The role of environmental and fisheries multi-controls in white seabream (Diplodus sargus) artisanal fisheries in Portuguese coast

Evaluating the effects of fishing and environmental factors on fish populations are fundamental tenets of fisheries science. In this study, we assess associations between environmental variables (sea surface temperature; North Atlantic Oscillation index; upwelling; wind magnitude; westerly winds; northerly winds; river discharge) and fishing variables (fishing effort) in Diplodus sagus catch rates accounting for regional analyses (northwest coast; southwest coast and Algarve—Algarve south coast). Different time series models for data fitting (multi-model approach) were used. The models were lagged, according to species fishing recruitment age based on the hypothesis that fisheries catches depend on larvae recruitment and survivorship. D. sargus catch rates across areas were unrelated to fishing effort but correlated to environmental variables, with seasonal events explaining much of the variability in trends. On the northwestern coast, the catch rates were mainly set by sea surface temperature (SST) and wind magnitude; however, southwestern coast catch rates were set by NAO winter. On the south coast, only one statistical model (SST, upwelling and westerly winds) associated spring conditions with D. sargus catch rates. The multi-model approach revealed autumn, winter and spring seasonal effects to be related with northwest, southwest and Algarve coastal catch rates, respectively, indicating a possible coastal longitudinal gradient related with given periods of spawning and larval availability. The metadata analysis yielded different results from the regional analyses. In summary, marine resource management should take regional environment characteristics and variability into account when determining sustainable catch rates in given areas for species with high habitat site fidelity.     

Adapting to declining fish resources: the differentiation of livelihood systems and fishing strategies in Singkarak Lake’s fishing community,West Sumatra

In Southeast Asia, inland fish resources are crucial for small-scale fishing households. Their decline, due to overfishing and a set of socio-ecological factors, jeopardises aquatic ecosystems and the livelihoods of fishing communities. Singkarak Lake (West Sumatra) exemplifies this sustainability challenge. The paper proposes a multi-disciplinary analysis of the situation. First, it identifies and documents the primary livelihood systems and the strategic adaptations involved in fishing communities. Based upon a sample of 200 households and the implementation of multivariate analyses, a typology is developed. Three household types are identified. Type I comprises better-off farming fishers that have high fishing capitals and income but the lowest returns on fishing and land assets. Type II includes poor fishing farmers with higher farming income; they show the highest return on land assets. Type III is composed of poorer, younger fishers with the highest return on fishing assets and fishing costs. They have little land, low farming income, and diversified livelihood sources. Second, the technical efficiency (TE) of fishing households is studied using a data envelopment analysis. The results show that the average TE is low, but marked differences exist between the types. Type I households have the lowest TE in fishing, confirming an extensification and overcapitalisation strategy. Type II households show a high technical fishing efficiency. They have developed on-farm diversification with a combined, balanced livelihood system. Type III households are the most efficient fishers. They developed an intensification strategy together with off-farm diversification. Different livelihood strategies and economic portfolio have been developed as the response to the limited resources, uncertainty, fluctuating environment and other source of vulnerability. The fishers built up their livelihood based on their assets’ ownership, access to other resource out of fishing and their socio-economic status. In this context, understanding livelihood diversity among small-scale fishers, different socio-economic, their efficiency, constraints and opportunities emerge as important factor in policy formulation to enhance support to small-scale fishing communities and improved management of both the resources and local development. Finally, the paper suggests a focus on people and community-related solutions and proposes a threefold approach of resource conservation, livelihood improvements and restructured governance.     

Heterogeneity, collective action and management sustainability in common property forest resources: case study from the Indian state Odisha

Several studies have revealed that the presence of heterogeneity amongst the user groups of common property natural resources considerably affects the effectiveness of resource management and their sustainable use. Primary research conducted in six sample villages from three districts of the Indian state Odisha has found that heterogeneity in economic and social dimensions amongst the members of the management committee acts as major determinants in respect of common property forest resource management. The findings of this piece of work reveal that common property forests are best managed in the villages where the management committee is homogeneous by both social and economic considerations; better managed where the committee members are economically homogeneous but socially heterogeneous; and least managed where the members are socially homogeneous but economically heterogeneous. The same result has been obtained from the composite index developed for the user group’s assessment about the functioning of the forest management institutions in the three study districts of the state Odisha.     

