共查询到20条相似文献，搜索用时 485 毫秒
1.
Habitat use patterns of the invasive red lionfish Pterois volitans: a comparison between mangrove and reef systems in San Salvador,Bahamas 
下载免费PDF全文
下载免费PDF全文 Catalina Pimiento James C. Nifong Margaret E. Hunter Eric Monaco Brian R. Silliman 《Marine Ecology》2015,36(1):28-37
The Indo‐Pacific red lionfish Pterois volitans is widespread both in its native and its non‐native habitats. The rapid invasion of this top predator has had a marked negative effect on fish populations in the Western Atlantic and the Caribbean. It is now well documented that lionfish are invading many tropical and sub‐tropical habitats. However, there are fewer data available on the change in lionfish abundance over time and the variation of body size and diet across habitats. A recent study in San Salvador, Bahamas, found body size differences between individuals from mangrove and reef systems. That study further suggested that ontogenetic investigation of habitat use patterns could help clarify whether lionfish are using the mangrove areas of San Salvador as nurseries. The aim of the present study is to determine temporal trends in lionfish relative abundance in mangrove and reef systems in San Salvador, and to further assess whether there is evidence suggesting an ontogenetic shift from mangroves to reef areas. Accordingly, we collected lionfish from mangrove and reef habitats and calculated catch per unit effort (a proxy for relative abundance), compared body size distributions across these two systems, and employed a combination of stable isotope, stomach content, and genetic analyses of prey, to evaluate differences in lionfish trophic interactions and habitat use patterns. Our results show that populations may have increased in San Salvador during the last 4 years, and that there is a strong similarity in body size between habitats, stark differences in prey items, and no apparent overlap in the use of habitat and/or food resources. These results suggest that there is not evidence an for ontogenetic shift from mangroves to reefs, and support other studies that propose lionfish are opportunistic forages with little movement across habitats. 相似文献
2.
《Marine Policy》2016
The management of invasive species can be facilitated by public participation. The drivers of public involvement and success at invasive removal in tournaments (derbies) to catch Indo-Pacific lionfish (Pterois volitans/miles) in the Western Atlantic were examined. Information on 69 lionfish derbies held in the wider Caribbean region from 2010 to 2015 was compiled. Derbies attended mainly by artisanal fishers reported lower catches but higher participation than derbies dominated by recreational divers or attended by a mixed public. As predicted, the number of lionfish caught increased with effort and with time since lionfish were established in an area. In contrast, participation was best predicted by national wealth (GDP per capita) and number of local dive shops. From the point of view of public engagement, derbies should therefore be held in areas where lionfish are well established, and where the pool of potential participants is large. However, if the management goal is instead to slow the invasion, early detection is critical. The focus should then shift to areas where no or very few lionfish have been detected, and the derby approach modified to a more frequent or continuous, monitoring-like incentive scheme. 相似文献
3.
The Mesoamerican Barrier Reef System has considerably changed after a series of natural disturbances, especially hurricanes and extreme coral bleaching, and is further impacted by anthropogenic threats. Located at a tri-national border between Belize, Guatemala and Honduras, the Sapodilla Cayes Range is specifically impacted by tourism, commercial fishing and other anthropogenic activities occurring in the three countries and by the fact that Belize only claims 3 nautical miles of Exclusive Economic Zone in the south pending a settlement to a border dispute with Guatemala. This area represents a source of income and food to several coastal communities and to Belize's economy. Key fisheries products harvested in the area by the three countries are the same but fisheries legislations and the number of fishermen are different, creating conflicts between fishermen. This paper summarizes the key problems that arise in southern Belizean fishing waters and the efforts made by the three countries to ensure the sustainability of the fishery. 相似文献
4.
《Marine Policy》2013
There is a growing argument that the biological priorities of Europe's Common Fisheries Policy – to halt the depletion of commercial fish stocks – are not a straightforward solution to the problems currently facing international fisheries management and that social objectives need to be incorporated into policy. However, existing notions of fisheries ‘dependency’ and ‘community’ remain poorly understood and leave decision-makers struggling to address social and cultural issues. By investigating further concepts of ‘dependency’, ‘community’ and some of the social issues facing Fisheries Dependent Areas in Scotland, this research explores the complex shape of coastal fishing communities and the conditions of dependency on fishing that coastal areas face. In this paper preliminary findings from an in-depth case study of Fraserburgh in the north east of Scotland are presented to explore the potential meaning and justification of social objectives in fisheries policy. 相似文献
5.
