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1.
In this study, we sought to investigate the biology (diet and reproduction) and ethnobiology (fishers knowledge and fishing spots used to catch snappers) of five species of snappers (Lutjanidae), including Lutjanus analis, Lutjanus synagris, Lutjanus vivanus, Ocyurus chrysurus, and Romboplites saliens at five sites along the northeast (Riacho Doce, Maceió in Alagoas State, and Porto do Sauípe, Entre Rios at Bahia State) and the southeast (SE) Brazilian coast (Paraty and Rio de Janeiro cities at Rio de Janeiro State, and Bertioga, at São Paulo State.). We collected 288 snappers and interviewed 86 fishermen. The stomach contents of each fish were examined and macroscopic gonad analysis was performed. Snappers are very important for the fisheries of NE Brazil, and our results indicated that some populations, such as mutton snapper (L. analis) and lane snapper (L. synagris), are being caught when they are too young, at early juvenile stages. Local knowledge has been shown to be a powerful tool for determining appropriate policies regarding management of target species, and artisanal fishermen can be included in management processes. Other suggestions for managing the fisheries are discussed, including proposals that could provide motivation for artisanal fishermen to participate in programs to conserve resources, such as co-management approaches that utilize local knowledge, the establishment of fishing seasons, and compensation of fishermen, through 'payment for environmental services'. These suggestions may enhance the participation of local artisanal fishermen in moving to a more realistic and less top-down management approach of the fish population.  相似文献   

2.
赵旭  向恒星  赵菲菲 《生态学报》2024,44(5):1854-1867
渔民作为长江十年禁渔的参与主体,其后续生计发展将直接决定此生态保护政策的实施成效。在重构非自愿生态移民生计脆弱性评价体系的基础上,结合长江流域重点禁渔水域典型退捕渔民的抽样数据,测度渔民生计脆弱性指数(LVI)并找出影响后续生计恢复的主要障碍因子,最后跨领域的引入支持向量回归(SVR)预测模型动态分析了不同区域渔户生计脆弱性的演变趋势。结果表明:(1)渔民弃船上岸后呈现出生计脆弱性的比例较高,但不同类型区域间存在明显差异,其中内湖保护区最高,干流非保护区次之而干流保护区最低;(2)敏感性维度在诱发渔民生计脆弱性上起着主导作用,即个体禀赋比安置区条件更为重要,特别是成员年龄大但无基本社保兜底,受教育程度低且"双转"难的渔民家庭更易陷入生计困境;(3)自然和金融资本是推动渔民生计恢复的主要生计资本,而阻碍渔民生计脆弱性降低的共性因子主要有上岸后的收支失衡,社会支持不足及过分依赖原有生计方式等,同时各区域在脆弱性各维度上还有特殊的障碍因子;(4)推动安置区经济社会发展和家庭转产增收后,并不一定能确保缓解未来五年中的渔户生计脆弱性程度,上岸后完成社会融入并有效降低生产生活成本也至关重要,而干流保护区则还需加强人力资本建设,否则后续将面临极高的返贫风险;(5)长江临近区域的同类渔民生计脆弱性现状、面临的生计风险、后续生计恢复的进程具有一定的相似性和规律性,生计监测和帮扶政策可进行协同统筹。  相似文献   

3.
气候变化对渔区感知指数、生计策略和生态效应的影响   总被引:1,自引:0,他引:1  
气候变化已对全球海洋生态环境产生了直接影响,并对渔业资源、渔业生产与渔户生计造成巨大的负面影响,而渔户也通过生计适应影响海洋生态环境。迄今为止,关于渔户对气候变化的感知、生计适应及其生态效应的研究成果较少,基于家庭调查的实证研究更鲜见于报道。选取中国东南沿海的一个典型渔区——福建省霞浦县牙城镇,采用参与式农村评估法(Participatory Rural Appraisal,PRA),基于158份渔户家庭的有效数据,构建气候变化影响感知指数,揭示气候变化影响感知指数与生计资本的内在关联,并进一步探究渔户的生计适应策略及其产生的生态效应。结果表明:(1)渔户对气候变化及其影响的感知较为强烈;(2)渔户的气候变化影响感知指数与生计资本呈现一定的相关性;(3)渔户主要调整了生计生产方式和多样化收入经营两方面策略;(4)渔户生计适应策略的调整会对海洋生态环境产生正面和负面的影响。在此基础上,提出保护渔户生计安全、防范气候变化风险、保护海洋生态环境的政策建议,为当地及其他典型渔区更好地应对气候变化提供有益参考。  相似文献   

