Evaluation of Three Harvest Control Rules for Bigeye Tuna(Thunnus obesus) Fisheries in the Indian Ocean

The stock of Bigeye tuna(Thunnus obesus) in the Indian Ocean supports an important international fishery and is considered to be fully exploited. The responsible management agency, the Indian Ocean Tuna Commission(IOTC), does not have an explicit management decision-making framework in place to prevent over-fishing. In this study, we evaluated three harvest control rules, i) constant fishing mortality(CF), from 0.2 to 0.6, ii) constant catch(CC), from 60000 to 140000 t, and iii) constant escapement(CE), from 0.3 to 0.7. The population dynamics simulated by the operating model was based on the most recent stock assessment using Stock Synthesis version Ⅲ(SS3). Three simulation scenarios(low, medium and high productivity) were designed to cover possible uncertainty in the stock assessment and biological parameters. Performances of three harvest control rules were compared on the basis of three management objectives(over 3, 10 and 25 years): i) the probability of maintaining spawning stock biomass above a level that can sustain maximum sustainable yield(MSY) on average, ii) the probability of achieving average catches between 0.8 MSY and 1.0 MSY, and iii) inter-annual variability in catches. The constant escapement strategy(CE=0.5), constant fishing mortality strategy(F=0.4) and constant catch(CC=80000) were the most rational among the respective management scenarios. It is concluded that the short-term annual catch is suggested at 80000 t, and the potential total allowable catch for a stable yield could be set at 120000 t once the stock had recovered successfully. All the strategies considered in this study to achieve a ‘tolerable' balance between resource conservation and utilization have been based around the management objectives of the IOTC.

Composition and structure of species along altitude gradient in Moghan-Sabalan rangelands,Iran

This study provides a checklist of species distributed at the altitude gradient of MoghanSabalan rangelands in Ardabili province, Northwest Iran. We evaluated the changes in species composition, growth types of species, Raunkiaer's life forms, geographical distribution, threat and endemicity status, and palatability of species along two altitudinal gradients in the sampling plots, which were conducted in eleven sites/habitats with 300 meters above sea level(masl) altitude intervals(from 100 to 3300 masl). We assessed the plant species composition with special reference to the gradient analysis, and identified overall 396 species, which was comprising 44 families and 194 genera. Results showed that Asteraceae family is by far the most species-rich family, followed by Poaceae, Fabaceae, Caryophyllaceae and Brassicaceae. Among the genera, Astragalus is the most diverse genus, followed by Allium, Veronica and Bromus, Galium, Silene and Ranunculus. Results indicated that the number of species increased as the altitude increased to 1200-1500 masl, but then starts to decline to 3300 masl. Family-to-genera ratio was 1:4.4, the family-tospecies ratio was 1:9, and the genera-to-species ratio was 1:2.04. Growth type of species analysis shows that the frequency of perennial plants was higher in the study area followed by annual species while the lower group was biennial species. The number of annuals showed a decreasing trend towards higher altitude. Hemicryptophytes and therophytes were the most frequent life forms constituted each with(41.9%). Hemicryptophytes showed an increasing trend with altitude, while therophytes showed a decreasing trend with altitude increase, followed by geophytes, chamaephytes, and phanerophytes. Results showed more than half of the species of the study area belonged to Iran-Turanian region and these species showed an increasing trend with altitude. In contrast, Sahara-Sindian species comprise a minor component of the spectrum, with decreasing trend with altitude. The rare and endangered species out of the surveyed taxonomic groups comprised 53 species in total which 29 of them are considered lower risk(LR), 13 data deficient(DD), 5 vulnerable(Vu) and with 3 rare(R) and identified endemic plants comprised 24 species. Some 56.6% species were identified as class III, 22.6% were class I and 20.8% were class II as the palatability variation. Moghan-Sabalan rangelands require strong conservation management policies in case of species loss and changing natural communities due to the occurrence of conversion into cropland, over-grazing and other anthropogenic effects.