Invasive alien species as drivers in socio-ecological systems: local adaptations towards use of Lantana in Southern India

Lantana camara. L (hereafter Lantana) was first introduced by the British into India in 1807 as an ornamental plant. Since then the species has spread across the length and breadth of the country. Attempts to control Lantana in India have not been successful. In this study, we analysed the use of Lantana by local communities in southern India and identified the possible causes and consequences of its use through the use of a household survey of the socio-economic profile of the user and nonuser households and an analysis of the ecological history of the communities. Communities have been using Lantana for over 25–30 years and apparently such use was not prompted by external agencies. The characteristics of user and nonuser households were similar, except that Lantana users were more literate and had a greater number of occupations per household than nonusers. Per capita income was similar between user and nonuser groups. For nonuser groups, their main income sources were from trading (44 %), wage labour (32 %) and forest resources (23 %). In contrast, the Lantana user groups substituted their loss of income from forest resources (7 %) by income from Lantana (46 %). The ecological history revealed that Lantana was adopted as a resource at a time when it was increasing in the landscape and traditional bamboo resources were in decline because of overuse by commercial enterprises and mast flowering. This change in ecological resource availability prompted a major shift in livelihoods for some in the area.     

Fishers’ perceptions of climate change,impacts on their livelihoods and adaptation strategies in environmental change hotspots: a case of Lake Wamala,Uganda

Fisheries resources support livelihoods of fishing communities but are threatened by over-exploitation, habitat degradation, pollution, invasive species and climate change. Unlike the other threats, climate change has received limited consideration and reducing its risks requires appropriate adaptation strategies. This study used quantitative and qualitative methods to generate knowledge on fishers’ perceptions of climate change, changes in climate variables and their impacts on livelihoods, adaptation strategies, constraints to adaptation and required interventions to promote adaptation strategies that would enable fishers to build resilience to sustain their livelihoods. We found that fishers were aware of changes in climate conditions manifested by unpredictable seasons, floods and droughts. Fishing remained the main livelihood activity. However, the dominance of fishes had changed from Nile tilapia (Oreochromis niloticus L.) to the African catfish (Clarias gariepinus Burchell). Floods and droughts were associated with damage to gears, boats, landing sites and changes in fish catches and sizes, income from fishing and fish consumption. The fishers adapted by increasing time on fishing grounds and changing target species and fishing gear among other things. Some innovative fishers diversified to high-value crops and livestock. This increased their income beyond what was solely earned from fishing which provided an incentive for some of them to quit fishing. Livelihood diversification was enhanced by use of communications technology, membership of social groups, increasing fishing days and fishing experience. Adaptation was, however, constrained by limited credit, awareness and access to land, which require interventions such as improving access to credit, irrigation facilities, appropriate planting materials and awareness raising. We identified adaptation strategies, which if promoted and their constraints addressed, could increase resilience of fishers to the influence of climate change and sustain their livelihoods.     

Assessing concentrations and health impacts of air quality management strategies: Framework for Rapid Emissions Scenario and Health impact ESTimation (FRESH-EST)

In air quality management, reducing emissions from pollutant sources often forms the primary response to attaining air quality standards and guidelines. Despite the broad success of air quality management in the US, challenges remain. As examples: allocating emissions reductions among multiple sources is complex and can require many rounds of negotiation; health impacts associated with emissions, the ultimate driver for the standards, are not explicitly assessed; and long dispersion model run-times, which result from the increasing size and complexity of model inputs, limit the number of scenarios that can be evaluated, thus increasing the likelihood of missing an optimal strategy. A new modeling framework, called the “Framework for Rapid Emissions Scenario and Health impact ESTimation” (FRESH-EST), is presented to respond to these challenges. FRESH-EST estimates concentrations and health impacts of alternative emissions scenarios at the urban scale, providing efficient computations from emissions to health impacts at the Census block or other desired spatial scale. In addition, FRESH-EST can optimize emission reductions to meet specified environmental and health constraints, and a convenient user interface and graphical displays are provided to facilitate scenario evaluation. The new framework is demonstrated in an SO₂ non-attainment area in southeast Michigan with two optimization strategies: the first minimizes emission reductions needed to achieve a target concentration; the second minimizes concentrations while holding constant the cumulative emissions across local sources (e.g., an emissions floor). The optimized strategies match outcomes in the proposed SO₂ State Implementation Plan without the proposed stack parameter modifications or shutdowns. In addition, the lower health impacts estimated for these strategies suggest that FRESH-EST could be used to identify potentially more desirable pollution control alternatives in air quality management planning.     