4.
The colour of seawater is a topic of daily discussion among diver fishermen in the Dominican Republic, who navigate shifting ocean environments alongside conservation politics. While conservation policies often target fishing as the main cause of declines in the health of marine ecologies, fishermen use colour to create alternative narratives about changing climates. Describing the sea as blue, black, brown, green, whitewash, purple, and chocolate, divers point to the broader causes of shifting seascapes while chronicling their affective and embodied consequences. Based on ethnographic fieldwork among Dominican diver fishermen, this article explores the colour of seawater as a lens for understanding the physical, affective, social, and political consequences of changing climates for communities who are deeply entangled in shifting sea ecologies. For diver fishermen, whose engagements with the sea depend on visibility, colours provide ways of interpreting fishing possibilities, navigating ocean spaces, and measuring the effects of changing environments. Given the centrality of colour perception in fishermen's lives, this article argues that colours provide an alternative narrative about changing climates, linking shifting marine conditions to global systemic problems, rather than blaming changes in environmental conditions on supposedly irresponsible practices of local people.  相似文献   

5.
The scarcity of dugong (Dugong dugon Miiller) throughout their former range and lack of knowledge of the species' ecology justifies this record of the opinions of the fishermen in the Lamu district of Kenya, where the species is still plentiful. The area and the programme of questioning are described. The social life, reproduction, movements and predators of the dugong are recorded as reported by the fishermen. The present distribution is contrasted with the past. My observations on the food plants and their distribution are given, as well as the fishermen's estimation of the part each plays in the dugong's diet. The need for calm water over feeding grounds, afforded by depth of water or shelter from winds, seems to be a controlling factor in the distribution of dugong. Man appears to be the main predator.  相似文献   

6.
Ecological baselines are disappearing and it is uncertain how marine reserves, here called fisheries closures, simulate pristine communities. We tested the influence of fisheries closure age, size and compliance on recovery of community biomass and life-history metrics towards a baseline. We used census data from 324 coral reefs, including 41 protected areas ranging between 1 and 45 years of age and 0.28 and 1430 km2, and 36 sites in a remote baseline, the Chagos Archipelago. Fish community-level life histories changed towards larger and later maturing fauna with increasing closure age, size and compliance. In high compliance closures, community biomass levelled at approximately 20 years and 10 km2 but was still only at approximately 30% of the baseline and community growth rates were projected to slowly decline for more than 100 years. In low compliance and young closures, biomass levelled at half the value and time as high compliance closures and life-history metrics were not predicted to reach the baseline. Biomass does not adequately reflect the long-time scales for full recovery of life-history characteristics, with implications for coral reef management.  相似文献   

7.
Dusky grouper (garoupa, Epinephelus marginatus) is an important catch for several artisanal small-scale fisheries along the Brazilian coast. It is a sedentary, monandric, and late maturing protogynous species, which makes it vulnerable to overharvesting even though it is mainly caught through hook and line or spear fishing through free diving. Lack of information on the ecology and biology of this species in Brazil is astonishing. Much of the information found in the literature concerns Mediterranean dusky groupers. Studies compiling local knowledge (ethnoecology) about fish species complement biological data, and have been fundamental for effective fisheries management. In this study, our objectives are to obtain data about dusky grouper through fish catches and analysis of stomach contents and gonad maturation (macroscopic analyses), along with interviews from fishermen from six small-scales communities from the southern (Pântano do Sul, Florianópolis, Santa Catarina State) to the northern Brazilian coast (Porto Sauípe, Bahia State). We conclude that precautionary approaches and 'data-less' management approaches are needed in the coast of Brazil. Research on this species and on the potential of aquaculture for its cultivation, are urgent, due to the apparent vulnerability and decrease of dusky grouper along the coast of Brazil.  相似文献   