Local-Scale Governance： A Review of the Zambian Approach to Fisheries Management

Despite Zambia＇s recent policies for optimizing sustainable management of fisheries, their success has been modest in practice. Artisanal and industrial fleets have led to decline in fish catches in the presence of currently prescribed management possibilities. Among other factors, excessive fishing and unsustainable fishing methods attributed to common property and free access to the resources are key. The country adopted co-management approach to fisheries management in the 1990s with a view to improve the fisheries stocks through community enforcement of fishery management regulations. Neither the success of co-management has been easy to measure nor its results appreciated. In view of overfishing, it is required to continue providing a range of empirical evidence of area-specific co-management interventions as basis for designing realistic and innovative solutions for the nation. This implies that new policies and institutions need to be developed by research to understand fisheries systems and better promote sustainable trajectories. The following review recommendation to central government is a coherent approach that uses and crystallizes the multiple interests and skills of co-management stakeholders. Most stakeholder groups have been involved in an ad hoc fashion through workshops, public meetings and consultative processes mainly organized by Department of Fisheries. Stakeholders should be involved from the design of the process to each step in the process, including the ongoing monitoring and evaluation. A form of memorandum of understanding is suggested. This will formally set out a process that acknowledges each stakeholder＇s interests and provide forums to facilitate discussion, consultation and monitoring of management activities.

Extremist Politics as an Instrument of Ethnic Assertions among the Bodos of Northeast India

Ethnic assertions worldwide have assumed different forms ranging from moderate methods of articulation of autonomy to extremist means of violent struggle. Resort to extremism by some sections of an ethnic group usually triggers inter-ethnic conflicts with other groups on the one hand and leads to confrontation with the state on the other. This paper seeks to examine the dynamics of this phenomenon in the context of Bodos, the largest plains tribe of Assam, a State of Northeast India. The paper enquires as to whether extremist politics has met the Bodo aspirations for self-determination or has intensified the conflicts and contradictions within the Bodo society with ramifications for other ethnic groups inhabiting the Bodo-dominated areas. It is also necessary to explore the responses of the Union and State governments to Bodo extremist politics for an understanding of the conflict management process.

An Advanced Remote Sensing Mapping Technique Aimed at a Better Rainfall Water Preservation in Syria

The scarcity of water resources in Syria, due to its major arid to semi-arid climate （precipitation less 100 mm/year） in a large part of the country, imposes a better rainfall water management in the humid to semi-humid Syrian coast （precipitation over 1,000 mm/year）, where a high water quantity is lost in the sea. Various hydraulics constructions can be used aimed at a more rainfall water preservation： superficial wells, trenches, ponds, hilly lakes and small dams. Remote sensing techniques can help to build these constructions in places where the geomorphology is appropriate, and the filtration rate relatively limited. They are emplaced according to an advanced remote sensing mapping technique, based on the combination of several thematic maps： tectonics-, linear lineament （including density）, lithological facies drainage and filtration maps. This advanced mapping technique has been used to quantitatively verify ancient established constructions along the Syrian coast, and to propose optimal localizations for future hydraulics constructions. This technique presents a simple, quick and cheap solutions to be applied in Syria and the Arab world.

Managerial Overconfidence and Debt Decisions

The application of behavioural theory to corporate finance is now attracting the attention of theoretical work. However, very little rigorous empirical work has been carried out to analyse the desirability of behavioural biases in relation to financing decisions. The main results argue that managerial overconfidence provides an alternative determinant of capital structure. However, many questions remain to be explored, related to overconfidence measures and positive/negative effects of managerial overconfidence. Our paper assumes that the combination of financial theory and behavioural theory leads to better explanatory power. We follow two complementary goals. Firstly, we examine the dynamic trade-off model introducing a behavioural perspective. Secondly, we propose extending the pecking order analysis to incorporate overconfidence in Shyam-Sunder and Myers＇s model. We use a sample of Tunisian firms and employ panel-data estimation procedures to account for endogeneity and spurious correlation issues. Our results confirm the assumption that manager confidence is positively related to debt level. Overconfident managers underestimate the probability of financial distress and will choose higher levels of debt than they would if they were ＂rational＂.

加强和改进高校学风建设的思考

优良的学风不仅是一种氛围,也是一种动力,能促使学生树立远大的理想和明确的学习目的,培养勤奋乐学的学习态度,遵守严格的学习纪律。目前,在学生本人、学校的管理、社会大环境等方面,学风建设都遇到一些问题,为此,学校应从加强入学教育、培养学生的良好习惯,加强专业教育,提高学生的学习兴趣,多渠道合作,有重点地推进学风建设。