Interdecadal variability of anchoveta abundance and overcapacity of the fishery in Peru

Paleontological and historical stock abundance estimates indicate that pelagic fish populations inhabiting upwelling ecosystems undergo large interdecadal variations in abundance with amplitudes equal to, if not larger than, the interannual variability. The interdecadal variability is characterized by periods of high and low abundance, termed “pseudo-cycles”, because of their irregular periodicity. Fisheries targeting small pelagic fish suffer from overall overcapitalization, like many other fisheries, but also from an additional overcapitalization problem: a phase displacement between rapid fish population decreases and a slower disinvestment which follows. This lag produces economic hardship.Here we document the fish:fishery relationship for the Peruvian anchoveta. Anchoveta pseudo-cycles of 20 to >100 years are observed, with the present stock abundance most likely located near upper part of the cycle. Fleet overcapacity expressed as the proportion of unused present capacity is estimated at 72% and processing overcapacity at 89%. A simple bio-economic model demonstrates the risks associated with the pseudo-periodicity in fish stock abundance in conjunction with fishery investment, open access, and overcapacity: a timing bomb for the fishing sector. The lag between disinvestment and decrease in fish abundance is quantified. A reduction of the fishing and processing capacity and measures to decrease the investment lag are recommended to limit the social, economical and political tensions that will result from the expected decrease in stock abundance. Finally, some management options to reduce these risks are discussed.     

Can vessel buybacks pay off: An evaluation of an industry funded fishing vessel buyback

Fishing vessel and permit buyback programs have been implemented to reduce excess capacity and improve profitability in a number of fisheries around the world. These programs are generally publicly funded, but in a few cases they have been financed by loans to be paid back by the remaining fleet. In 2003, a buyback permanently removed 91 vessels and 239 fishing permits from the Pacific groundfish trawl fishery and associated corollary fisheries of Dungeness crab and pink shrimp. The buyback was financed with $10 million in public funding and a $36 million loan to be repaid over 30 years with fees on landings. In the same year, a control date was set for catch share program in the groundfish trawl fishery. When the catch share program was implemented in 2011, the permit owners that remained in the fishery after the buyback were allocated the quota shares that would otherwise have been issued to the permits bought back in 2003. Estimates of the annual profits generated by this quota are compared to the cost of servicing the buyback loan. The results provide evidence that a buyback program, when implemented in conjunction with catch shares, can enable a sustained increase in profitability for the remaining vessels sufficient to justify its cost. However, using landings taxes as the mechanism to repay the loan may result in a mismatch between those who benefit from and pay for the buyback.     

Mechanization and technical interactions in multi-species Indian fisheries: implications for economic and biological sustainability

Joint capture of multiple species by multiple fleets results in technical and economic interactions between fleets. This paper develops a bioeconomic model that incorporates interrelationships between fleets for a representative fishery in India. The study analyzes the impacts of overcapitalization on bio-economic sustainability. Results show that a continuation of the current fishing intensity would deplete most commercially important species in the near future. However, an optimal effort re-allocation between fleets would increase fishery profits substantially, although some species would remain unsustainable. The study demonstrates how the newly emerging, large bodies of fishery data can be used for management decisions in developing countries.     

Distributional effects of property rights: Transitions in the Atlantic Herring fishery

A principal challenge in developing any fishery management plan is the allocation of benefits and costs among participants in the fishery. This process is further complicated by imperfect information about future market demand and limited ability to predict the consequences of regulatory change. This paper offers a new approach to policymakers, using econometric analysis to simulate the potential impact of individual tradable quotas (ITQs) in a fishery. We compare the distribution of harvest across participants in the Atlantic Herring fishery under the current open access regime and under a potential ITQ regime, assuming two different levels of future demand. Our results show that production efficiency varies by vessel gear, home-port and relationship with buyers. Some of the predicted consequences of ITQs are: vessels from Massachusetts will gain share relative to those from Maine; trawlers will gain share relative to purse seine vessels; and independent vessels will lose share relative to vessels that are primarily contracted to specific processors or bait companies. These results will help policymakers in developing future management plans for the herring fishery. More generally, this analytical approach can help regulators in any fishery assess the potential impact of alternative policy changes under alternative future demand scenarios.     

Measures of fishing fleet diversity in the New England groundfish fishery

After 16 years under a limited access program with effort controls, the New England groundfish fishery transitioned to a catch share management system in 2010. For much of its earlier management history, issues related to fishing capacity were paramount as effort controls were increasingly restrictive to meet biological objectives. As the size of the active fleet declined from over 1000 vessels from 1994 to 2001 to less than 400 vessels in 2012, the management concern shifted to fleet diversity. Fleet diversity has been cast in terms of vessels based on characteristics such as size, gear, and region rather than their share in landings or economic value. Measuring fleet diversity with indices commonly used in the biodiversity literature such as richness, effective diversity based on the Shannon index, and evenness appears appropriate for this context. In this paper these indices were applied to measure changes in diversity of the active New England groundfish fleet from 1996 to 2012. Fleet diversity as measured by the Shannon Index has declined by approximately 35% from 1996 to 2012, but has remained relatively stable since 2007. Forty vessel types were present in all 17 years, which accounted for about 85% of active groundfish vessels and over 90% of total groundfish landings in all years. Even though the fleet size and overall diversity have declined the “core” groundfish fleet remains stable.     