8.
Bolbometopon muricatum, the largest species of parrotfish, is a functionally important species that is characterised by the formation of aggregations for foraging, reproductive, and sleeping behaviours. Aggregations are restricted to shallow reef habitats, the locations of which are often known to local fishers. Bolbometopon muricatum fisheries are therefore vulnerable to overfishing and are likely to exhibit hyperstability, the maintenance of high catch per unit effort (CPUE) while population abundance declines. In this study, we provide a clear demonstration of hyperstable dynamics in a commercial B. muricatum fishery in Isabel Province, Solomon Islands. Initially, we used participatory mapping to demarcate the Kia fishing grounds into nine zones that had experienced different historic levels of fishing pressure. We then conducted comprehensive underwater visual census (UVC) and CPUE surveys across these zones over a 21-month period in 2012–2013. The individual sites for replicate UVC surveys were selected using a generalised random tessellation stratified variable probability design, while CPUE surveys involved trained provincial fisheries officers and local spearfishers. A comparison of fishery-independent abundance data and fishery-dependent CPUE data indicate extreme hyperstability, with CPUE maintained as B. muricatum abundance declines towards zero. Hyperstability may explain the sudden collapses of many B. muricatum spear fisheries across the Pacific and highlights the limitations of using data-poor fisheries assessment methods to evaluate the status of commercially valuable coral reef fishes that form predicable aggregations.  相似文献   

9.
A decline in bluefish (Pomatomus saltatrix L.) recreational landings during the 1990s and the early 2000s led to multiple theories on the ultimate cause. One theory was that a large portion of the bluefish population moved offshore and was unavailable to nearshore recreational fishers; one reason given for the movement offshore was increased competition with striped bass (Morone saxatilis W.). We conducted laboratory experiments (feeding and non-feeding) to examine behavioral interactions between adult bluefish and sub-adult striped bass in a large (121,000 L) research aquarium. Additionally, we examined diet and habitat overlap of bluefish and striped bass from the fall and spring bottom trawl surveys conducted by the National Marine Fisheries Service. Observations of feeding trials for the following treatments were made: non-impaired (i.e., same number and size of bluefish and striped bass), size-impaired (i.e., large striped bass/small bluefish), number-impaired (i.e.,10 striped bass/3bluefish), and single-species controls. Within a species, there was no difference in a variety of behavioral measures (e.g., attack rate, capture success, ingestion rate, and activity) between mixed- and control treatments under non-impaired or size-impaired conditions. However, behavior of number-impaired bluefish differed from control and size-impaired fish suggesting that striped bass may have a negative influence on bluefish foraging when bluefish are “out-numbered”. Feeding had a strong effect on swimming speeds for both species. Diet and habitat overlap between bluefish and striped bass in continental shelf waters was low. Overall, foraging behavior in mixed-species treatments and field observations suggest no competitive interactions between adult bluefish and sub-adult striped bass.  相似文献   

10.
The jaraquis (Semaprochilodus spp.) are the most abundant group in the fishing landing in Manaus. However, just command and control management strategies have been used by the fishery governmental agency in the region without the power to enforce centralized decisions. The fishermen and their culture represent a source of information on dynamics of the resources and aquatic environments, fundamental in making possible the co-management of the fishing resources. The present study aims to contribute to management through identification of common information available in scientific and traditional knowledge about the jaraquis' bio-ecology. There were 57 semi-structured interviews recorded with fishermen of Manaus and rural areas of Manacapuru in 2002 concerning biological and ecological aspects. Similarity was observed between scientific and traditional knowledge in the following items: size of first sexual maturation, spawning type, parental care, trophic relationships and migratory behavior, as well as in some aspects of the mortality and growth of the species. However, there was less ethnoicthyological information on fecundity and the determination of the age and growth of adult fish. Common information would be used preferably by agencies to start an effective and technical dialogue with commercial and riverine fishermen to design management plans in a decentralized strategy.  相似文献   

