or zero, which are sufficiently large to act as ‘sources’ of wild species that are prone to displacement by humans and livestock, and which generate benefits to community members that exceed opportunity costs.  相似文献   

16.
The US population of smalltooth sawfish, Pristis pectinata, is currently listed as endangered under the Endangered Species Act. An important component of monitoring the recovery of this species is establishing long-term baseline trends in abundance. In the absence of scientific survey data, assessing and monitoring the status of some marine species has required the utilization of fishery-dependent data. Using voluntary dockside interviews of sport fishers collected in Everglades National Park, a standardized index of abundance was created for smalltooth sawfish using the delta method. The index was developed as the product of separate generalized linear models of the proportion of positive trips and the positive catch rates on successful trips. Development of the final model included testing factors that were expected to influence the catch of smalltooth sawfish. The final model assumed a binomial distribution for the proportion of positive trips and a lognormal distribution for positive catch rates. Year was significant as a main effect in the binomial model whereas year and skill level of the fishing party were significant in the lognormal model. The relative abundance index shows a small increase in abundance at an average rate of about 5% per year since 1989. These results indicate that the population of smalltooth sawfish in Everglades National Park has at least stabilized and may be increasing. However, additional data and analyses from multiple sources are required before definitive conclusions on the recovery of smalltooth sawfish can be established.  相似文献   

17.
以基于人工鱼礁为构建主体的大亚湾海洋牧场为研究实例,以2007年4月和2009年5月调查数据为基础,研究了海洋牧场在资源养护和提高海域碳汇能力等方面的作用。结果表明,人工鱼礁型海洋牧场建设提高了海域浮游生物和底栖生物的栖息密度以及渔业资源的数量和质量,底栖生物和游泳生物的生物多样性指数增加,渔业资源优势种中的优质经济鱼类的数量增加。根据海域叶绿素浓度的提高进行计算,海洋牧场建设使海域碳汇增加了937.40kgC,相当于3.44tCO2。如果同时考虑通过渔业生物收获从海域中移出碳而增加的海域碳汇能力,则其起到的海域碳增汇能力将更高。本研究的结果表明,海洋牧场是一种环境友好型、可持续发展的低碳渔业生产模式,有利于水生生物资源养护和增殖,也是生物碳汇扩增的科学途径。  相似文献   

18.
Increasing the level of protection afforded to the marine environment requires assessment of the efficacy of existing marine protected areas (MPAs) in protecting exploited species. Long-term data from before and after the establishment of MPAs provide a rare but valuable opportunity to assess these effects. In this study we present long-term data (1977-2005) from before and after park establishment, on the abundance of spiny lobster Jasus edwardsii from fixed sites in a no-take marine park and a recreationally fished marine park, to assess the efficacy of no-take vs. partial protection. Lobster densities were comparable between both marine parks prior to park establishment, but the response of lobster populations differed markedly following protection. On average, legal-sized lobster were eleven times more abundant and biomass 25 times higher in the no-take marine park following park establishment, while in the partially protected marine park there has been no significant change in lobster numbers. Furthermore, no difference was found in densities of legal-sized lobster between the partially protected marine park and nearby fully-fished sites (<1 per 500 m2). Long-term data from fully fished and partially protected sites suggest long-term declines in lobster populations and reflect regional patterns in catch per unit effort estimates for the fishery. The long-term patterns presented provide an unequivocal example of the recovery of lobster populations in no-take MPAs, but clearly demonstrate that allowing recreational fishing in MPAs has little benefit to populations of exploited species such as J. edwardsii.  相似文献   

19.
Small-scale fisheries provide over half the world’s wild-caught seafood, employ over 99% of its fishers, and are frequently promoted as a sustainable alternative to large-scale industrial fisheries. However, few studies have quantitatively examined how possible habitat impacts and non-target species composition vary across gears used in small-scale fisheries, as data are sparse and conservation efforts are largely focused on more iconic species. Here, we quantify and compare the ecosystem impacts of four fishing gears (lobster traps, fish traps, set gillnets, drift gillnets) used in small-scale fisheries of Baja California, Mexico, using at-sea observations and field experiments. Set gillnets had the highest overall impact on both non-target species and habitat, with discard rates higher than most industrial fisheries (34.3% by weight), and an estimated 19.2% of Eisenia arborea kelp and 16.8% of gorgonian corals damaged or removed within 1 m of the net path. Fish traps had the lowest discard rates (0.11%) while lobster traps and drift gillnets had intermediate discard rates (15.1% and 18.5% respectively). In contrast with gillnets, traps caused minimal immediate damage to gorgonian corals and rarely interacted with kelp. Results indicate that ecological impacts depend more on fishing gear type and habitat characteristics than the size of fishing vessels, calling into question broad generalizations that small-scale fisheries are inherently more sustainable than industrial fisheries. Our findings highlight the ecological impacts of artisanal gillnet fisheries as priorities for research, management, and conservation efforts in Baja California and other coastal areas.  相似文献   

20.
Fishers’ attitudes and perceptions are critical for the success of fisheries protection areas with their associated biota, and a failure to understand fishers’ behaviour may undermine the success of such fisheries management measures. In this study, we examine fishers’ perception of a long-established exclusive fisheries zone around Malta and to investigate if the perceptions depend on fishers’ demographic, economic, social characteristics and fishing activity of the fishers. A questionnaire survey was undertaken to evaluate the demographic characteristics, economic situation (costs and revenue) and fishers’ activity and behaviour, together with their perception of the Fisheries Management Zone (FMZ). A total of 241 interview responses were analysed which was a response rate of 60%. The perception of most fishers was that the establishment of the FMZ has had an overall negative impact on their fishing activity and that the zone is not important for the protection of local fish stocks. When asked about the beneficial effect of the zone for fishers, most fishers from all backgrounds said that the zone does not benefit commercial fishers, but benefits mainly recreational fishers. The most evident differences in the perceptions and attitudes were between the full-time, part-time and recreational fishers. Fishers that have been fishing for more than 35 years and fishers from the main fishing village also had different attitudes from other fishers towards the FMZ. The results of this study suggest that the proportion of individual income derived from fishing was the strongest factor that influenced attitudinal differences, with home port and fishing experience having less important effects. The main differences in attitude among fishers were related to the protection and conservation effects of the zone, enhancement of resources and conflicts among user groups. The heterogeneity among fishers’ attitudes revealed by the present study has important implications for the implementation of spatial closures. Some sectors of stakeholders may require additional incentives to accept restrictions on access if spatial management is to achieve its intended objectives.  相似文献   

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