Further action on bycatch could boost United States fisheries performance

This paper examines the sustainability of United States fisheries managed under the Magnuson-Stevens Fishery Conservation and Management Act, the law that provides the framework for federal fisheries management. Sustainability across a broad suite of criteria, including health of the fished stock, bycatch, and effects on the habitat and ecosystem, was measured against the Monterey Bay Aquarium׳s Seafood Watch criteria for ecological sustainability. Seafood Watch ratings and numerical scores for U.S. federally managed fisheries were analyzed to elucidate strengths and weaknesses among federally-managed fisheries. Of U.S. federally managed fisheries assessed by Seafood Watch, only 2% are rated “Avoid”, and strong ratings for stock health for nearly all fisheries indicate that the Magnuson-Stevens Act is fundamentally succeeding at maintaining or rebuilding the abundance of targeted stocks. The majority (79%) of U.S. fisheries earn the intermediate rating of “Good Alternative”, and 19% earn the top rating of “Best Choice”. Given that U.S. fisheries management is considered among the strongest in the world, this analysis assesses why the majority of U.S. fisheries are not rated “Best Choice”. Fisheries for all variety of species, and using a wide range of fishing methods, can merit “Best Choice” status. However, the majority of U.S. fisheries do not achieve this rating due primarily to bycatch concerns. By improving performance with regard to bycatch, most “Good Alternative” U.S. federal fisheries could reach “Best Choice” status and reap rewards in the marketplace for that recognition. Findings suggest that current science-based management should be maintained in the Magnuson-Stevens Act reauthorization, managers should adopt best practices based on fisheries that are already performing well in the U.S., and more specific federal bycatch mitigation requirements should be implemented.     

Governance structures and sustainability in Indian Ocean sea cucumber fisheries

Good governance is paramount to the sustainability of fisheries, and inclusiveness of stakeholder groups has become the centerpiece in the ethos of managing small-scale fisheries. Understanding the effect of governance network structures on fishery sustainability can help guide governance to achieve desired outcomes. Data on resource users, fishing methods, governance networks and classifications of stock health were compiled for 17 sea cucumber fisheries in the Indian Ocean. The subjective influence of the actors and the complexity of governance networks on the health of wild stocks were analyzed. The fisheries differed widely in their resource users, fishing methods and governance networks. Little correspondence was found between the number of nodes in the governance networks and the health (exploitation status) of wild stocks. Government entities dominated the networks but neither their relative influence in the networks nor their proportionate contribution to the number of entities in the networks greatly affected stock health. These findings do not refute the benefits of inclusive governance, but rather suggest that multiple other factors (e.g. inadequate regulations, weak enforcement, high number of fishers) are also likely to play a role in influencing sea cucumber fishery sustainability. These factors must be tackled in tandem with good governance.     

Decomposing productivity and efficiency changes in the Alaska head and gut factory trawl fleet

Fishing fleets are subject to numerous factors that affect economic performance, making identification and attribution of such impacts difficult. This paper separately identifies the effects of changing input and output prices, fishery management, and quota allocations on total factor productivity using a Lowe Index. Indices account for technical change and decompose productivity estimates into its technical, environmental, and scale-mix components. This results in measures that reflect shifts in the production frontier, and movements by vessels toward and around the frontier, to capture economies of scale and mix after a policy shift to a catch share program that includes fishing cooperatives and a limited access fishery. The difference between cooperative and limited access vessels is exploited to compare the changes in economic performance between the groups after the introduction of the shift to catch shares and cooperative management, which allowed the vessels to improve the timing and coordination across multi-species fisheries and to decrease incidental catch of quota-limited bycatch species that had closed the target fisheries prematurely in the past. Results indicate that total factor productivity increased significantly after the move to a catch share program, largely due to increases in technical change that shifted out the production frontier of the fishery.     

Observations of Hector's dolphins (Cephalorhynchus hectori) associating with inshore fishing trawlers at Banks Peninsula,New Zealand

Fishing activities have the potential to alter the behaviour of cetaceans and pose a threat through bycatch. We present observations concerning the influence of inshore trawling on group size and behaviour of Hector's dolphins (Cephalorhynchus hectori) at Banks Peninsula, New Zealand, made during photo‐ID surveys from 2003 to 2007. Aggregations of dolphins, typically involved in what we assumed to be foraging behaviour, were observed following small inshore trawlers year‐round. Group size was larger for aggregations of dolphins following trawlers (mean ± SE = 22.9 ± 1.3, n = 83) than for non‐trawler groups (3.7 ± 0.2, n = 439), and dolphins were typically in a more “excited” state, frequently exhibiting aerial and sexual behaviours. We suggest that trawlers increase the availability of prey for Hector's dolphins and hence foraging behind trawlers is an energetically favourable activity. However, following trawlers probably also increases the risk of being caught in trawl nets, compounding the threats faced by this endangered species.     