《Marine Policy》2014
Fishing communities are subject to economic risk as the commercial fisheries they rely on are intrinsically volatile. The degree to which a community is exposed to economic risk depends on a community׳s ability to confront and/or alter its exposure to volatile fishery conditions through risk-reduction mechanisms. In this article, economic risk – as measured by community-level fishing gross revenues variability – is characterized across Alaskan fishing communities over the past two decades, and exploratory analyses are conducted to identify associations between community attributes and revenues variability. Results show that communities’ fishing portfolio size and diversification are strongly related to fishing revenues variability. Communities with larger and/or more diverse fishing portfolios experience lower fishing revenues variability. Portfolio size and diversification appear to be related to the number of local fisheries, indicating that communities’ portfolios may be constrained to the set of local fisheries. Hotspots of relatively higher fishing revenues variability for communities in north and west Alaska were identified, mirroring the spatial distribution of fishery-specific ex-vessel revenues variability. This overall pattern suggests that a community׳s fishing portfolio – and hence its exposure to risk – may be “predetermined” by its location, thereby limiting the policy options available to promote economic stability through larger and/or more diverse fishing portfolios. For such communities, diversifying income across non-fishing sectors may be an important risk reduction strategy, provided any potential negative cross-sector externalities are addressed. 相似文献
6.
《Ocean & Coastal Management》2007,50(8):683-698
Illegal, unreported and unregulated (IUU) fishing activities continue to thrive in the northern region of Australia's Fishing Zone (AFZ). Indonesian fishermen involved in IUU fishing in this area target specific marine species such as shark, reef fish, sea cucumber and trochus that are destined for the Asian market. Many of these marine species’ stocks are now at critical levels. Local communities based in Northern Australia, state and Federal governments are also concerned with issues of border security and quarantine measures that coincide with the IUU fishing activities. Whilst Australian and Indonesian governments continue to negotiate this pressing issue, international instruments, bilateral agreements and domestic policies are not deterring Indonesian fishermen from pursuing IUU fishing activities in the AFZ. 相似文献
7.
《Ocean & Coastal Management》2006,49(7-8):476-497
Fisheries management systems everywhere tend to be dominated by the proprietary claims of nation states. These claims are embodied in a number of international agreements such as the United Nations’ Convention on the Law of the Sea, which accords rights to nation-states on the basis of adjacency and historic use. In this paper, we present results from research in Nova Scotia, Canada, to demonstrate that small boat fishing families in that region have been continuously fishing the grounds adjacent to their communities for many generations, but must now fish those areas on the basis of a state-granted ‘privilege’ rather than a secure right. In this paper we argue that the principles of adjacency and historic use should apply to individuals and fishing families and that states should move towards a more community-determined approach to fisheries management. The lobster fishery of Northeastern Nova Scotia provides a particularly compelling example of how this type of change in management policy could be successfully accomplished. 相似文献
8.
Habitat degradation and fishing are major drivers of temporal and spatial changes in fish communities. The independent effects of these drivers are well documented, but the relative importance and interaction between fishing and habitat shifts is poorly understood, particularly in complex systems such as coral reefs. To assess the combined and relative effects of fishing and habitat we examined the composition of fish communities on patch reefs across a gradient of high to low structural complexity in fished and unfished areas of the Ningaloo Marine Park, Western Australia. Biomass and species richness of fish were positively correlated with structural complexity of reefs and negatively related to macroalgal cover. Total abundance of fish was also positively related to structural complexity, however this relationship was stronger on fished reefs than those where fishing is prohibited. The interaction between habitat condition and fishing pressure is primarily due to the high abundance of small bodied planktivorous fish on fished reefs. However, the influence of management zones on the abundance and biomass of predators and target species is small, implying spatial differences in fishing pressure are low and unlikely to be driving this interaction. Our results emphasise the importance of habitat in structuring reef fish communities on coral reefs especially when gradients in fishing pressure are low. The influence of fishing effort on this relationship may however become more important as fishing pressure increases. 相似文献
9.
