基于文献计量学的中国—欧盟渔业科技合作现状与趋势分析

采用文献计量学方法,在Web of Science数据库中以Fishery、Fisheries、Aquaculture检索2003-2012年间的涉渔SCI文献,再使用数据分析工具Thomson Data Analyzer(TDA)软件,对检索结果的各个关键字段进行分析处理,对欧盟国家渔业科研现状、欧盟国家渔业科研合作现状和中国-欧盟渔业科技合作现状进行了研究。结果表明:中国与西班牙的渔业科研合作最为紧密,欧盟国家之间的合作比欧盟国家与中国合作得更为紧密,中国与欧盟国家的渔业科技合作仍有极大的提升空间;中欧渔业科研正向着多元化、紧密化、频繁化的趋势发展。     

Ecosystem modelling in the southern Benguela: comparisons of Atlantis,Ecopath with Ecosim,and OSMOSE under fishing scenarios

Ecosystem-based management of marine fisheries requires the use of simulation modelling to investigate the system-level impact of candidate fisheries management strategies. However, testing of fundamental assumptions such as system structure or process formulations is rarely done. In this study, we compare the output of three different ecosystem models (Atlantis, Ecopath with Ecosim, and OSMOSE) applied to the same ecosystem (the southern Benguela), to explore which ecosystem effects of fishing are most sensitive to model uncertainty. We subjected the models to two contrasting fishing pressure scenarios, applying high fishing pressure to either small pelagic fish or to adult hake. We compared the resulting model behaviour at a system level, and also at the level of model groups. We analysed the outputs in terms of various commonly used ecosystem indicators, and found some similarities in the overall behaviour of the models, despite major differences in model formulation and assumptions. Direction of change in system-level indicators was consistent for all models under the hake pressure scenario, although discrepancies emerged under the small-pelagic-fish scenario. Studying biomass response of individual model groups was key to understanding more integrated system-level metrics. All three models are based on existing knowledge of the system, and the convergence of model results increases confidence in the robustness of the model outputs. Points of divergence in the model results suggest important areas of future study. The use of feeding guilds to provide indicators for fish species at an aggregated level was explored, and proved to be an interesting alternative to aggregation by trophic level.     

基于Schaefer模型的东南太平洋茎柔鱼资源评估和管理

东南太平洋茎柔鱼(Dosidicus gigas)是世界范围内最重要的经济头足类之一,也是我国鱿钓渔船的重要捕捞对象。本文根据2003—2012年中国大陆的渔业数据和FAO统计的东南太平洋茎柔鱼产量数据,利用Schaefer模型,基于贝叶斯统计方法,分基准方案和敏感性分析方案对东南太平洋茎柔鱼资源进行评估,并对其管理策略做了风险分析。结果表明,年渔获量和CPUE数据为贝叶斯资源评估模型提供了足够多的信息。2003—2012年捕捞死亡率低于目标参考点F0.1,渔获量小于最大可持续产量,资源量大于目标参考点Bmsy,资源状况良好,未遭受过度捕捞。在基准方案下,最大可持续产量为142.9万吨,维持最大可持续产量的资源量为214.7万吨,此时的捕捞死亡率为0.682;在敏感性分析方案下,最大的可持续产量为152.5万吨,维持最大可持续产量的资源量为229.6万吨,此时的捕捞死亡率为0.691。决策分析和风险分析表明,当捕获率设定为0.3以下时,资源能够得到较好的养护,资源崩溃的可能性很低。将捕获率设定在0.3左右是最适的管理策略,此时的持续产量为99万吨左右。     

Harvesters׳ perspectives on the management of British Columbia׳s giant red sea cucumber fishery

