Relationships between catch and effort in Fijian multispecies reef fisheries subject to different levels of exploitation

Abstract The catch-per-unit-effort (CPUE) and value-of-catch-per-unit-effort (VPUE) of reef-associated fish species from six Fijian native fishing grounds ( qoliqoli ) subject to different fishing intensities were determined using records of fishing activity from a voluntary logbook scheme. Line and spear fishing techniques were used for more than half the total fishing time (h person^-1 d^-1) in all qoliqoli , and yet the favoured technique in a given qoliqoli was frequently less efficient (lower CPUE) than other techniques. The popularity of relatively ineffective fishing methods implies that fishermen did not always attempt to maximize their catch rates. To compare fishing effort in different qoliqoli , all effort was rescaled on the basis of its recorded efficiency (measured as multispecies CPUE) and expressed as hours equivalent to boat-based spear fishing over coral by day to catch fish for sale. Total fishing intensity in the six qoliqoli ranged from 72 to 4310 h km^-2 reef year^-1. The relationship between catch and effort was linear at all fishing intensities, suggesting that the qoliqoli were all fished on a sustainable basis. Furthermore, whilst there was a significant difference in CPUE and VPUE between the one or two qoliqoli with lowest fishing intensity and all the others, there were no significant differences between these other qoliqoli in terms of the VPUE of the saleable multispecies boat catch or the CPUE of species from piscivorous and carnivorous genera ( Epinephelus, Lethrinus and Plectropomus ) which the fishermen prefer to catch.     

南海“长笼”渔具调查分析

2004年7月中旬至8月底,笔者主要对海南省、广东省和广西壮族自治区沿海的渔具种类及其分布情况进行补充调查.调查采用现场测定、咨询和访问当地渔民与现场观摩相结合的方法,对每种渔具的渔具结构、作业渔船、作业方法、渔具历史和技术改进等内容进行调查研究[1-2].     

Dynamics of fishing gear allocation by fishers in small-scale coastal fisheries of Pelabuhanratu Bay, Indonesia

Abstract  Fishing gear usage in small-scale coastal fisheries of Pelabuhanratu Bay, Indonesia was explained by two approaches: temporal fishing gear allocation analysis and adaptive responses of fishers to external factors, especially climate and abundance of target species. Gear usage, with the exception of hand lines and seine nets, was more intensive during the dry season than the rainy season. The decision to use seine nets was governed by seasonal variability in the abundance of Auxis thazard , Lacepède, and Trichiurus spp. to the catch. Sustainable management of fishing activities in Pelabuhanratu Bay requires proportional reductions in the use of lift nets and fixed gillnets across the seasons rather than gear specific effort reductions.     

A preliminary appraisal of the contribution of recreational fishing to the fisheries sector in north-west Trinidad

Abstract An assessment of the recreational fishery in north-west Trinidad was made by questioning participants about the principal fishing methods used, location of activities, catches, effort and cost of fishing. Surface handline methods (live baiting [à la vive] and trolling) and rod and line (banking) were the most common methods used and were pursued mainly in the summer months (April to August). Total fish landings from the fishery were estimated at 1000 t year^-1, equivalent to about 10% of commercial catches for Trinidad. The principal species caught were kingfish, Scomberomorus cavalla (Cuv.), carite, Scomberomorus brasiliensis (Cuv.), cavalli, Caranx hippos (L.), snappers, Lutjanus spp., and groupers, Epinephelus spp. Many of the fishermen sold their catch to offset the costs of the fishing trip and thus competed with commercial fishermen. Recommendations for monitoring and possibly regulating the fishery through a licensing scheme are made.     