基于BiLSTM模型的远洋渔船类型识别研究

船舶自动识别系统(Automatic identification system,AIS)为渔业资源和渔船捕捞活动管理和研究提供了可能.明确船舶作业类型是开展AIS信息渔业研究应用前提,为渔业研究和管理提供渔船捕捞类型基础数据支撑,保障渔船作业安全和监督非法捕捞渔业活动,作者通过搜集整理3000多艘已知类型船舶信息,从...     

海洋牧场背景下的休闲渔业旅游发展模式研究

近年来随着产业融合的发展趋势显著,第一产业和第二产业开始向第三产业转型,海洋牧场建设发展过程中渔业与旅游业逐渐融合发展形成休闲渔业等渔业旅游形式。许多地区因地制宜形成了不同的休闲渔业发展模式,休闲渔业旅游发展多元化的趋势也在逐渐形成。文章对休闲渔业的概念进行了阐述,介绍了休闲渔业的产生与发展,并对我国休闲渔业的旅游模式进行归纳,提出当前休闲渔业发展存在的问题。如:发展观念滞后,缺乏长远规划;海洋休闲渔业产业结构单一;缺乏高素质的从业人员;科技、资金投入不足等。最后总结了海洋牧场背景下休闲渔业的未来发展趋势并对发展方向提出建议。     

海洋作业渔船管理系统的设计与运行试验

对渔政管理指挥系统建设项日中的业务软件部分渔船管理系统的设计方案进行了介绍。根据我国渔洋作业渔船的实际管理模式，提出了渔船管理系统设计方案。系统通过网络化的业务处理和管理流程，规范渔船建造、审批、登记以及捕捞许可证发放等管理业务，实现渔船控制指标的统一分配，以控制捕捞业发展规模和保护我国的渔业资源。系统以Microsoft VB6．0，Delphi6．0开发，在Window98／2000／XP环境下运行。通过运行试验，对系统运行环境进行了评估，为渔政管理信息化的建设、系统升级提供了经验和技术依据。     

Environmental assessment of frozen common octopus (Octopus vulgaris) captured by Spanish fishing vessels in the Mauritanian EEZ

Mauritania, one of the most dependent fish trade nations in the world, has an important octopus fishery within its EEZ. Fishing treaties between the EU and this Sub-Saharan nation have permitted 24 Spanish cephalopod trawling vessels to target this species for its export as a frozen product, mainly to Spain, Italy and Japan. This article presents Life Cycle Assessment (LCA) methodology in order to assess and compare the environmental impacts related to the capture, processing and exportation of packed frozen octopus from this fishery to the main importing nations. Environmental results show that frozen common octopus presented a remarkable dominance of the fishing vessel activities, due to the high energy intensity of the fishery and to the fact that these activities include harvesting, processing and preliminary packaging. Post-harvesting activities presented low relative contributions in all impact categories, minimizing the food mile effect of exporting to Japan, thanks to the slow transportation through marine freight of frozen octopus. The results for fishery-specific indicators showed regular trends for trawling fleets, with high discard and seafloor impact rates. Therefore, improvement actions focused on the minimization of energy use and fishery-specific impacts and the shift to less ozone layer damaging cooling agents are the main targets in order to improve the sustainability of this product, as long as the slow freighting characteristics of the imported product are maintained.     

Productivity change and fleet restructuring after transition to individual transferable quota management

Productivity change after transition to an individual transferable quota (ITQ) management system is driven by exit of some vessels, entry of other vessels, and changes in productivity of existing vessels. Generally, it is thought that an ITQ system boosts productivity due to the exit of less productive vessels. However, ITQ management systems also create an additional barrier to entry, and more productive vessels may not be able to enter the fishery. This study constructs the Färe–Primont index to measure productivity change for the Mid-Atlantic surf clam and ocean quahog fishery over a 32 year time period, which includes both pre and post-ITQ time periods. The index is then combined with a biomass change index to arrive at a measure of biomass adjusted productivity change. Results show that when biomass changes are considered, positive productivity gains occurred throughout the time period. Further examination of contributions from entering and survivor vessels show that entering vessels had little impact on aggregate productivity, but on an individual basis, they eventually were equal in productivity to survivor vessels.     