In recent decades, sea cucumber fisheries have rapidly expanded worldwide to meet rising demand in Asian markets. Catch trends have often followed a boom-and-bust trajectory and skyrocketing sea cucumber value has often spurred fishery development that outpaced adequate biological research for informed stock assessment. Currently, the dive fishery for Giant red sea cucumber (Parastichopus californicus) in British Columbia, Canada is considered moderately exploited. However, basic population parameters such as recruitment and mortality rates are still largely unknown, creating important sources of uncertainty in the fishery׳s stock assessment model. This study presents the results of an interview-based survey of experienced commercial harvesters׳ (1) perceptions of local trends in sea cucumber abundance, size, and fishing effort (CPUE), and (2) perceptions of management efficacy. The majority of harvesters perceived abundance (14/20) and CPUE (15/20) to have declined over their careers, and half of the harvesters reported decreased sea cucumber size. The harvesters most commonly cited overfishing as the most pressing problem facing the fishery (13/20), and the majority felt that Fisheries and Oceans Canada (DFO) needed to lower licence and/or area quotas to avoid further declines. Despite many knowledge gaps in the fishery, almost all harvesters (16/20) perceived that they are not adequately consulted and their concerns are not adequately considered by DFO. These results suggest a disjoint between DFO forecasts and perceived local sea cucumber trends, and highlight that the fishery may lack a resource-rights framework with adequate checks to decouple fishing pressure from increasing global market value and demand. Maintaining the long-term health of the BC sea cucumber fishery may depend on working more closely with harvesters to inform future management decisions and, ideally, moving towards a harvester-owned-and-operated licencing system that can better integrate the feedback that comes from attachment to place.     

The incentives of a resource owner: Evidence from a private oyster fishery

European flat oyster Ostrea edulis fisheries were once abundant around the UK coastline. The sole remaining productive O. edulis fishery in Scotland is in Loch Ryan. This fishery has been privately owned and managed by a single family since 1701. Economic theory predicts that ownership, whether public or private, is a necessary condition for rational fishery management. In this paper, a series of four leases and a licence are examined, covering an 85-year period over the 20th and 21st century, to examine whether the management of the Loch Ryan fishery conforms to the expected norms of rational management. The leases show that, over this period, the owners appear more willing to expend resources on regulating tenant behaviour, supporting the conclusion that successive generations of owners developed an evolving sense of what “rational management” might require. The results of this study could inform the management of other fisheries – both public and private – by emphasising the importance of learning from experience.     

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.     

The role of diversification in dynamic small-scale fisheries: Lessons from Baja California Sur,Mexico

Globally, small-scale fisheries are critical for livelihoods and food security yet face increasing uncertainty and variability from processes such as overfishing, globalization, and climate change. Enhancing the number of options for human response through increased access to marine resources, diverse livelihood approaches, and generalist fishing strategies may attenuate the negative effects of change and disturbance. My research explores the relative importance of diversification strategies for achieving resilient small-scale fishing communities and cooperatives of Baja California Sur, Mexico. Specifically, interview data and long-term catch and economic data were used to develop an economic metric of resilience, in addition to income diversification indices, for fishing cooperatives. Fishing cooperative characteristics and environmental conditions were then evaluated as possible predictors of cooperatives’ relative ability to diversify. I found that while diversification was important for risk mitigation and stabilizing income, the ability of cooperatives to specialize during favorable conditions may be important for poverty reduction and wealth accumulation. Thus, the flexibility to move across fishing strategies given changing environmental conditions is important for the adaptive capacity of small-scale fishing cooperatives. My findings will contribute to a better understanding of the institutional arrangements that promote a resilient small-scale fishery, and therefore, will be invaluable for practitioners of small-scale fisheries.     

