A spatio-temporal ecosystem model to simulate fishing management plans: A case of study in the Gulf of Gabes (Tunisia)

The Gulf of Gabes located in southern Tunisia is one of the most productive ecosystems in the Mediterranean Sea. Despite its ecological importance, it is subject to high fishing pressure affecting the different components of the ecosystem. Given the multispecies, multigear nature of the fishery, there is a need to manage trade-offs between environmental and economic objectives. In this study, an Ecospace model was developed based on the previously constructed Ecopath model of the Gulf of Gabes and calibrated for the period 1995–2008 to investigate the response of the ecosystem to a set of alternative spatial management scenarios. These scenarios were derived from the current fishery regulation owing the important interest expressed by local fishery managers to assess new management measures. The results showed for each management scenario how bottom trawling and coastal fishing impact the different trophic groups and the complexity of interaction between these two fishing activities. Furthermore, spatially explicit simulations were performed to identify regions where the management measures are effective. Results suggested that for some trophic groups, these regions are well-defined which would be interesting to propose more accurate spatial measures. Finally, several indicators were calculated to evaluate the proposed management plans and provide managers with a straightforward set of decision rules to describe the potential trade-offs and fulfill both fisheries and conservation management objectives in the context of an ecosystem approach. The decision rules were based on observed trends to reduce uncertainty relative to the model complexity and provide consistent advice to decision-makers.     

International fisheries regime effectiveness—Activities and resources of key actors in the Southern Ocean

Many contemporary environmental challenges are truly global and span several organizational and geographical borders. Research on international environmental regimes has, over the last couple of decades, identified several important factors that contribute to a more effective governance of global ecological resources, but few studies have addressed the different roles certain influential individual organizations play in determining regime effectiveness. Here we address this question by studying a relatively successful fishery governance system in the Southern Ocean. By drawing on insights from the research fields of common-pool resource management and international environmental regimes, we demonstrate that organizations engaged in certain combinations of activities, and that have access to certain combinations of resources stand out as important for regime effectiveness. In particular, collaboration with other flag states and being politically well-connected stand out as important explanatory factors. However, access to advanced technology, engagement in public campaigns, and being active in the field are other factors that, in different combinations, also seem to explain organizational importance. Furthermore, governmental and non-governmental organizations tend to perform different sets of activities and possess different resources, thereby complementing each other. Also, organizations doing similar things are often of different types with different mandates and objectives. This could contribute to improved adaptability and responsiveness to change at the larger regime level. Finally, we discuss some potential implications of our results for capacity-building in international environmental governance.     

Transferable Fishing Concessions (TFC): A pilot study on the applicability in the Mediterranean Sea

Fisheries management systems based on Transferable Fishing Concessions (TFC) and similar rights-based systems have been developed during the last decades in some European countries. However, at present there is not a clear view on the possible effects caused by the application of this management systems in the Mediterranean Sea. The current study, involving nine Geographical Sub-Areas (GSAs) of the Mediterranean Sea, focuses on the appropriateness, transferability and modes of applicability of a TFC system in the Mediterranean area. Three different scenarios of quota allocation have been analyzed by taking into account biological, ecological, environmental, economic and social aspects: quota in terms of resource quantity, quota as a portion of the total fishing time, quota as a portion of the total fishing capacity. Results show that the transferability of a TFC-based system to the Mediterranean context appears to be low due to the characteristics of the Mediterranean fisheries (multispecificity of resources, fishing grounds shared among different countries, multigear, importance of small-scale fisheries) and to the general lack of sound and reliable individual historical data. The study also highlights rights-based systems such as Territorial Use Rights in Fisheries (TURF) might only be applied for the exploitation of sedentary resources, such as clams. A management system based on TFC could be theoretically reasonable for anchovy fishing, where a few species are caught, even if all countries and stakeholders should be involved in the decision making process.     

Alaskan fishing community revenues and the stabilizing role of fishing portfolios

Fishing communities are subject to economic risk as the commercial fisheries they rely on are intrinsically volatile. The degree to which a community is exposed to economic risk depends on a community׳s ability to confront and/or alter its exposure to volatile fishery conditions through risk-reduction mechanisms. In this article, economic risk – as measured by community-level fishing gross revenues variability – is characterized across Alaskan fishing communities over the past two decades, and exploratory analyses are conducted to identify associations between community attributes and revenues variability. Results show that communities’ fishing portfolio size and diversification are strongly related to fishing revenues variability. Communities with larger and/or more diverse fishing portfolios experience lower fishing revenues variability. Portfolio size and diversification appear to be related to the number of local fisheries, indicating that communities’ portfolios may be constrained to the set of local fisheries. Hotspots of relatively higher fishing revenues variability for communities in north and west Alaska were identified, mirroring the spatial distribution of fishery-specific ex-vessel revenues variability. This overall pattern suggests that a community׳s fishing portfolio – and hence its exposure to risk – may be “predetermined” by its location, thereby limiting the policy options available to promote economic stability through larger and/or more diverse fishing portfolios. For such communities, diversifying income across non-fishing sectors may be an important risk reduction strategy, provided any potential negative cross-sector externalities are addressed.     