基于船位监控系统的拖网捕捞努力量提取方法研究

为了基于船位监控系统提取拖网捕捞努力量,通过统计航速获得3个峰值,拖网作业在第2个峰值,即1~2.1 m/s,拖网作业航向差一般在–50°~50°。利用航速、航向差阈值设定,把拖网船状态划分为慢速、作业、航行,然后提取出捕捞作业状态点,1 423艘拖网船共提取到处于捕捞状态的点318 433个,合计拖网捕捞时间15 921 h,利用反距离加权插值法生成捕捞强度分布变化趋势图。捕捞努力量在渔业资源研究中是重要的参考值之一,与传统的捕捞努力量计算方法相比,该方法具有实时、大范围、快速、分辨率高的特点,能够用于辅助渔业资源保护。     

Catch shares have not led to catch-quota balancing in two North American multispecies trawl fisheries

Catch shares, where annual catch limits are divided among individuals, communities or cooperatives, are a commonly used fisheries management strategy to increase profits and reduce overcapitalization. Usually these quota shares can be sold or leased, which is theorized to allow for greater utilization of fleet-wide quota. However, this catch-quota balancing may not be achieved in multispecies trawl fisheries where it is difficult to selectively target valuable species while avoiding overfished species. Two similar catch-share-managed, multispecies trawl fisheries were compared to evaluate whether catch shares lead to catch-quota balancing. The U.S. West Coast Groundfish fishery has several species with low total allowable catches (TACs) while the Canadian British Columbia Trawl fishery has comparatively higher TACs. Results indicate that the West Coast fishery had a statistically significant decrease in catch-quota ratios from 0.41 in the three years before catch shares to 0.29 in the three years after catch shares. In contrast, the BC fishery experience no statistically significant change in fishery-wide average catch-quota ratios, which were 0.70 in the three years before and 0.62 in the three years after catch shares. In the West Coast fishery, the risk of exceeding quotas for some species may be so high that fishers are unable to achieve high degrees of catch-quota balancing and instead focus on species that can be easily selected with changes in fishing behavior. Multispecies fisheries management has direct tradeoffs between maximizing yield and achieving conservation goals, and these results may highlight the tradeoff between rebuilding overfished species by reducing TACs, and the achievement of catch-quota balancing.     

Unravelling the dynamics of a multi-gear fleet – Inputs for fisheries assessment and management under the Common Fisheries Policy

Effective species management requires good knowledge on vessel dynamics, either at a stock basis or through the establishment of multiannual management plans as advisable under the new European Common Fisheries Policy (CFP). Achieving such knowledge on Portuguese multi-gear fisheries is challenging given the large number of species caught and the different management measures applied to potential target species. The latter ranges from no input or output controls to output controls based on individual vessel quotas (IVQ). To provide accurate regional knowledge to the CFP, the dynamics of vessels involved in the trammel net fishery targeting anglerfish (Lophius spp.) was characterised based on onboard sampling data and logbook reports. The selected vessels were very dynamic, and were found to target other species such as hake (Merluccius merluccius), John Dory (Zeus faber) and octopus (Octopus vulgaris). Anglerfish landing trends can be explained by changes in abundance, quota availability and shifts/changes in fishing effort. Overall, the dynamics of these vessels varied with area of exploitation, IVQ value and anglerfish total allowable catch (TAC). These results show the influence of different management systems in the dynamics of vessels and the advantage of an IVQ management system, where fishers can spatially and temporally allocate effort. Results also highlight a fishing effort shift towards unregulated species in face of IVQ or TAC restrictions.     

The structure and evolution of the coastal migrant fishery of Kenya

The current study was carried out over a period of one year to characterise the coastal migrant fishery of Kenya. The study looked at gears and vessels used, and ownership, demographic factors including ages of the fishers and family sizes, migrant activity and resource conservation at two main fishing villages in Kenya; Vanga and Mayungu in the south and north coasts, straddling at 4.663°S and 39.215°E and 3.214°S and 40.135°E respectively. Further, the fishers were categorised with regard to fishing, gear and vessel operation and trade, and evolution upon entry into the fishery was also assessed in order to define fisher-stake in the fishery for resource management and conservation planning. Structured questionnaires were used to interview the fishers, and data and information recorded from 1018 fishers during the survey. Migrants accounted for over 63% of the fishers in the two study sites, with majority of the fishers lying in the 15–45 year age bracket. Dependence level averages at 4–6 person families per fisher. Entry to the fishery was mainly at seamen level, progressing to fishermen and finally to fish dealers (tajiris), with the latter holding >62% capital in the fishery. Resource management in the fishery was low and only 10% of the fishers were active participants in marine conservation and community beach management issues. Fisher migrations were mainly monsoon season-linked (>58%) although social factors such as family location determined to a great extent the expanse of the migrations. The revival of fisheries cooperatives and active participation in community resource management and conservation groups is envisaged as the key to the sustainability of both the marine resources and the economies associated with this high mobility, cross-border fishery.     