雅鲁藏布江异齿裂腹鱼生活史对策和种群资源利用现状

2008年8月至2009年8月在西藏雅鲁藏布江中游采集到异齿裂腹鱼（Schizothorax oconnori）1 126尾,对其生活史对策和种群资源利用现状进行了研究。结果显示：异齿裂腹鱼的总死亡系数（Z）雌性为0.090/a,雄性为0112/a;自然死亡系数（M）雌雄分别为0053/a和0064/a;捕捞死亡系数（F）雌雄分别为0037/a和0048/a;开发率（E）雌雄分别为0415/a和0428/a。以达氏鳇（Huso dauncus）和尖头塘鳢（Eleotris oxycephaoa）作为参照物,运用模糊聚类进行分析,表明异齿裂腹鱼属于比较典型的K 选择类型鱼类。在现捕捞死亡系数、现起捕年龄和现自然死亡系数下,异齿裂腹鱼的繁殖潜力比雌雄分别为5280%和5164%,都大于目标参考点40%。通过单位补充量亲鱼生物量模型分析,显示目前雅鲁藏布江中游异齿裂腹鱼种群资源的开发水平较为合理     

Belief Networks: A Framework for the Participatory Development of Natural Resource Management Strategies

Successful long-term management of natural resources requires the development of strategies which recognise the constraints pertaining to the environmental system and can therefore be realistically expected to work. This paper presents a new technique for strategy formulation using belief networks, a framework based on Bayesian probability calculus that supports the investigation of complex environmental systems by the user and analysis of all constraints. While mathematical in nature, belief networks are superficially simple and allow concepts to be expressed in terms with which a wide range of user will be familiar. This offers a participatory approach to the development of management strategies through consideration of the impact of potential management options with consequent benefits for strategy implementation.     

Artisanal fishers’ ethnobotany: from plant diversity use to agrobiodiversity management

Artisanal fishers interact with plants in many ways, and with different intensities. In spite of being characterized by fisheries, Caiçaras use plants with varied degrees of management, since the less intensive management actions, extraction of forest products, until intensively management actions through the cultivation of the agrobiodiversity. This study presents the results of different research projects and includes the North and the South regions of São Paulo state coast. The objective is to characterize the diversity of extracted and cultivated species by traditional fishers at Southeastern region of Brazilian Atlantic forest. Ethnobotanical surveys revealed a high diversity of plants known and used, ranging up to a richness of 272 species known in two communities for the South coast, most of them being native. However, depending on the management intensity, this diversity can be rather particularized: we found 68 varieties of cassava (Manihot esculenta Crantz) at North region and 58 varieties at the South region, with exclusive vernacular names. Through an ethnobotanical perspective, we compare and discuss the different dynamic systems underlying the relationships between fishers and plants. The diversity of cultivated plants is analyzed in depth, focusing on the historical importance of agriculture among people who are currently characterized as fishers. A schematic model is proposed to explain the dynamic systems operating in the relationships between fishers and plants.     