Constraints and solutions for managing Pacific Island sea cucumber fisheries with an ecosystem approach

The ecosystem approach to fisheries (EAF) is a holistic paradigm that considers stocks of exploitable species, marine ecosystems and stakeholders. Management agencies must strike a balance between their capacity constraints and the requisites of management measures. Most small-scale sea cucumber fisheries of Pacific Islands have been plundered while others are being opened to commercial exploitation. Data from fishery managers and a regional workshop were used to assess the current problems, institutional constraints and solutions to the management of sea cucumber fisheries in 13 Pacific Island countries (PICs). Technical capacity was often strong for some management actions such as developing marine reserves but weak for others, such as enforcement. Using multi-disciplinary indicators, half of the fisheries were diagnosed by their managers as being overfished or depleted, despite evidence of optimistic bias. Fishery governance varied greatly among the PICs, and co-management frameworks were not typical of any cultural region. Management objectives were prioritised differently among managers but most highly ranked was to protect ecological resilience. The fishery managers proposed different sets of regulatory measures and various management actions, such as surveys to collect socio-economic and fishery-dependent data, support for local governance and strong enforcement – all widely under-practised. Pacific sea cucumber fisheries exemplify how the transition to an EAF by management institutions must involve reorganisation of their technical and human-resource capacities among management tasks. Levies on exports need to be internalised to fund improved management. Management agencies should consider a shift in resources from developing marine reserves, conducting underwater surveys and aquaculture-based restocking to strengthening enforcement capacity, stakeholder involvement and communication with fishers. In concert with these actions, short fishing seasons, shortlists of allowable species and tighter enforcement at export points may serve to turn the tide on boom-and-bust exploitation and safeguard biodiversity.     

Conflicting goals in fisheries management—A study of the Norwegian cod fisheries

A multi-objective programming model has been applied to investigate conflicting goals of the Norwegian cod fisheries. The goals included in this article are economic rent and employment. Fisheries managers are confronted with the problem of how best to allocate the total allowable catch (TAC) of cod among eight vessel groups. Compromise solutions taking into account both objectives by giving them equal weights in the multi-objective programming model are calculated and discussed. This article is an extension of an earlier article in which the trade-off analysis was performed using data only for North Norway and one particular year. The present analysis includes the entire Norwegian cod fisheries and is carried out using time series data for 2003–2007, examining the annual variations of key economic and technological parameters of the cod fisheries. Based on the results from compromise programming, the article discusses management and policy implications of reallocation of the TAC by vessel groups.     

基于BP模型的渔业资源可持续利用综合动态评价

在对传统可持续发展评价方法进行评述的基础上 ,利用神经网络具有自组织、自学习、自适应以及非线性等功能 ,提出了以BP模型为基础包括经济、社会和资源环境三个方面的渔业资源可持续利用综合动态评价方法 ,该方法克服了传统上单纯从生物方面进行资源评价的缺陷。并以东海区 1978～ 1990年的渔业资源可持续利用状况为例进行了实证分析 ,建立以BP模型为基础的东海区渔业资源可持续利用的综合动态评价模型。     

浙江近海海洋鱼类增殖放流现状分析

20世纪80年代以来,浙江近海的主要渔业资源呈现衰退趋势,因此从2000年至今相关单位持续开展人工增殖放流以修复渔业资源。文章基于2017—2021年浙江近海鱼类增殖放流统计数据作出分析,对比放流资金、放流数量、放流物种等变化趋势得出：2017—2021年主要在浙江近海12处重要的增殖放流海域投放了大黄鱼（Larimichthys crocea）、黑鲷（Acanthopagrus schlegelii）、黄姑鱼（Nibea albiflora）、条石鲷（Oplegnathus fasciatus）等16种海洋鱼类,累计投入放流资金11 285.9万元,投放海洋鱼类苗种共计46 799.8万尾,其中标志鱼投入共330.1万元,放流苗种48.8万尾。调查和文献报道显示,增殖放流对增加浙江近海海洋鱼类生物资源量、恢复海洋鱼类群落结构、保护海洋生物多样性,促进海洋渔业的发展等方面起到积极的作用。根据调研情况和相关文献梳理了增殖放流存在的问题并提出了相关的改进建议,以期为今后科学规范实施增殖放流提供参考。     

基于PSR模型的渔业用岛生态状况评价——以菜坨子岛为例

菜坨子岛位于大连市长海县,为无居民海岛,功能定位为渔业用岛。依据无居民海岛生态系统的特点和渔业用岛功能定位,文章使用压力-状态-响应模型设置3层指标体系,对菜坨子岛生态状况进行评价。指标评价方法采用专家评价法及单因子环境质量指数法、综合评价指数法等计算各级权重值和指标值。基于2015年现场调查数据,采用层次分析法对压力-状态-响应模型进行计算,得出菜坨子岛年生态状况分值及评价结果。结果表明,菜坨子岛总体状态为“优”（分值为0.811 1）。此外,经过对评价指标进一步优化后,可将该评价方法推广到对其他渔业用无居民海岛的生态状况评价,为其开发和保护提供依据。     

休闲渔业对渔业经济高质量发展的贡献度研究

为测度当前我国休闲渔业的发展规模,选取2013—2018年的休闲渔业产值和渔业经济产值为变量,构建了直接贡献率、间接贡献率和回归分析法建立的边际贡献率模型,测算了休闲渔业对渔业总产值的贡献度。结果表明,2014—2018年的直接贡献率分别为4.38%、4.95%、14.3%、6.58%和12.5%,2014—2018年的间接贡献率分别为0.317%、0.261%、0.752%、0.403%和0.533%,2013—2018年,休闲渔业对于渔业经济总值的边际贡献率为9.9%,由数据得出,当前我国休闲渔业规模还很小,发展水平也很低,整体实力也很薄弱。为此提出：加大休闲渔业的政策扶持力度;设计最为合理的休闲渔业项目;加大休闲渔业的宣传;加强休闲渔业与高校的合作,培养更多的休闲渔业方向的高精尖人才;推动休闲渔业从业者专业素养整体水平的提高;鼓励休闲渔业从业者之间的帮助;健全完善休闲渔业的监督管理体制;加强组织领导,促进休闲渔业发展。