11.
Marine Protected Areas (MPAs), if well designed and managed, can produce conservation benefits to fish assemblages within no-take zones and fishery benefits in neighboring areas through ‘spillover’. However, although plenty of studies have provided evidence of the benefits produced within MPA boundaries, overall benefits to local fisheries, especially via spillover, seem to be still unclear. Because of the lost fishing grounds following an MPA establishment, local fishermen usually oppose MPAs. There is, therefore, the urgent need for a better understanding of the mechanism(s) through which MPAs can export fishable fish biomass towards adjacent fished areas, a process that could counterbalance the loss of fishing grounds. Here we review the literature on spillover for refining the terminology, detailing the underlying mechanisms and identifying both the existing and needed methodological approaches to measure spillover. Operationally, two types of spillover should be considered: ecological spillover (i.e. the net export of juvenile, subadult and adult biomass from MPAs outwards driven by density-dependent processes) and the fishery spillover (i.e. the proportion of this biomass that can be fished, taking into account regulations and accessibility). Underwater visual census and tagging/tracking may allow getting evidence of ecological spillover, while experimental catch data are essential to assess and monitor fishery spillover, which is the main component of MPAs that can provide direct benefit to local fisheries.  相似文献   

12.
Fishermen’s local knowledge of fishing resources may be an important source of information to improve artisanal tropical fisheries management, such as those found in Brazil, where most data on fish biology is lacking. We aim to study the local ecological knowledge that Brazilian coastal fishers have about reproductive aspects (season, places and migration) of 13 coastal fish species of commercial importance. We selected fishermen with more than 30 years of fishing practice and we interviewed a total of 67 fishermen: 29 from the southeastern coast, from the communities of Puruba, Almada, Picinguaba and Bertioga, and 38 from the northeastern coast, from the communities of Valença, Arembepe and Porto Sauípe. In the interviews, we used standardized questionnaires and showed photos of fish species. Our results indicate some general patterns in fishes’ reproduction according to fishermen knowledge: fish species spawn in open ocean, near reefs or in coastal rivers (estuaries); some fishes reproduce during the summer and others in winter, while some have more defined spawning months. The main fish migratory patterns mentioned by interviewees were: long migrations along the coast, usually in the South to North direction, short migrations among reefs, fishes that do not migrate, migrations between the shore and open ocean and migrations between the sea and coastal rivers. Fishermen’s knowledge differed among fish species: most fishermen did not know spawning places or seasons of large pelagic fishes, which raised concerns of their possible depletion. We compared such ethnoichthyological information with available scientific data, indicating promising insights about reproduction and migration of Brazilian coastal fishes. Data gathered from local fishermen may provide inexpensive and prompt information, potentially applicable to fisheries management. Our approach might be useful to several other small-scale fisheries, especially the tropical ones, where there is a high diversity of target species and a low biological and ecological knowledge about these species.  相似文献   

13.
14.
Thirteen river basins draining into the Marmara, Aegean and Mediterranean Seas were selected for evaluation of European eel (Anguilla Anguilla L., 1758) catch in Turkey. These basins were grouped into three so-called “eel monitoring area” (EMA). The official province-based annual landing data between 1996 and 2018 were assessed for each of the monitoring areas. Statistically significant decreases over the years were observed in the landing data in all of the monitoring areas. The adequate protection of the European eel standing stocks, particularly in some critical eel habitats such as Köyceğiz lagoon showed over time a small decrease in eel catches in EMA-2. However, a substantial decrease was detected in the province of Adana, which includes the Seyhan and Ceyhan basins, and these are located in the EMA-3. The catch data mainly based on the commercial fisheries and the restriction on export seems to be the main reason for the decline in catches in the three EMAs. Thus the suggested monitoring areas (EMAs) are needed to structure research programmes on basic knowledge on escapement ratio of migrating silver eels, arrival and upstream migration of glass eels in the rivers of each of the EMAs in order to build area specific management strategies. These monitoring areas may provide practical units that management can use in future fisheries regulations.  相似文献   