《African Journal of Marine Science》2013,35(2):269-281
Fish were surveyed by visual census on offshore reefs in Mozambique and eastern South Africa to compare (a) fully-protected ‘sanctuary’ areas, (b) ‘partly protected’ areas where recreational diving and limited fishing are permitted, and (c) ‘open’ unprotected areas. Community composition differed between coral-dominated reefs and those covered mainly by algae and sponges, but not among treatments. Larger size classes were significantly diminished in unprotected areas compared to protected and sanctuary zones. Within coral-dominated reefs, abundances of indicator taxa showed three patterns: (1) greatest abundance in sanctuaries, intermediate in partly protected and least in open areas; (2) greatest abundance in sanctuaries but equal diminishment in partly protected and open areas; and (3) greater depletion in partly protected than either sanctuary or open areas. We conclude that partial protection does not effectively conserve reef fish, and there are indications that partly protected areas concentrate fishing effort on ‘pelagic’ gamefish. Sanctioned shore-angling and offshore ‘gamefishing’, illegal fishing and diver disturbance may collectively undermine the efficacy of partially protected areas. The depletion of reef fish species inside protected areas and reconsideration of the classification of pelagic gamefish require managerial attention. Partly protected areas in Mozambique need to be supplemented with no-take zones. 相似文献
10.
Spatial discordance in fish,coral, and sponge assemblages across a Caribbean atoll reef gradient 下载免费PDF全文
下载免费PDF全文 Certain biodiversity patterns on coral reefs are generally consistent but we still lack fundamental insight into how assemblages vary across spatially heterogeneous reef systems. We compared fish, coral, and sponge assemblages across a symmetrical physiographical gradient (windward forereef, lagoon patch reef, leeward forereef) of the Glover's Reef atoll, Belize. Species richness of fishes and corals was highest in the deep habitat (15 m) on the windward forereef. Sponges were diverse and abundant on both deep windward and leeward forereefs but not on the exposed shallow (5 m) windward forereef. Fish and benthic assemblages were relatively distinct in each reef zone, with the lagoon patch reef communities consisting of a combination of leeward and windward species. Nevertheless, there were no clear patterns in community similarity matrices of fish and benthic assemblages, suggesting that overall coral and sponge assemblages had weak or no direct association with patterns in fish assemblages. A closer examination of fish trophic groups indicated that planktivores and predators were predictably associated with depth, whereas herbivores were associated with shallow protected reefs. None was specifically associated with spatial location along the atoll gradient. These patterns of diversity distribution are important for identifying spatial conservation priorities. A Marine Protected Area (MPA) at Glover's Reef encompasses substantial windward forereef and patch reef habitats. A much lesser extent of protection is afforded the leeward forereef that supports faunal assemblages that are unique and productive, if not as diverse as the windward forereef. Isolated coral atolls can serve as ideal systems to study spatial heterogeneity and biodiversity patterns, but more experimental studies are needed to reveal the mechanistic processes underlying these patterns. 相似文献
11.
对三重双向嵌套海洋环流三维数值模型系统(CANDIE),用尤卡坦海峡实测横断面流速和海温等值线、1990年代根据卫星跟踪漂移轨迹推求得到的15m水深处的时间平均流场、实测平均海温过程和西加勒比海体积输送流函数等资料进行了验证,结果表明所建三重双向嵌套模型系统结构与参数合理,模型能较好地模拟西加勒比海的环流特征如加勒比流、巴拿马-哥伦比亚漩涡和该地区温盐的季节性变化。模型被用来计算小模型计算域(伯利兹大陆架)珊瑚礁地区不同水深处悬浮颗粒的运动轨迹线、颗粒的保留与耗散。近表层耗散在Lighthouse Reef Atoll和Glovers Reef Atolls以东相对较强,在内大陆架特别在Inner Channel内和South Water Cay附近相对较低。为了测试伯里兹大陆架海表面珊瑚礁之间的水动力连接特性,计算了位于Turneffe Islands Atoll和GloversReef Atolls珊瑚礁的上游颗粒来源区(源)和下游颗粒耗散区(汇),在30天内到达这两处环形珊瑚礁的近表面颗粒的可能来源区包括该两者周围的浅水区域、两者之间的深水区域和洪都拉斯Bay Islands的沿岸水域,Turneffe和Glovers Reef Atolls 30天下游耗散区分别覆盖了伯里兹大陆架的中部和南部水域。 相似文献
12.