Empowering NGOs? Long-term effects of ecological and institutional change on regional fisheries management organizations

The participation of environmental non-governmental organizations (ENGOs) in regional fisheries management organizations has inspired optimism among many observers and researchers about increasing the effectiveness of these regional organizations in managing highly migratory and straddling fish stocks sustainably. Others claim that the attendance of ENGOs in meetings of regional fisheries management organizations as accredited observers or as part of member state or cooperating non-member state delegations, could make decision-making complex, long, and inefficient. More generally, NGO participation has attracted broad scholarly interest in the study of interest groups and transnational advocacy in political science. Yet, we know little about the determinants of ENGO participation in meetings of regional fisheries management organizations in the first place. To fill this gap, this article develops a theoretical framework conceptualizing ENGO participation and developing expectations about how ecological and institutional change shapes ENGO participation. The framework deals with structural determinants of ENGO participation, as existing literature primarily has been preoccupied with the study of actor-specific explanations of specific NGOs’ impact in specific political processes. By contrast, we examine how ecological change – such as target fish stock health and biomass status – and institutional change – such as financial resources, membership composition of regional fisheries management organizations and participation by other non-state actors, such as experts and fishing industry representatives – shape ENGO participation. We empirically explore this framework in the context of seven regional fisheries management organizations. A dataset comprising yearly fish stock-level data on participation, institutional, and ecological factors, for 1980–2014, was compiled for our quantitative inquiry into the determinants of ENGO participation. We find robust evidence that institutional change shapes ENGO participation, but not ecological factors related to target fish stock health. We discuss our findings against the backdrop of ongoing debates about NGOs in political science, and spell out broader implications for future research on NGOs in regional fisheries management organizations.     

Basaltic thermals and Subplinian plumes: Constraints from acoustic measurements at Shishaldin volcano, Alaska

The 1999 basaltic eruption of Shishaldin volcano (Alaska, USA) included both Strombolian and Subplinian activity, as well as a “pre-Subplinian” phase interpreted as the local coalescence within a long foam in the conduit. Although few visual observations were made of the eruption, a great deal of information regarding gas velocity, gas flux at the vent and plume height may be inferred by using acoustic recordings of the eruption. By relating acoustic power to gas velocity, a time series of gas velocity is calculated for the Subplinian and pre-Subplinian phases. These time series show trends in gas velocity that are interpreted as plumes or, for those signals lasting only a short time, thermals. The Subplinian phase is shown to be composed of a thermal followed by five plumes with a total expelled gas volume of .The initiation of the Subplinian activity is probably related to the arrival of a large overpressurised bubble close to the top of the magma column. A gradual increase in low-frequency (0.01–0.5 Hz) signal prior to this “trigger bubble” may be due to the rise of the bubble in the conduit. This delay corresponds to a reservoir located at ≈3.9 km below the surface, in good agreement with studies on other volcanoes.The presence of two thermal phases is also identified in the middle of the pre-Subplinian phase with a total gas release of and . Gas velocity at the vent is found to be and for the Subplinian plumes and the pre-Subplinian thermals respectively.The agreement is very good between estimates of the gas flux from modelling the plume height and those obtained from acoustic measurements, leading to a new method by which eruption physical parameters may be quantified. Furthermore, direct measurements of gas velocity can be used for better estimates of the flux released during the eruption.     

An assessment of “fishing down marine food webs” in coastal states during 1950–2010

渔获物平均营养级（Mean trophic level of fishery landings,MTL）是目前评估人类捕捞活动影响的研究中使用最广泛的生物多样性指标之一。根据联合国粮农组织FAO提供的渔获生产统计数据,结合Fishbase提供的相关鱼种营养级数据,本文评估了1950-2010年太平洋、大西洋和印度洋各沿海国海洋渔业开发状态。研究发现,在全球三大洋75个主要捕捞国中,43个国家MTL呈显著下降趋势,发生了Pauly于1998年提出的“捕捞降低海洋食物网”现象;但是,仅16个国家MTL的下降是由于高营养级种类的衰退,而27个国家属于“捕捞沿着海洋食物网”的下降机制。此外,20个国家MTL呈恢复上升趋势,但是,该恢复上升趋势通常伴随着传统低营养级种类产量的大幅下降;在上述20个国家中,11个国家的低营养级鱼类产量呈显著下降趋势。需谨慎分析“捕捞降低海洋食物网”现象,掌握MTL的潜在变化机制。