对我国渔具分类标准的探讨

随着渔业科学技术日益发展、学术交流日益频繁以及全国渔具准入标准制订和实施工作不断推进,我国现有的渔具分类国家标准《渔具分类、命名及代号》(GB/T 5147-2003)在对渔具的具体分类上存在的一些问题也逐渐显现。本文通过对比我国渔具分类国家标准和FAO渔具统计分类国际标准(ISSCFG),分析了两个标准在渔具分类的定位、具体分类等方面的区别和联系,并结合笔者在教学和科研实践活动中所遇到的国家标准在"类"、"型"和"式"方面可能存在欠缺完整性、灵活性、适应性、区分缺乏统一依据等问题,提出了对我国现有渔具分类国家标准进行修订等建议,以期加快对现有国家标准的复审和修订,维护国家标准的权威性,并使各项渔业管理工作具有统一的标准。     

珠海“蟹夹”渔具的调查分析

根据“蟹夹”的渔具结构和捕捞原理,将其定名为漂流延绳弹夹笼壶。介绍了“蟹夹”的捕捞对象和作业方式,对其渔具性能进行了分析,对“蟹夹”渔具管理提出了若干意见。     

Optimising codend configuration in a multispecies demersal trawl fishery

Abstract The relative efficiencies and selectivities of conventional and modified codends were examined in a demersal trawl fishery targeting several species, including eastern king prawns, Penaeus plebejus (Hess), whiting, Sillago spp. and cephalopods. The modifications to codends included: (i) reducing the circumference; (ii) increasing the mesh size in conventional diamond‐mesh designs; and (iii) orientating meshes on the bar so that they were square shaped. The codends were tested against a fine‐meshed control in paired comparisons onboard three commercial trawlers. The conventional codend comprised 41‐mm diamond‐shaped mesh attached to an anterior extension section at a ratio of 150 to 100 meshes and was demonstrated to be non‐selective for the targeted species. Reducing codend circumference to 100 meshes and increasing the size of mesh to 45 mm both improved selection for eastern king prawns, but the lateral mesh openings were estimated to be insufficient to allow juveniles of the other key species to escape. By contrast, codends made from 35‐ and 41‐mm mesh hung on the bar improved the size selection for eastern king prawns and selected stout whiting, Sillago robusta (Stead) (the smallest commercial‐sized fish) across narrow selection ranges and at 50% sizes of retention (L₅₀s) that were closely correlated to the transverse morphology of fish and the maximum mesh opening. With the exception of a reduction in catches of octopus, Octopus spp., by the 41‐square codend, there were no other impacts on commercial catches by the square‐mesh designs. It was concluded that diamond‐mesh codends are inappropriate for use throughout this multispecies fishery and that a modified design comprising at least 35‐mm mesh hung on the bar is required to minimise the fishing mortality of unwanted sizes of the key target species. The results are discussed in terms of the utility of these types of modifications for closely regulating selection in penaeid‐shrimp trawls.     

日本资源管理型渔业体系下的典型作业方式管制实践

通过文献研究,对日本资源管理型渔业体系下的典型作业方式管理措施进行梳理,以期对我国典型作业方式准入制度的构建和完善提供参考。对围网、底拖网、刺网和流网、定置网及鱿钓等5种日本渔业主要作业方式的管理措施体系进行了分类和介绍,认为日本的渔业管理通过不同层级的权限许可,根据海洋渔业资源的自然属性差异采取区域化的管理模式,并以恢复渔业资源为目标,逐步推进从总可捕量管理制度向捕捞努力量控制制度的转变。     

Estimates of fishing gear loss rates at a global scale: A literature review and meta‐analysis

Abandoned, lost or otherwise discarded fishing gear (ALDFG) represents a significant, yet ultimately unknown amount of global marine debris, with serious environmental and socioeconomic impacts. This study reviews 68 publications from 1975 to 2017 that contain quantitative information about fishing gear losses. Gear loss estimates reported by the studies ranged widely, with all net studies reviewed reporting annual gear loss rates from 0% to 79.8%, all trap studies reporting gear loss rates from 0% to 88%, and all line studies reporting gear loss rates from 0.1% to 79.2%. Information obtained from this review was used to perform a meta‐analysis that provides the first synthetic, statistically robust estimates of global fishing gear losses. The meta‐analysis estimates global fishing gear losses for different major gear types. We estimate that 5.7% of all fishing nets, 8.6% of all traps, and 29% of all lines are lost around the world each year. Furthermore, we identified key gear characteristics, operational aspects and environmental contexts that influence gear loss. These estimates can be used to support sustainable fisheries development through informing risk assessments for fisheries and monitoring and assessment efforts to reduce gear losses.     