Using a novel climate–water conflict vulnerability index to capture double exposures in Lake Chad

Climate variability is amongst an array of threats facing agricultural livelihoods, with its effects unevenly distributed. With resource conflict being increasingly recognised as one significant outcome of climate variability and change, understanding the underlying drivers that shape differential vulnerabilities in areas that are double-exposed to climate and conflict has great significance. Climate change vulnerability frameworks are rarely applied in water conflict research. This article presents a composite climate–water conflict vulnerability index based on a double exposure framework developed from advances in vulnerability and livelihood assessments. We apply the index to assess how the determinants of vulnerability can be useful in understanding climate variability and water conflict interactions and to establish how knowledge of the climate–conflict linked context can shape interventions to reduce vulnerability. We surveyed 240 resource users (farmers, fishermen and pastoralists) in seven villages on the south-eastern shores of Lake Chad in the Republic of Chad to collect data on a range of exposure, sensitivity and adaptive capacity variables. Results suggest that pastoralists are more vulnerable in terms of climate-structured aggressive behaviour within a lake-based livelihoods context where all resource user groups show similar levels of exposure to climate variability. Our approach can be used to understand the human and environmental security components of vulnerability to climate change and to explore ways in which conflict-structured climate adaptation and climate-sensitive conflict management strategies can be integrated to reduce the vulnerability of populations in high-risk, conflict-prone environments.     

长江靖江段沿岸似鳊生长及种群参数估算

2012年1月~2013年12月连续24个月在长江靖江段沿岸收集似鳊标本2 334尾,采用基于体长频率数据的ELEFAN I技术估算长江近口段沿岸似鳊的生长参数与种群参数。结果表明:似鳊体长(L,cm)与体质量(W,g)幂函数关系为:W=0.0182×L~(2.948)(r=0.9823,n=2334)。Von Bertalanffy生长方程描述的似鳊生长参数为:极限体长(L_∞)=19.25 cm,生长系数(K)=0.2/a,理论生长起点年龄(t_0)为-1.59 a,体质量的生长拐点年龄为3.55 a。采用Pauly的经验公式估算似鳊自然死亡系数(M)为0.556/a。由长度变换渔获曲线法估算出的似鳊总死亡系数(Z)为1.638/a,捕捞死亡系数(F)和开发率(E)分别为1.082/a和0.66/a。2012~2013年长江靖江段沿岸似鳊年均资源重量和资源数量分别为120.59 t和947.4万尾。经相关估算参数和相对单位补充渔获量分析得出,当前长江靖江段沿岸似鳊已处于过度捕捞状态。建议将沿岸水域禁渔期延长至9月(即4~9月),以实现似鳊资源的恢复和可持续发展。     

春季禁渔对常熟江段渔业群落结构及物种多样性影响的初步研究

以2000~2004年4~6月渔业资源动态监测资料为依据,分析研究了3年春季禁渔(2002~2004)对常熟江段渔业资源群落结构及物种多样性的影响。研究结果表明：4~6月间常熟江段出现的鱼、虾、蟹类渔获物共有11目、18科、46种;春禁后,该江段总CPUE（单位捕捞努力渔获量）显著增加;优势种更替不明显,历年以刀鲚、鲻鱼、长春鳊等经济鱼类为主;刀鲚CPUE有所回升,资源衰退受到遏制;小型鱼类、幼鱼在渔获物中的比例明显上升; Margalef物种丰富度指数、Wilhm改进指数呈明显上升趋势,均匀度指数J′、优势度数Dw在窄幅范围波动。春禁对常熟江段渔业资源保护的生态效果较明显,春禁后渔业资源群落种间结构得到一定程度的改善,生物多样性上升。     

Integrated models for environmental management: Issues of process and design

Integration has become an important element of natural resource management over recent decades, and managers are now required to consider the social, economic, ecological, and bio-physical effects of alternative management interventions. The problem of managing across many issues is sometimes tackled by putting together a number of individual models. For this approach to work effectively, attention must be paid to both the technical details of the interactions between system components and also to the processes through which these integrated models are developed. This paper explores technical and social aspects of the development of integrated models for environmental management, and discusses two cases within which open modelling and interface prototyping processes were undertaken. The results of this exploration suggest that, for models to be used and accepted widely in integrated environmental management, developers must undertake a process that involves stakeholders and potential users, that exploits the current knowledge, and that illustrates the influence of uncertainty in the technical knowledge. This requires strict attention to the social and technical process of modelling, as well as additional skills in group facilitation and shared vision exploration, so that user expectations can be developed and met in such a way that the best information available is used by decision makers.     