15.
African tilapias (Oreochromis spp.) occur in more than 100 countries outside of their native ranges and research on their invasions is largely lacking. We investigated spatiotemporal patterns of tilapia spread into 29 drainage basins in Belize and parts of Guatemala and Mexico, drawing on field data and interviews with fishermen. Habitat-suitability models for tilapias were created from geospatial and species occurrence data, and fishermen interviews were used to reconstruct the chronology of tilapia spread into predicted suitable habitats. Tilapia (predominantly Nile tilapia, O. niloticus) presence was confirmed at 78 sites in 9 of 29 drainage basins. Our habitat-suitability model predicted that 7,510 linear km of river habitat in the study area were vulnerable to colonization by tilapias, predominately in mid- to low elevation main stem rivers, from sea level to 277 m above sea level. The reconstructed spatial chronology of spread showed that the invasion started in 1990 and progressed slowly (2 km yr?1) through an establishment phase before rapid expansion (~30 km yr?1) between 1996 and 2002, after which new detections slowed. Human movement of fish for aquaculture was identified as a primary cause of dispersal that interacted with flooding as an important secondary cause. The shortest paths across low elevation drainage divides between major basins revealed several potential corridors for future tilapia spread during flooding. Research into tilapia spatial metapopulation structure and economic fisheries status, more stringent regulation of aquaculture activities, pro-active fisheries management, and development of policies to screen potentially invasive species before importation are recommended to avoid additional releases of tilapia and further spread in the region.  相似文献   

16.
Evaluating and understanding biodiversity in marine ecosystems are both necessary and challenging for conservation. This paper compiles and summarizes current knowledge of the diversity of marine taxa in Canada''s three oceans while recognizing that this compilation is incomplete and will change in the future. That Canada has the longest coastline in the world and incorporates distinctly different biogeographic provinces and ecoregions (e.g., temperate through ice-covered areas) constrains this analysis. The taxonomic groups presented here include microbes, phytoplankton, macroalgae, zooplankton, benthic infauna, fishes, and marine mammals. The minimum number of species or taxa compiled here is 15,988 for the three Canadian oceans. However, this number clearly underestimates in several ways the total number of taxa present. First, there are significant gaps in the published literature. Second, the diversity of many habitats has not been compiled for all taxonomic groups (e.g., intertidal rocky shores, deep sea), and data compilations are based on short-term, directed research programs or longer-term monitoring activities with limited spatial resolution. Third, the biodiversity of large organisms is well known, but this is not true of smaller organisms. Finally, the greatest constraint on this summary is the willingness and capacity of those who collected the data to make it available to those interested in biodiversity meta-analyses. Confirmation of identities and intercomparison of studies are also constrained by the disturbing rate of decline in the number of taxonomists and systematists specializing on marine taxa in Canada. This decline is mostly the result of retirements of current specialists and to a lack of training and employment opportunities for new ones. Considering the difficulties encountered in compiling an overview of biogeographic data and the diversity of species or taxa in Canada''s three oceans, this synthesis is intended to serve as a biodiversity baseline for a new program on marine biodiversity, the Canadian Healthy Ocean Network. A major effort needs to be undertaken to establish a complete baseline of Canadian marine biodiversity of all taxonomic groups, especially if we are to understand and conserve this part of Canada''s natural heritage.  相似文献   

17.
Global climate change is increasingly considered one of the major threats to tropical coastal fisheries, potentially undermining important revenue and food security provided by coral reef ecosystems. While there has been significant and increasing work on understanding specific effects of climate change on coral reef fishes, few studies have considered large-bodied fisheries target species, limiting understanding of the effects of climate change on tropical fisheries. This review focuses on coral grouper (Plectropomus spp., and mainly Plectropomus leopardus), which are heavily fished throughout the Indian and Pacific oceans, and represent an exemplar group to assess potential effects of climate change on coral reef fisheries. In experimental studies, P. leopardus appear to be extremely sensitive to increasing ocean temperature, exhibiting declines in survivorship, aerobic scope and activity with relatively moderate increases in temperature. As such, ongoing ocean warming may jeopardize the catchability of coral grouper and sustainability of reef-based fisheries, especially at low latitudes. Notably, a significant portion of wild stocks of P. leopardus are already exposed to temperatures (≥30 °C) that have been shown to compromise individual performance and body condition. While there are considerable knowledge gaps in predicting effects of global climate change on coral grouper, such as their capacity to avoid, acclimate or adapt to changes in local environmental conditions, current information suggests that there is cause for concern. As such, we take the formative steps to outline both ecological and socioeconomic adaptations that could reduce vulnerability of coral reef fisheries to climate impacts on stocks of coral grouper, using a linked socio-economic framework.  相似文献   