Beyond Individual Transferrable Quotas: methodologies for integrating ecosystem impacts of fishing into fisheries catch rights

While there has been a growing concern for the adverse ecological impacts of fishing, progress on incorporating these into operational fisheries management has been slow. Many fisheries management organizations have addressed the problem of overharvesting and over‐capitalization first. In this domain, the question of access regulation has gained growing recognition as a key dimension of fisheries sustainability, leading to recommendation and progressive implementation of rights‐based systems, in particular Individual Transferrable Quotas (ITQs). While adjustments in fishing capacity resulting from the implementation of these systems may entail a reduction in some unwanted ecosystem impacts of fishing, it is also recognized that they will not be sufficient to achieve the ecological outcomes increasingly demanded by the global community. There is thus a need to examine the possibilities for a common management framework for dealing with both over‐capitalization of fisheries and adverse ecological effects of fishing. In this paper, we examine the feasibility of incorporating greater ecosystem goods and services into ITQ policy instruments initially designed with a narrow focus on commercial target species. We consider the advantages and limitations of alternative approaches in this respect and identify some of the practical issues associated with the different alternatives, in particular the underpinning knowledge requirements. We argue that given the need for increasingly streamlined management processes, further investigation into practical ways forward in this domain is crucial if management of fisheries is to achieve economic efficiency while fully encompassing the ecologically sustainable development objectives of ecosystem‐based fisheries management.     

Health in fishing communities: A global perspective

In resource‐dependent communities such as fishing communities, human health underpins the ability of individuals and families to maintain viable livelihoods. Fishing is a dangerous occupation, in which fishers are exposed to health risks both on and offshore. Many of these risks and associated health concerns also extend to fishing families and wider communities. Despite the importance of health, there is a lack of understanding of the breadth of health issues affecting people associated with fishing. This study presents the findings of a scoping review of peer‐reviewed literature that identifies the range of health issues and health determinants studied in fishing communities around the world. The findings reveal a wide variety of documented health issues, but with greater emphasis on physical health and occupational and behavioral factors, with limited attention paid to mental health. The majority of studies focused on fishers themselves, as opposed to other subgroups within fishing communities. Geographic differences in the health topics investigated highlight prevalent concerns and offer potential to share insights and solutions across contexts. The breadth of findings illustrates the complexity of health for people dependent on fishing, and the relevance of the many health determinants in maintaining viable fishing communities. We propose that a social well‐being approach offers an integrative lens through which a better understanding of human health in fisheries can be achieved and used to inform fisheries management that is ecologically and socially sustainable.     

对印度尼西亚海域中国渔船使用拖网渔具的分析和探讨

本文探讨了中国渔船在印度尼西亚海域使用的拖网渔具,从渔具使用规格、缩结状态和结构等方面进行了分析,指出这类渔具在浅水渔场捕捞带鱼时有良好适应性,但局部配纲不当,网具贴底程度未达到最佳状态。由于网目大,有些局部改革可能导致敏感的负面反应。作者认为,这类网具今后的改革应着眼于提高拖速,以增加对某些优质鱼的兼捕比例。     

Fishing operations and adaptive strategies of small‐scale fishers: insights for fisheries management in data‐poor situations

Small‐scale fisheries' management is complex given its multigear, multispecies nature; despite this, fishing effort has usually been controlled by nominal units, ignoring changes in effective fishing effort. This study aimed to understand the adaptive strategies of small‐scale fishers in San Felipe, Yucatan, Mexico through an analysis of their fishing operations. Minor changes in trip numbers among three seasons were observed, but increases in fishing time, depth and travel costs from one season to another at the operational level were found. It was also evident that high value species at the beginning of the season were gradually replaced by low‐value finfish as the season progresses. The results provide insights for new adaptive management strategies according to fisher's adaptive responses. For instance, using boats or fishing trips as fishing effort units in Yucatan may not be the most appropriated unit for management, as fishers adapt their strategies at different levels.     

