Social control of growth in Macrobrachium rosenbergii (De Man): a review and prospects for future research

The wide range of sizes of sexually mature prawn populations and particularly of the males is very typical of Macrobrachium rosenbergii (De Man) and a major obstacle to increased profitability of prawn culture. Prawn size variation reflects a complex population structure composed of three major male morphotypes – the small males, the orange‐claw males and the blue‐claw males – which differ in their morphology, physiology and behaviour. Social interactions among juveniles and among sexually mature males affect their growth. Four different social mechanisms have been suggested to control growth in crustaceans: direct competition for food, appetite suppression, altered food‐conversion efficiency and increased energy expenditure on motor activity. Since all growth‐controlling mechanisms involve an aggressive behavioural component, our knowledge of prawn agonistic behaviour and prawn social organization has been reviewed. Present knowledge of the social mechanisms regulating growth among juveniles and among sexually mature male morphotypes as well as the sensory modalities involved was evaluated. The possible evolution of social growth‐controlling mechanisms is discussed. Various ways for implementing our knowledge on social control of growth into prawn culture to increase profitability are suggested.     

Tracking public interest and perceptions about smalltooth sawfish conservation in the USA using Instagram

1. The population of smalltooth sawfish (Pristis pectinata) in the USA was listed as endangered under the US Endangered Species Act in 2003. Based on objectives identified in the Smalltooth Sawfish Recovery Plan, an interdisciplinary team developed a variety of outreach efforts and products to educate the public and promote sawfish conservation. These include safe viewing, handling, release, and reporting guidelines for boaters, divers, and anglers that may interact with the species.
2. The usefulness of monitoring social media to track public interest and perceptions of smalltooth sawfish was investigated via Instagram posts mentioning sawfish encounters in the USA. We aimed to identify how current outreach efforts and messaging can be improved and expanded to better inform the public and promote positive change in their behaviour to further protect smalltooth sawfish.
3. All encounters occurred in Florida waters and the trend of sawfish-related Instagram posts increased congruently with traditionally reported sawfish encounters from 2012 to 2019. The number of Instagram users who indicated that they reported their encounter or that any sawfish encounter should be reported has increased, suggesting outreach efforts have gained traction and that some members of the public are actively promoting sawfish conservation through encounter reporting. The overall tone, and thereby public perception of and attitude towards sawfish, was largely positive.
4. Though social media can be used to guide outreach initiatives and provides a platform for researchers to engage large public audiences, future research efforts should include electronic surveys within the recreational, commercial, diving, and angling communities. Additionally, social media posts should be compared with traditionally reported encounters, and media professionals working with scientists should focus on increasing the utility of social media as a way to collect encounter reports and create engaging educational content to be included with continued outreach efforts throughout the south-eastern USA.

     

A country's response to tackling plastic pollution in aquatic ecosystems: The Chilean way

1. Marine plastic pollution is worse than expected, and we are starting to realize its full extent and severity. Solving the plastic pollution problem is not easy, as it requires the action and commitment of all sectors of our society. With a coastline extending over 4,000 km (from 18°S to 56°S), Chile is a maritime country, and since plastics are potentially harmful for marine and coastal ecosystems, food security, and public health, plastic pollution is a real threat.
2. Chile is the sixth-largest exporter of seafood (fish, invertebrates, and algae) in the world, but the extent of plastic contamination of marine organisms, its potential effects on commercial species and aquaculture, and its subsequent effects on human health are mostly unknown.
3. Chile has recently introduced some legislation to prevent plastics from reaching the environment and the coastal ocean. Governmental and non-governmental organizations have joined an informal alliance to take action against plastic pollution, both at a national and regional level, but stronger involvement of producers and commerce is required for effective measures.
4. Chilean scientists working on plastic pollution have created the Scientific Plastic Pollution Alliance of Chile network, aiming to promote collaborative and coordinated research focused on this pollutant. The wide geographical extent of Chile, with researchers working in diverse ecosystems, provides a unique opportunity to better understand the consequences of one of the most recent and severe threats to biodiversity.
5. Rather than solely presenting the plastic pollution problem from the scientific perspective, this paper includes views from different sectors of society. Mitigating plastic pollution is exceptionally complex, with this study highlighting the importance of local engagement, media, solving social inequities, new legislation, and law enforcement in order to advance on decreasing plastic pollution from a country-wide perspective.

     

Just Aquatic Governance: The Amazon basin as fertile ground for aligning participatory conservation with social justice

1. Governance of natural resources in the Amazon has changed over time, especially when it comes to participatory regimes. Yet these regimes have rarely focused on the conservation of aquatic systems or have failed to fully deliver social justice.
2. Participatory regimes in the Amazon basin that rely on the provision of freshwater ecosystem services can potentially favour transformative and just conservation. A framework referred to as the ‘Just Aquatic Governance’ model is proposed to organize and facilitate the transition of continuing and future endeavours that seek conservation while also supporting distinct aspects of social justice.
3. If conservation of aquatic systems can be reconciled with all aspects of social justice, then transformative and just governance regimes could emerge without further burdening those at the forefront of conservation.
4. The Just Aquatic Governance framework is divided into three aspects of social justice, organized according to the following pillars: (i) recognitional – support for cultural diversity and the maintenance of livelihoods, including food security; (ii) procedural – the right to autonomy and territory, and support for participatory forms of governance; and (iii) distributional – promotion of gender equality and fair distribution of economic benefits.
5. Although not a panacea, the model proposed here, which can also influence policy strategies, can potentially align both conservation demands and social aspirations in the Amazon – a historical, yet still imperative, need in the region.