18.
This study attempts to predict and verify possible spawning aggregation sites and times in the Los Roques Archipelago National Park, Venezuela, based on physical reef characteristics and the knowledge of experienced local fishermen. Three possible aggregation sites were selected for monitoring based on satellite images, low‐cost bathymetric mapping and interviews with experienced local fishermen. Abundances and sizes of 18 species that are known to form reproductive aggregations were monitored at these sites using underwater visual census for 7 days after each full moon from February to August, 2007. While spawning events were not observed, possible indirect evidence of spawning aggregations was found for Lutjanus analis at Cayo Sal and Boca de Sebastopol, Lutjanus apodus at Cayo Sal, Lutjanus cyanopterus at Cayo Sal and Piedra La Guasa and Epinephelus guttatus at Bajo California and Cayo de Agua. Additionally, indirect evidence was identified for the past existence of a spawning aggregation of Epinephelus striatus in the northern part of the archipelago, which may have been eliminated by overfishing c.15 years ago. Bathymetric mapping showed that the shelf edge at sites monitored in this study was shallower than at spawning aggregation sites in other parts of the Caribbean, and that sites were not proximal to deep water. While this study does not prove the existence or locations of spawning aggregations of reef fishes in the archipelago, it does add insight to a growing understanding of generalities in the relationship between seafloor characteristics and the locations of transient reef‐fish spawning aggregations in the Caribbean.  相似文献   

19.
The past decade has seen a considerable rise in international concern regarding the conservation status of sharks and rays. The demand for highly prized shark commodities continues to fuel the international trade and gives fisheries incentive to use these resources, which have a low intrinsic capability to recover. Recognising the urgency for regulation, many countries voted to include more shark and ray species in the Appendices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, the identification of fins in fisheries landings before they enter international trade is a major limitation for CITES compliance. This study reports the current performance of the iSharkFin system, a machine learning technology which aims to allow users to identify the species of a wet shark dorsal fin from its image. Photographs of 1147 wet dorsal fins from 39 shark species, collected in 12 countries, were used to train the algorithm over a four-year period. As new cohorts of images were used to test the performance of the learning algorithm, the accuracy of species assignments of known specimens was variable but did increase, reaching 85.3% and 59.1% at genus and species level respectively. The accuracy in predicting CITES-listed sharks versus unlisted sharks was 94.0% based on the 39 species currently represented in the baseline. Our results suggest that if supplied with high data inputs for specific fisheries assemblages and accompanied by user training, iSharkFin has promise for site-specific development as a rapid field identification tool in fisheries monitoring, and as a screening tool alongside traditional field morphology to detect potential CITES specimens for fisheries compliance and enforcement.  相似文献   

20.
Research trawling surveys and visual observations aboard manned underwater vehicles carried out at Whale Ridge revealed 116 species of bottom, near-bottom, over-bottom, and over-bottom-pelagic fish of 46 families. The data on the distribution, number, and behavior, along with some data on biology of the mass fish species, are given in the present paper. The following species prevail by number and biomass: splendid alfonsino Beryx splendens; boarfish Pseudopentaceros richardsoni; redbait Emmelichthys nitidus; flintperch Hoplostethus atlanticus; Helicolenus mouchezi; and fish of families Gempylidae, Oreosomatidae, Macrouridae, Moridae, Alepocephalidae, etc. All these species are subject to fisheries but the boarfish and alfonsino are most commercially important.  相似文献   

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