Resource management for sustainable development: a community- and GIS-based approach

A combined approach utilizing GIS, Participatory Rural Appraisal (PRA) and Focus Group Discussion (FGD) has been developed for resource mapping in a rural poverty-prone area of Bangladesh. This model integrated GIS and participatory tools to include the voices of the stakeholders in assessing available resources and needs. The resource mapping framework, developed using PRA with local community people and community gatekeepers, was aimed at sustainable resource management, and ArcView GIS was used to digitize the resource maps as a Decision Support System (DSS). A detailed assessment and analysis of the quality, quantity and physical status of resources was first mapped in the field and then digitized using GIS. FGD-based interaction with community people at each union in a subdistrict of Bangladesh revealed stakeholders’ opinions on land and water body management. The present paper demonstrates the power of this model as a policy-making tool for sustainable development and poverty eradication. It also recognized the need for collaboration between interdisciplinary policy planners and researchers to develop and implement a policy on agricultural resource management for poverty-prone areas.     

长江靖江段刀鲚捕捞量的时间变化及相关环境因子分析

江苏靖江段位于长江近口段,是长江刀鲚渔汛最集中的水域。调查了靖江段2008、2009、2012~2015年6个渔汛期的捕捞数据,采用广义可加模型(GAM模型)分析了刀鲚捕捞量与靖江段表层水温、潮差、气压、降水量、浑浊度、CODMn等环境因子之间的相关性。调查显示,靖江段每年发放刀鲚专项渔业捕捞证84~95本,平均年作业天数28~43 d,2012~2015年的作业天数比2008~2009年明显下降。6个渔汛期刀鲚的年捕捞量变幅为3.71~17.38万尾和3.61~18.26 t,除2013年外,年捕捞量总体上仍呈下降趋势。采用GAM模型对10艘持证渔船的刀鲚日捕捞量与环境因子之间的相关性分析显示,日捕捞量随水温的升高而递增,汛期78.8%的产量在15~23.2℃水温范围获得。而当水温低于10℃时,空网率上升,仅获得5.7%的汛期产量。表明当水温不足10℃时,刀鲚可暂时停止其生殖洄游过程。分析还显示,69.1%的汛期产量在2.0 m以上的大潮差期获得,表明潮汐亦是影响刀鲚日捕捞量的重要因子。低浊度及气压、降水量、CODMn等对刀鲚的日捕捞量无显著性影响,但当浊度大于100 NTU时,日捕捞量迅速降低。可见,水温、潮差和高浑浊度是影响长江靖江段汛期刀鲚捕捞量的关键环境因子。     

长江口溯河鳗苗开发率估算

利用长江口南支上段东风西沙调查站位(121°15′45′′E;31°40′18′′N)2015年度鳗苗捕捞数据,通过CPUE波动趋势分析,确定当年日本鳗鲡鳗苗溯河汛期特征;进而采用Leslie和Delury两种方法估算东风西沙站位鳗苗资源指标。结果显示,2015年度东风西沙站位出现6个明显的鳗苗补充汛期,两种方法估算的汛期波动规律一致。各汛期捕捞持续时间5~27 d,平均为10.17 d。Leslie法估算的各汛期捕捞开发率43.38%~96.30%,平均77.14%;Delury法估算结果为43.36%~105.37%,平均81.43%;均为较高水平。高开发率表明东风西沙水域樯张网作业方式致使溯河迁移鳗苗处于高度开发状态,减少溯河鳗苗数量,影响长江流域成鳗资源。Leslie法估算日捕捞死亡系数和日捕捞死亡率平均值分别为0.23和20.02%,均分别低于De Lury法估算平均值0.27和22.79%;捕捞死亡系数将为采用年渔获量估算鳗苗资源量提供基础数据。     

Conditions for successful local resource management: lessons from a Brazilian small-scale trawling fishery