T Sancelme J Goetze S Jaquemet MG Meekan A Flam AM Watts 《African Journal of Marine Science》2020,42(1):95-107
Coastal populations of maritime countries in eastern Africa rely on fish as a primary source of protein, but baseline information on the abundance of fish communities on these coastlines is often lacking. We used baited remote underwater video stations to compare the abundance and diversity of reef fishes targeted by fishing at two sites in southern Mozambique, one at Lighthouse Reef within the Bazaruto Archipelago National Park and the other to the south at San Sebastian Reef on the San Sebastian Peninsula. Fish that are known targets of fisheries (mostly small-scale and artisanal) had an abundance that was almost three-times greater at San Sebastian Reef (80.22 ind. h–1 [SE 18.00]) than at Lighthouse Reef (29.70 ind. h–1 [SE 8.91]). Similarly, there was greater mean species richness at San Sebastian Reef (38.74 species h–1 [SE 2.79]) than at Lighthouse Reef (25.37 species h–1 [SE 3.66]). The main drivers of targeted fish abundance were habitat and depth, with shallow (<15 m) and mixed reef areas having the greatest abundance and richness. More sampling was done over sand habitat at Lighthouse Reef, which likely led to the lower abundance and species richness observed at this site; however, that finding could also be attributable to the fact that protection is provided to only a section of available coral reef habitat in a small area. Nevertheless, fish community structure was comparable between the sites, with similar proportions of carnivores (78–81%), herbivores (12–14%) and omnivores (7–8%). Our findings highlight the variation in species abundance and assemblages of coral-reef fish targeted by fishing in Mozambique and emphasise the importance of localised environmental variables as a driver of these patterns. To ensure maximum protection of Lighthouse Reef fish communities, we recommend an extension of the no-take zone to include the entire reef complex. 相似文献
13.
As coral reef ecosystems decline in health worldwide, reef‐associated fishes are being impacted by changes to their coral reef habitats. While previous studies have shown coral reef structure to affect the demography of reef fishes, changes in reef conditions may also impact the behavior of reef fishes as they cope with altered habitats. In this study, we examined spatial patterns of intraspecific behavioral variation in the bicolor damselfish (Stegastes partitus) across the fringing reefs of Curaçao (Caribbean Sea), and explored how this behavioral variation associated with physical and social conditions on the reef. Principal components analysis (PCA) condensed physical parameters of the reef into principal component 1 (PC1), comprising depth, coral cover (%), rugosity, and average hole size (cm2), and principal component 2 (PC2), which represented the number of holes. PC1, but not PC2, increased spatially across the reef as the habitat transitioned from coral rubble in the shallows to live coral on the reef slope. This transition in reef structure was paralleled by changes in social conditions including decreases in bicolor damselfish density in habitats with higher PC1 values. The behavior of bicolor damselfish also varied spatially with greater aggression and more frequent shelter use in habitats with lower PC1 values. Path analysis revealed robust associations between this behavioral variation and physical habitat conditions of the reef, indicating that physical – rather than social – habitat variation is the primary determinant of these spatial patterns of intraspecific behavioral variation. Taken as a whole, this coupling between physical reef structure and behavior suggests that reef fish may show altered behaviors on coral reefs degraded by anthropogenic impacts. 相似文献
14.
《Marine Policy》2017
Coral reefs provide important ecological services such as biodiversity, climate regulation, and cultural benefits through recreation and tourism. However, many of the world's reefs are declining, with Caribbean reefs suffering a significant decline in living corals over the past half century. This situation emphasizes the need to assess and monitor reef conditions using a variety of methods. In this study, a new method for assessing reef conditions to inform management using participatory mapping by coral reef “experts” in the U.S. Virgin Islands (USVI) is described. Occupational SCUBA divers were recruited (n=87) to map coral reef conditions, uses, and threats (stressors) using an internet-based mapping website. The data reveal an uneven geographic distribution of reef conditions in the USVI with the most frequently mapped perceived healthy reef characteristics being: large amount of physical reef structure (n=872 markers); endangered or threatened species present (n=721); and large amount of live coral cover (n=615). The greatest perceived threats were: invasive species (n=606); water pollution (n=234); and unsustainable fishing (n=200). Areas of important reef characteristics, perceived threats to reefs, and perceived recovery potential were plotted to identify areas requiring critical management attention. The authors found that perceptions of healthy reef conditions outnumbered perceptions of reef threats for nine of the ten most familiar coral reefs; the most frequent activity type within the coral reefs was tourism diving; and for the most familiar coral reefs, the divers perceived a high recovery potential. Given the novelty of participatory mapping methods to assess coral reefs, the strengths and weaknesses of the method is evaluated. The authors further propose a management typology for categorizing reef areas to inform their future management. In the absence of primary data, or, as a supplement to underwater surveys and remotely-sensed data on reef condition, participatory mapping can provide a cost-effective means for assessing coral reef conditions while identifying place-specific reef locations requiring management attention. 相似文献
15.