水产品合法性标签制度的法律属性及其立法完善

为促进我国渔业资源和水产品贸易的可持续发展,文章结合国际和国内的相关实践情况,分析我国水产品合法性标签制度的立法现状和存在的不足,尝试解答其中的关键问题即水产品合法性标签制度的法律属性,并就相关立法的完善提出建议。研究结果表明:水产品合法性标签制度是国际社会破解非法、不报告和不管制捕捞难题的重要制度,我国已开展相关实践并推动立法进程;目前我国水产品合法性标签制度的立法现状主要包括发布相关规范性文件和修订渔业法律,但该项制度在法律依据等方面仍存在不足;水产品合法性标签在法律上应被认定为强制标志,该项制度应属于强制性行政确认,且可适用于水产品国内贸易;在我国渔业法律的修订过程中,应通过健全实施程序和明确法律后果,进一步完善水产品合法性标签制度。     

《金史》《元史》天象记录的统计分析

在用现代天文计算方法全部检验的基础上,分类统计和分析《金史》和《元史》各种天象记录的数量和特征。统计中将所有天象记录分为可计算检验和不可计算检验2大类,并计算了各种记录的错误率,大多数错误记录可以考出其原貌。搜索了《金史》、《元史》以外的金元天象记录。     

A timely opportunity to protect North Atlantic right whales in Canada

The survival of federally protected North Atlantic right whales (Eubalaena glacialis) requires an immediate reduction in the risk of entanglement in commercial fishing gear. This paper argues that at least a 30% reduction in risk is needed to meaningfully contribute to the conservation of right whales. The argument follows from risk estimates calculated using time and space intersections of right whales and fishing gear in Canadian waters. Almost all the risk occurs during July, August and September (12%, 50%, 37% respectively) and the groundfish fishery contributed the greatest proportion (86%) of annual risk. Given that efforts in the USA to reduce entanglement risk through modified fishing gear have been unsuccessful to date, we address the alternative option of restricting certain fishing gear at times and locations where entanglement risk is elevated. There are many options that Canada could employ to achieve the above risk reduction and our results clearly point to the most effective and efficient action being seasonally restricted fishing in two relatively small regions; the Grand Manan Basin and the Roseway Basin. Fully a third (34%±4%) of the annual risk is associated with these two basins, though fishery catch estimates in the basins are relatively small and declining.     

The long-term impacts of fisheries on epifaunal assemblage function and structure, in a Special Area of Conservation

Fisheries can have profound effects on epifaunal community function and structure. We analysed the results from five dive surveys (1975-1976, 1980, 1983, 2003 and 2007), taken in a Special Area of Conservation, Strangford Lough, Northern Ireland before and after a ten year period of increased trawling activity between 1985 and 1995. There were no detectable differences in the species richness or taxonomic distinctiveness before (1975-1983) and after (2003-2007) this period. However, there was a shift in the epifaunal assemblage between the surveys in 1975-1983 and 2003-2007. In general, the slow-moving, or sessile, erect, filter-feeders were replaced by highly mobile, swimming, scavengers and predators. There were declines in the frequency of the fished bivalve Aequipecten opercularis and the non-fished bivalves Modiolus modiolus and Chlamys varia and some erect sessile invertebrates between the surveys in 1975-1983 and 2003-2007. In contrast, there were increases in the frequency of the fished and reseeded bivalves Pecten maximus and Ostrea edulis, the fished crabs Cancer pagurus and Necora puber and the non-fished sea stars Asterias rubens, Crossaster papposus and Henricia oculata between the surveys in 1975-1983 and 2003-2007. We suggest that these shifts could be directly and indirectly attributed to the long-term impacts of trawl fishing gear, although increases in the supply of discarded bait and influxes of sediment may also have contributed to changes in the frequency of some taxa. These results suggest that despite their limitations, historical surveys and repeat sampling over long periods can help to elucidate the inferred patterns in the epifaunal community. The use of commercial fishing gear was banned from two areas in Strangford Lough in 2011, making it a model ecosystem for assessing the long-term recovery of the epifaunal community from the impacts of mobile and pot fishing gear.     

Fishermen's perspectives on climate variability

Understanding fishermen's perspectives and responses relating to climate variability is important for sustainable fisheries management. To this end, a survey of captains of commercial passenger fishing vessels (CPFVs) was conducted in San Diego. The survey demonstrates that fishermen have observed and adapted to changes in the environment and fish populations associated with climate variability. However, only 12.9% of respondents agreed that global climate change is a possibility. In order to explain fishermen's divergent beliefs on climate change, a semiparametric discrete choice model is used to identify the potential determinants. The empirical results highlight the importance of the following factors: fishermen's experience, observations of the phenomena that are associated with climate variability, and an interaction of fishermen's experience and their observations.     

基于国际法的跨境水分配关键指标及其特征

基于《国际淡水条约数据库》及1999 年以来相关跨境水资源利用与管理的研究成果,通过综合分析1864-2002 年49 个跨境水分配条约中的6 类28 项分水指标的区域与演进特征,判识跨境水分配的关键指标,结果表明：分水指标在实践中存在着明显的区域差异,在欧美发达地区的分水主要指标首先是维持最小水量,其次是多年平均水量,而亚非及南美洲欠发达地区则反之;少水区河流水分配的主要指标是多年平均水量和维持最小水量指标,而多水区河流则是维持最小水量和最大取用水量指标;从1864-2002 年分水条约签订的4 个历史时期上看,条约数量呈现少-多-较少-持平的变化趋势,条约的区域分布呈现出从欧美地区向亚非地区转移特征;主要分水指标从最早的维持最小水量和多年平均水量指标,演变到维持最小水量和最大取用水量指标,再到水利设施运行和多年平均水量,至最近的维持最小水量和多年平均水量指标,主要指标具有变化往复特点.综合跨境水分配条约中主要指标在不同时期及不同地区应用特征,可确定跨境水分配的关键指标为维持最小水量指标.