Conditions for successful common-pool resources management institutions have been systematized by Elinor Ostrom as a set of “design principles for robust governance”. The comparison of two attempts to developing a local informal managing institution for shrimp trawling, 30 years apart (the late 1970s and 2010 attempts), and in the same community (therefore, the same socioecological system—SES) in Southern Brazil, provides a convenient ground to test the hypothesis that the degree of success of each attempt is related to the degree of adherence to Ostrom’s principles. Moreover, the comparison allows investigating how conditions and changes in the SES affect management institutions. Our institutional analysis showed that the 1970s attempt followed a local rule that best fitted almost all principles, which may explain its relative success and longer-lasting activity. However, changes such as the emergence of new technologies and increased fishing activity gradually led to an erosion of the local rule. A low level of group cohesion, regional socioeconomic changes, increased fishing effort, and lack of legal provisions for fishers to develop local managing institutions were the main factors that led to institutional failure in the two evaluated attempts. Additionally, the lack of ability to adapt to changing conditions weakened the continuity of the management regime. Although Brazil has created new fishery co-management policies, strategies to enable institutions at local levels are urgently needed for improved performance.     

Female territoriality in small rodents: Interrelations with local population persistence

Samples of small rodent populations inhabiting Crabapple Island on Beldany Lake in NE Poland revealed that Clethrionomys glareolus was continously present there, whereas Apodemus flavicollis and Microtus agrestis appeared, stayed for some period, vanished and reappeared. It appears that sexually mature females of the bank vole are strictly territorial, their numbers are limited, and immature individuals hardly disperse at high population size. Sexually mature females of the yellow-necked mouse seem to be territorial only at low population numbers, and their numbers increase linearly with population size. Sexually mature females of the field vole exhibit high level of aggregation, and their numbers increase in streight line with growing population size. We discuss the idea that different social organization of the rodent populations is connected with various strategies (sedentary and nomadic) supporting local population persistence.     

三峡蓄水后长江口凤鲚汛期生物学特征及捕捞量变动

分别在长江南支南门至新河水域、北港水域和圆沙至九段沙水域设置调查断面，对三峡蓄水后（2003~2011年）长江口凤鲚汛期生物学特征、渔汛特征及捕捞量进行了持续调查，并将之与蓄水前（1997~2002年）调查数据进行了对比研究。调查期内凤鲚汛期绝对怀卵量变幅为3 404~26 850粒，平均为11 554粒；相对怀卵量变幅为347~1 582粒/g，平均为783粒/g；卵径变幅为053~106 mm，平均为078 mm。凤鲚全长变幅为139~155 mm，平均为146 mm；体长变幅为123~137 mm，平均为129 mm；体重变幅为120~158 g，平均为136 g；丰满度系数变幅为0387~0466，平均为0442。2003~2011年凤鲚全长小于140 mm的个体所占比例均值为3691%，140~180 mm的个体占比为5706%；体重小于12 g的个体占比为3957%，12~20 g的个体占比为4534%。长江口凤鲚渔汛出现时水温通常介于17℃~20℃，5月中下旬至6月中旬为旺汛期，各年5月捕捞量占比变幅为3059%~8376%，平均为6117%。调查期间长江口凤鲚汛期捕捞船数量变幅为63~278艘，平均为141艘；单船全汛捕捞量变幅为3679~5 0235 kg，平均为2 4412 kg；汛期总捕捞量变幅为232~1 2569 t，平均为4223 t。三峡蓄水后长江口凤鲚渔获规格和捕捞量均出现了不同程度的下降，与历史记录相比，其资源几近枯竭，捕捞价值基本丧失。建议立即对凤鲚实施禁捕，并尽快建立繁殖场和越冬场保护区。     

Some limitations of biological monitoring

Biological monitoring data are obtained to document changes in population abundance for resource management, to verify compliance with regulatory directives, and to assess cause and effect for research purposes. Particular statistical analyses are often not appropriate because suitable field designs are either not available or not matched a priori to the monitoring objectives. When monitoring to detect normal changes in population numbers, quantitative problems may not be as difficult as they are in detecting and assigning causation induced by a natural or man-made pollutant. Changes in biotic abundance can be caused or influenced by compensation, indirect effects, direct mortality, and interactions among environmental variables. Even though data from baseline monitoring programs should usually only be used to detect change in biotic abundance, they sometimes can be used to draw inferences about cause by correlation or to test laboratory results against a long-term historical record. Available quantitative methodologies useful in evaluating monitoring data are limited and interpretations about cause and effect are difficult.