《African Journal of Marine Science》2013,35(3):277-287
Standardised sampling protocols for monitoring fish stocks are essential to assess changes in stock status and provide a means to evaluate the effectiveness of fisheries management measures, such as marine protected areas (MPAs). This study aimed to optimise two standard sampling methods, namely underwater visual census (UVC) and controlled angling, for assessing subtidal reef fish communities. In terms of efficiency, variability and bias, UVC transects were found to be superior to point counts. For controlled angling, an effort of two angler-hours per fishing station provided low catch variability, high catch per unit effort and a representative catch. Whereas UVC provided less variable estimates of relative density, controlled angling provided greater sampling efficiency. It is thus recommended that the two methods be used in conjunction. The optimal sampling protocols identified are suitable for rapid assessments or long-term monitoring of subtidal, temperate reef fish communities. 相似文献
16.
ML Camara B Mérigot F Leprieur JA Tomasini I Diallo M Diallo 《African Journal of Marine Science》2016,38(2):189-206
In a context of growing fishing pressures and recommendations for an ecosystem approach to fisheries, there is a need to monitor changes in fish communities over time. In this study, we analysed data from scientific trawl surveys carried out on the continental shelf off Guinea between 1985 and 2012. We performed factorial analyses and calculated biodiversity indices to characterise the changes in the structure and composition of fish communities that occurred over the 28-year period in this area, particularly given intensive fishing activities. We show that, over the study period, fish communities on the Guinean shelf were structured primarily according to spatial factors, with temporal changes being less pronounced than expected. However, a temporal analysis of biodiversity indices and species dominance showed that the intensification of fishing had significant effects on the general ecological features of the fish assemblages under study. There was a decrease in fish density and in mean trophic level. In addition, there were changes in species dominance, whereby large, slow-growing species with high commercial value were gradually replaced by smaller, fast-growing species of lesser commercial interest. These results from field observations are in line with some conclusions from previous modelling studies in the same geographical area, and provide further support for the hypothesis of a progressive ‘ecosystem effect of fishing’ occurring in Guinean waters. 相似文献
17.
《Marine Policy》2017
Groupers are highly targeted and vulnerable reef fishes. The effects of fishing pressure on the density of three reef fishes were investigated in 21 islands outside (n=15) and inside (n=6) a Marine Protected Area (MPA) at the Paraty Bay, Brazilian southeastern coast. Two valued groupers (Epinephelus marginatus and Mycteroperca acutirostris) and a non-target grunt (Haemulon aurolineatum) were studied. The total biomass of fish caught in each island was considered as a measure of current fishing pressure, while the island distance from the villages was considered as a measure of past fishing pressure. Fish densities were recordedin number and biomass. The biomass of M. acutirostris was inversely related to current fishing pressure, which did not affect the other two fishes. The density of E. marginatus increased with the island distance from one of the fishing villages, which indicated that past fishing may have had decreased the abundance of E. marginatus. Densities of the three fishes and fishing pressure did not differ between islands inside and outside the MPA. Data on fishing pressure, densities of groupers and coral cover were combined here to assign conservation scores to islands. A redefinition of MPA boundaries to reconcile fish conservation, fishing activities and fishers’ food security was proposed. 相似文献
18.