构建我国海洋捕捞权制度的分析

《物权法》第123条对捕捞权的规定,将促进我国海洋渔业管理的改革,建立海洋捕捞权制度。海洋捕捞权制度,是一种以权利为中心的渔业管理制度,实现渔业资源的可持续利用是其首要目标。根据《物权法》的规定,海洋捕捞权,应限于国家所属的海域,即领海与内水。捕捞权的分配应优先考虑沿海捕捞主体。根据现行海洋渔业管理制度,可能有三种构建海洋捕捞权制度的途径,即以捕捞许可证为载体、以马力指标为载体和以捕捞限额为载体。结合国际渔业管理发展趋势以及我国政府改革与社区建设发展状况,文章认为,选择马力指标为载体构建海洋捕捞权制度,有利于实现其管理目标,避免社会公平问题,促进我国渔业管理由目前的投入控制管理制度向产出控制管理制度过渡,提高我国海洋渔业管理效果。     

基于灰色预测模型的我国海洋渔业发展趋势分析

综合应用船舶、机械、信息、新材料等技术,从海洋中捕捞经济渔获物并综合利用,是现代海洋捕捞业的主要特征。海洋捕捞技术的发展和创新,对保障我国食物安全、保护近海生态与资源、实现渔民增收和新渔村建设、推动渔业产业结构调整和转型、维护我国海洋权益等方面具有非常重要的作用。本文通过简析海洋捕捞渔场探测、渔具渔法与高效自动化辅渔助渔技术等方面的研究进展,提出海洋捕捞技术的重点发展方向,以期为我国海洋捕捞实现节能高效、生态友好和资源可持续利用,海洋捕捞技术升级和产业高质量发展提供参考。

     

Plastic gear loss estimates from remote observation of industrial fishing activity

Derelict fishing gear is a highly visible source of marine plastic pollution, causing mortality and ecosystem degradation with uncertain long-term consequences. The quantity of derelict gear entering the oceans remains unknown because of heterogeneity in fishing gear and effort, as well as inadequate monitoring. Prior studies have been limited in scope to specific fisheries and regions, and large-scale estimates lack an empirical basis. It is critically important for decision makers to have credible information in order to design effective remediation efforts. We estimated the amount of industrial fishing effort and the associated plastic debris entering the ocean globally each year from lost fishing gear. Using remote observations of fishing vessel activity paired with technical fishing gear models, we generated a bounding estimate for gear operation and loss worldwide in 2018. We estimate that industrial trawl, purse-seine and pelagic longline fisheries operated 2.1 Mt of plastic gear over 2018 to obtain 49.7 Mt of retained and discarded catch, representing 74% of industrial marine capture globally. The median estimate for plastic gear lost during the use of these gear types was 48.4 kt (95% confidence interval: 28.4–99.5 kt). This estimate excludes abandoned and discarded gear. Improved observation, especially of small-scale fisheries, is needed to better understand the sources of derelict gear. These findings serve as a benchmark for future monitoring and management efforts to reduce derelict gear in the global ocean.     

The hidden value of artisanal fisheries in Honduras

Declining fisheries catches are a global trend, with management failing to keep pace with growth in fishing effort and technological advances. The economic value of Honduras’ catches was estimated within the industrial and artisanal sectors. Catches were found to be 2.9 times greater than the official statistics between 1950 and 2015. The merging of industrial and artisanal catch data masked the decline in industrial catches and hid the strong growth of artisanal fisheries. In 1996, annual artisanal fisheries landed catches surpassed the industrial fishery sector, and in 2000, the annual net value of artisanal fisheries eclipsed the value of the industrial fisheries. These data highlight the importance of artisanal fisheries in Honduras and challenge the long‐held belief that the industrial sector contributes more to the national economy. The global paucity of fisheries data highlights the need for comprehensive strategies to collect more detailed and accurate fisheries data.     