The profitability of the Spanish swordfish fleet in the North Atlantic

Our aim is to analyse the profitability of the Spanish swordfish fleet in the North Atlantic on the basis of the estimate of the gross profit per standard vessel, the average yield and the investment payback period (PP). The swordfish fleet has grown over the last decade to become the main producer in this fishery and one of the most stable fleets of all the Spanish fisheries. The results obtained show increases in profit per vessel, although there was a slight decrease in the final year studied, relatively high rates of return and PP shorter than the average life of one of the fleet's standard vessels.     

The introduction of limited entry: The New Zealand rock lobster fishery

The author describes the implementation of a controlled or limited entry fishery for New Zealand rock lobsters. The background to the implementation of limited entry is described and the decrease in annual landings per vessel in the period 1955–1977 is pointed out. The New Zealand licensing system is outlined, attention being paid to continuous and seasonal licences, allocation of licences, controlled fishing areas, and fishing methods and gear restrictions. The number of rock lobster vessels decreased from 1574 in 1979 to 970 after the initial round of licensing.     

基于深度学习和时空特征融合的海洋渔船密度预测方法

为了从海量渔船轨迹数据中挖掘隐含的信息和知识,进而为渔业行政主管部门的决策提供科学依据,本研究以AIS渔船轨迹数据为研究对象,提出了一种基于深度学习和面向时空特征融合的海洋渔船密度预测方法：首先,利用渔船轨迹数据集对渔船行驶区域进行网格划分;其次,筛选出渔船高密度区域进行研究,避免数据稀疏性问题;再次,根据渔船轨迹数据的时空分析,构建三维时空融合矩阵;最后,通过卷积循环神经网络模型捕获渔船分布的时间和空间特征,并利用卷积神经网络的堆叠加强对空间特征的学习。实验通过东海海域渔船真实轨迹数据进行具体测试,结果表明渔船密度预测值与真实值非常接近,平均绝对误差为4×10-4,模型较好地拟合了渔船密度分布特征,有效地提高了渔船捕捞热点预测的准确性和鲁棒性。     

Impacts on CPUE from vessel fleet composition changes in an Australian lobster (Jasus edwardsii) fishery

The Australian Victorian Western Zone rock lobster fishery is assessed using standardised catch-per-unit-effort (CPUE). Nominal CPUE declined over 1978–2009, but this underrepresents the estimated decline in abundance, and since 2009 standardised CPUE rose notably less than nominal CPUE. This study identified vessel as a key factor that explains the discrepancy between nominal and standardised CPUE. The composition of the fleet changed since 2009, under the pressure of constraining total allowable catch quotas, with vessels exiting the fishery having substantially lower estimated catchability, which increased the average catchability of the remaining fleet. New diagnostic indices were constructed to quantify discrepancies between trends in nominal and standardised CPUE that assisted in identifying periods during which both catchability and fleet composition changed.     

Managing Jamaica's queen conch resources

Jamaica's industrial fishery for queen conch (Strombus gigas) has produced a substantial amount of much-needed foreign exchange and for at least 10 years has been the most valuable component of all commercial marine fisheries activities. Since its inception in 1990 it has grown tremendously and may now be at some risk of collapse, due to problems including, among other factors, overfishing, poor enforcement, foreign poaching and under-reporting of catches. This paper examines and analyzes the problems relating to management of the conch fishery and speculates on its future. The main problems are overfishing by licensed fishers who take more than permitted, and serious poaching by industrial vessels mainly from Honduras, which exploit poor high seas enforcement by Jamaican authorities. For nearly two years the official fishery was closed due to legal issues. During closures, considerable foreign poaching occurred. The paper suggests that increased roles for the coast guard, continued quota reductions, and the Convention on International Trade in Endangered Species of Flora and Fauna (CITES), could be the best options for sustainability.     

Eco-labeling of seafood: Does it affect the harvesting patterns of Norwegian fishermen?

The aim of this paper is to compare the criteria for eco-labeling of wild-caught fish in the Norwegian eco-certified fisheries, and to study if these eco-labels affect the harvesting patterns of Norwegian fishermen. The eco-labels Marine Stewardship Council (MSC), KRAV and Friend of the Sea (FOS) as applied in 2009 were studied. In this study, the harvesting patterns are defined by using the following parameters: season, catch area, size of fishing vessel, gear type, bycatch, location of landing site and distance to the fishing ground. KRAV had more specific criteria than did MSC and FOS in specific fisheries regarding time of the fishing effort, catch area, size of fishing vessels, gear type (e.g. hook size, and the use of beam trawlers was not permitted) and distance to the fishing ground. The findings show that few of the eco-label requirements influenced these aspects in Norwegian fisheries.