《Marine Policy》2013
Conflict surrounding commercial fisheries is a common phenomenon when diverse stakeholders are involved. Harvesting reef fish for the global ornamental fish trade has provoked conflict since the late 1970s in the State of Hawaii. Two decades later the state of Hawaii established a network of marine protected areas (MPAs) on the west coast of the island of Hawaii (“West Hawaii”) to protect and enhance the fish resources and alleviate conflict between stakeholders, principally between commercial dive tour operators and aquarium fishers. The perceptions held by these stakeholders on West Hawaii and Maui were evaluated to understand how MPAs influenced conflict dimensions, as the former location had a well-established MPA network designed to alleviate conflict, while the latter did not. This was accomplished by analyzing the following questions: (1) perceptions about the effectiveness of MPAs to alleviate conflict and enhance reef fish; (2) perceived group encounters and threats to coral reefs; (3) willingness to encourage fishing; and (4) value orientations toward the aquarium fish trade. The results indicate the MPAs in West Hawaii were moderately effective for alleviating conflict, encounters between stakeholders occurred on both islands, dive operators strongly opposed commercial fishing and perceived aquarium fishing as a serious threat to the coral reef ecosystem, and polarized value orientations toward the aquarium fish trade confirms pervasive social values conflict. The conflict between these groups was also asymmetrical. MPAs are inadequate for resolving long term conflict between groups who hold highly dissimilar value orientations toward the use of marine resources. Future marine spatial planning and MPA setting processes should include stakeholder value and conflict assessments to avoid and manage tensions between competing user groups. 相似文献
19.
P.M. Chittaro P. Usseglio B.J. Fryer P.F. Sale 《Estuarine, Coastal and Shelf Science》2006,67(4):673-680
Lutjanus apodus (Schoolmaster) were collected from several mangroves and coral reefs at Turneffe Atoll, Belize, in order to investigate whether elemental concentrations from the otolith edge could be used as a means to identify the habitat (mangrove or coral reef) and site (9 mangrove sites and 6 reef sites) from which they were collected. Results of a two factor nested MANOVA (sites nested within habitat) indicated significant differences in elemental concentrations between habitats (i.e., mangrove versus reef) as well as among sites. When separate Linear Discriminant Function Analyses (LDFA) were used to assess whether the spatial variability in otolith chemistry was sufficient to differentiate individuals to their respective habitats or sites, the results indicated that fish were classified (jackknife procedure) with a moderate to poor degree of accuracy (i.e., on average, 67% and 40% of the individuals were correctly classified to the habitat and site from which they were collected, respectively). Using a partial Mantel test we did not find a significant correlation between the differences in otolith elemental concentrations between sites and the distance between sites, while controlling the effect of habitat type (mangrove or reef). This suggests that for mangrove and reef sites at Turneffe Atoll, Belize, the overlap in terms of L. apodus otolith elemental concentrations is too high for investigations of fish movement. Finally, by comparing previously published Haemulon flavolineatum otolith chemistry to that of L. apodus we assessed whether these species showed similar habitat and/or site specific patterns in their otolith chemistry. Although both species were collected from the same sites our results indicated little similarity in their elemental concentrations, thus suggesting that habitat and site elemental signatures are species specific. 相似文献
20.
The South African coastline has been invaded by numerous alien species. Rare pre-invasion (1980) and post-invasion datasets (2001 and 2012) exist for Marcus Island, a small land-tied island in Saldanha Bay, South Africa. These snapshot datasets of the island’s intertidal invertebrate community were complemented with monitoring across seasons, from 2014 to 2016. Invertebrate communities were compared among the summers of 1980, 2001, 2012, 2014, 2015 and 2016 to assess interannual differences, while invertebrates and algae were monitored quarter-annually to assess seasonal changes. In addition, the population dynamics of the alien mussel Mytilus galloprovincialis were monitored. Differences in invertebrate communities between consecutive summers were significant but much smaller than changes induced by the arrival of alien species. Invertebrate and seaweed communities differed among years and shore zones but not among seasons, whereas species diversity differed among years, seasons and shore zones, with zones having the strongest influence. The invasion by M. galloprovincialis, and ensuing spatial and temporal variability in its recruitment, emerged as the most important factor influencing community composition, overshadowing interannual and seasonal changes. This work highlights that the impacts of alien species can be distinguished from natural variability by combining long-term monitoring with surveys at finer temporal scales. This is an important step in extending our understanding of the impacts of marine alien species. 相似文献