福建底拖网捕捞能力的分析

根据2002年福建闽南地区双船底拖网和单船底拖网的生产调查及全省渔业统计，结合相关的渔捞记录，应用DEA法，分析了福建各地，市底拖网的捕捞能力和闽南地区不同作业方式捕捞能力及其影响因素，并与单位捕捞努力量渔获量计算进行比较。结果表明：福建各地、市实际拥有底拖网的渔船数量、功率和吨位可能达到的最大产出量的“能力利用度”差异悬殊，1999年和2001年最低的仅为19．4％、19．9％；全省底拖网平均“能力利用度”偏低，1999年和2001年分别为64．3％、67．5％，全省底拖网作业仍然存在渔船的投人数量过多、功率和吨位偏大的问题；因捕捞方式不同，影响捕捞能力的因子有所不同，但投入功率和作业天数都是影响双船底拖网和单船底拖网捕捞能力的主要因素；在考虑将单位捕捞努力量渔获量数据转换为“能力利用度”时，其前提条件是计算采用的因子必须一致。但单位捕捞努力量渔获量在考虑计算投入因子的数量上有很大的局限性，采用DEA法可获得各种投入要素下捕捞能力变化的信息，结果比较符合客观实际。     

Evolutionary impact assessment: accounting for evolutionary consequences of fishing in an ecosystem approach to fisheries management

Managing fisheries resources to maintain healthy ecosystems is one of the main goals of the ecosystem approach to fisheries (EAF). While a number of international treaties call for the implementation of EAF, there are still gaps in the underlying methodology. One aspect that has received substantial scientific attention recently is fisheries‐induced evolution (FIE). Increasing evidence indicates that intensive fishing has the potential to exert strong directional selection on life‐history traits, behaviour, physiology, and morphology of exploited fish. Of particular concern is that reversing evolutionary responses to fishing can be much more difficult than reversing demographic or phenotypically plastic responses. Furthermore, like climate change, multiple agents cause FIE, with effects accumulating over time. Consequently, FIE may alter the utility derived from fish stocks, which in turn can modify the monetary value living aquatic resources provide to society. Quantifying and predicting the evolutionary effects of fishing is therefore important for both ecological and economic reasons. An important reason this is not happening is the lack of an appropriate assessment framework. We therefore describe the evolutionary impact assessment (EvoIA) as a structured approach for assessing the evolutionary consequences of fishing and evaluating the predicted evolutionary outcomes of alternative management options. EvoIA can contribute to EAF by clarifying how evolution may alter stock properties and ecological relations, support the precautionary approach to fisheries management by addressing a previously overlooked source of uncertainty and risk, and thus contribute to sustainable fisheries.     

Artisanal fisheries in urban reservoirs: a case study from Brazil (Billings Reservoir, São Paulo Metropolitan Region)

Billings Reservoir is an urban reservoir located in the São Paulo Metropolitan Region. It supports 101 active artisanal fishermen. To describe this fishery, landings were recorded daily between February 1996 and January 1997 at Colônia (23° 50' 57' S; 46° 40' 02' W). In every landing, a data collector recorded catch, effort, fishing gears and fishing grounds. A total of 147 593 kg of fish were recorded in 3515 fishing trips. The exotic Nile tilapia, Oreochromis niloticus (L.), was the main species exploited (81.4% of the annual catches). Five other species were also targeted: the characid Astyanax eigenmaniorum (Cope) (13.0% of the annual catches); the erythrinid Hoplias aff . malabaricus (Block) (2.1%); the exotic cyprinid Cyprinus carpio L. (Campos & Fernández-Yépez) (2.4%); the curimatid Cyphocharax modestus L. (1.1%); and the pimelodid Rhamdia sp. (0.1%). Two main groups of fishermen were discriminated using Principal Components Analysis; these were associated with the type of fishing gear and fishing strategies, i.e. those who exploited Nile tilapia with cast nets and beating gill nets, and those who exploited other species with set gill nets. Management and maintenance of this fishery should consider the positive top-down effects that Nile tilapia could have in controlling eutrophication and also the social benefits.