     

Aquaria and marine environmental education

Marine aquaria claim that they help to elevate the current low profile of marine conservation through public education. The effectiveness of aquaria as centres for marine conservation education was assessed using social survey techniques, at three large commercial aquaria in the south-west of England. The aquaria managers did not believe that most visitors were interested in receiving educational information, in particular on conservation topics. Textual analysis revealed that aquaria's interpretative material contained very few references to conservation and portrayed a distorted image of the marine environment. The feedback from the questionnaires revealed no evidence for an increase in visitors' sympathy towards and understanding of marine conservation following a visit to an aquarium. The majority of visitors wanted public aquaria to increase their levels of interpretation. In particular, visitors wanted more information on conservation and how they, as individuals , could contribute to preserving the marine environment. As well as benefiting conservation, increasing the educational impact of aquaria could have significant commercial advantages, e.g. increased visitor satisfaction and numbers. Suggestions on how these mutual benefits could be achieved are briefly outlined. Their success will depend on the degree of cooperation which can be forged between commercial aquaria and conservationistsThis revised version was published online in October 2005 with corrections to the Cover Date.     

Vulnerability of the biota in riverine and seasonally flooded habitats to damming of Amazonian rivers

1. The extent and intensity of impacts of multiple new dams in the Amazon basin on specific biological groups are potentially large, but still uncertain and need to be better understood.
2. It is known that river disruption and regulation by dams may affect sediment supplies, river channel migration, floodplain dynamics, and, as a major adverse consequence, are likely to decrease or even suppress ecological connectivity among populations of aquatic organisms and organisms dependent upon seasonally flooded environments.
3. This article complements our previous results by assessing the relationships between dams, our Dam Environmental Vulnerability Index (DEVI), and the biotic environments threatened by the effects of dams. Because of the cartographic representation of DEVI, it is a useful tool to compare the potential hydrophysical impacts of proposed dams in the Amazon basin with the spatial distribution of biological diversity. As the impact of Amazonian dams on the biota of both rivers and periodically flooded riparian environments is severe, DEVIs from different Amazonian tributary basins are contrasted with patterns of diversity and distribution of fish, flooded forest trees and bird species.
4. There is a consistent relationship between higher DEVI values and the patterns of higher species richness and endemism in all three biological groups. An assessment of vulnerability at the scale of tributary basins, the assessment of biodiversity patterns related to DEVI, and the analysis of teleconnections at basin scale, demonstrate that recent construction of dams is affecting the biota of the Amazon basin.
5. The evidence presented here predicts that, if currently planned dams are built without considering the balance between energy production and environmental conservation, their cumulative effects will increase drastically and represent a major threat to Amazonian biodiversity.

     

肉羊养殖效益分析及存在问题探讨

分析肉羊养殖的经济、社会效益,并就存在问题提出解决方法,进行技术探讨。     

布迪厄的语言观解析

布迪厄的语言观贯彻了其实践观，主要建立在反结构主义的基础上，试图说服语言学家跳出对符号系统的抽象分析，充分关注具体生动的语言实践过程，以避免用“虚幻的”规则代替语言本身；他认为语言不仅是表意的符号和沟通的手段，同时也是展现社会关系的媒介，特别是符号权力关系已经嵌入到语言符号体系中。尽管布迪厄对语言社会性的强调容易导致对语言本质的遮蔽，但是他的观点对拓宽语言学研究的视野、增强语言学研究的反思性具有不可忽视的参考价值。     

加强农村基层组织建设与社会稳定的若干思考

本文以当今中国农村改革发展稳定为背景,首先现实地阐释了当前加强农村基层组织建设、实现农村社会长期稳定,不仅是加速推进社会主义新农村建设的一项重大的“双基”工程,而且是构建社会主义农村和谐社会的必然诉求,更是提高党在农村的执政能力与水平的时代任务。然后,围绕创新农村基层组织建设的观念、加强乡镇公共组织建设、村级组织建设以及相应的执政能力建设、县乡(镇)村三级管理体制联动整合建设等内容,对如何加强我国农村基层组织建设、实现农村社会长期稳定,从理论与实证结合层面上进行了探讨。     

试论古村落旅游地开发的社会文化影响——以西递、宏村为例

古村落历史悠久,文化积淀深厚,且相对与外隔绝.随着现代化和全球化的发展,古村落作为独特的旅游资源被开发,其自身的社会文化所受影响是多方面的.本文在概括古村落旅游地旅游价值的基础上,分析了旅游开发对古村落旅游地社会文化造成的积极和消极影响,探讨了促进古村落旅游地开发和可持续发展的相关对策.