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The evolutionary effects of size-specific harvesting on animal populations : An experimental study using Daphnia magna StrausEdley, M. T. January 1987 (has links)
No description available.
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Assessment of allometry and length-at-age in the growth of fishesHernaÌndez, Antonio Valencia January 2003 (has links)
No description available.
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Production and mortality of early life stages of flatfishesEllis, Timothy Roberts January 1994 (has links)
Plankton sampling established the presence of a plaice spawning ground off the west coast of the Isle of Man in the Irish Sea. The total production of stage I plaice eggs from this spawning ground in 1993 was estimated at 7.6 x 101 • Theoretically this spawning ground could supply the local nurseries with plaice larvae. Spawning was most intense in March, before the peak in the plankton bloom in the Irish Sea. Predation on plaice eggs by clupeids was studied in March in an area of high plaice egg density to the east of the Isle of Man. Fish eggs formed the bulk of the stomach contents of sprat and herring due to the lack of alternative zooplankton food at this time of year. The later developmental stages of plaice eggs were more vulnerable to predation. This was thought to be due to the increase in pigmentation with embryonic development increasing the contrast between the egg and the water to predators that detect prey visually. Sprat and herring >80 mm showed a strong selection for plaice eggs over smaller pelagic fish eggs. However, the large eggs of plaice had a refuge in size from predation by sprat <80 mm. Smaller clupeids were feeding more actively than larger clupeids, as indicated by stomach fullness and the total number of fish eggs in stomachs. Stomach content data was combined with published biomass estimates and the daily instantaneous mortality rate of plaice eggs due to predation was estimated at 0.023 for sprat and 0.001 for herring. Sprat were therefore an important predator of plaice eggs in the Irish sea, whereas herring seemed of limited significance. Predation by fishes on O-group flatfishes was studied on a Scottish nursery ground by stomach content analysis. Fish predation was shown to be a significant source of mortality and I-group grey gurnards and gadoids were the major predators. Flounder suffered higher predation rates than plaice or dab due to the smaller size at settlement. Predation on plaice and dab was size-selective, concentrated on the smaller individuals. Smaller flatfishes were vulnerable to a greater size range and greater taxonomic range of predators. Predation by O-group cod on O-group dab was limited by the sizes of predator and prey. It was hypothesised that the times of recruitment of flatfishes and their predators to nurseries, and relative growth rates, would affect predation and hence mortality. The handling time of O-group flatfishes by O-group cod in laboratory experiments was positively related to flatfish size and negatively related to cod size. The handling time of plaice was longer than for dab of a similar size due to the difference in body shape. Profitability of flatfishes (wet weight gained per unit handling time) decreased monotonically with flatfish size over the range of prey and predator sizes used. It was therefore predicted that when O-group cod forage in the field the smallest O-group flatfishes would be the most profitable and would be behaviourally selected for. However, the selection of prey by cod was suggested to be determined by both behavioural and physical processes. There was evidence that behavioural selection of prey occurred at the ingestion stage of feeding. The current evidence for density-dependent processes in the juvenile stage of plaice was reviewed. Both the data in support of, and the processes thought to cause, density-dependent mortality in the juvenile phase were equivocal. It was hypothesised that density-dependent mortality occurs in the early egg stages of plaice and evidence, and the rationale for a potential predatory process resulting in such mortality, were presented.
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A organização política dos pescadores em uma comunidade ribeirinha no município de Tabatinga/AMOliveira, Maria Francenilda Gualberto de 10 December 2007 (has links)
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Previous issue date: 2007-12-10 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The political organization of fishermen configures itself from a series of changes in the fishing industry over the history of the region, the internal dynamics of the communities sobredeterminadas generated by the socio-economic and political environment of the region. From this understanding, the present study is to examine the purpose political organization of fishermen in the community Tauarú in the municipality of Tabatinga / Am.
The cut methodology considers the people who participate in studies as important actors in the formulation of new knowledge. The approach of stamp investigative and analytical, characterized as a case study, covering the combination of quantitative and qualitative data collected from the formal and informal representatives of fishermen in the community Tauarú. In this study, adopted is a set of tools and techniques mutually complementary, as application forms, semi-structured, formal and informal conversations, home visits, systematic observation and assistemática, registration fonográfico and photographs.
The discussion about the political organization, links to the configuration of social movements in the search for alternatives and strategies for answering the real demands of organized groups. Thus, the study indicates that the fishermen in the Amazon region, began to organize itself in the quest to defend the right to use and management of fish stocks. Therefore, the political organization of fishermen, engendered by changes in the fishery, where despite the difficulties, there is as a strategy to mobilize to have access to fishery resources and property and social services. / A organização política dos pescadores configura-se a partir um conjunto de mudanças ocorridas no setor da pesca ao longo da história da região, da dinâmica interna das comunidades sobredeterminadas geradas pelo contexto sócio-econômico e político da região. A partir dessa compreensão, o presente estudo tem como intuito analisar a organização política dos pescadores na comunidade Tauarú no município de Tabatinga/Am.
O recorte metodológico considera as populações que participam dos estudos como agentes importantes na formulação de novos saberes. A abordagem de cunho investigativo e analítico, caracterizou-se como um estudo de caso, abrangendo a associação de dados quantitativos e qualitativos coletados junto aos representantes formais e informais dos pescadores na comunidade Tauarú. Neste estudo, adotou-se um conjunto de instrumentos e técnicas complementares entre si, como aplicação de formulários, entrevistas semi-estruturadas, conversas formais e informais, visitas domiciliares, observação sistemática e assistemática, registro fonográfico e fotográfico.
A discussão acerca da organização política, articula-se com a configuração dos movimentos sociais na busca de alternativas e estratégias para o atendimento às reais demandas dos grupos organizados. Assim, o estudo indica que os pescadores na região Amazônica, passaram a organizar-se na busca de defender o direito de uso e gestão dos recursos pesqueiros.
Portanto, a organização política dos pescadores, engendrada pelas mudanças no contexto da pesca, em que pese às dificuldades, vislumbra-se como estratégia de mobilização tenham para o acesso aos recursos pesqueiros e aos bens e serviços sociais.
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Engraulis anchoita (Clupeiformes: Engraulidae) eggs and larvae in the Southeastern Brazilian Bight: new perspectives from a historical data set (1974 - 2010) / Engraulis anchoita (Clupeiformes: Engraulidae) ovos e larvas na Plataforma Continental Sudeste do Brasil: novas perspectivas a partir de um conjunto de dados históricos (1974 - 2010)Favero, Jana Menegassi Del 23 August 2016 (has links)
The main objective of this dissertation was to evaluate long-term fluctuations in the distribution and abundance of Engraulis anchoita eggs and larvae in the Southeastern Brazilian Bight (SBB). Engraulis anchoita is a fish species that is ecologically and economically important. We analyzed samples and abiotic data from eighteen oceanographic cruises conducted during austral late spring and early summer from 1974 to 2010. Two different stocks were detected in the SBB based on egg size, with the predominant stock in the area having smaller eggs than the stock in the region further south. Using indicative kriging, we identified occasional (e.g. Florianópolis - 27°S and off Santos Bay) and avoided (e.g. off São Sebastião Island and off Cananéia-Iguape Coastal System) spawning sites. Through zero-inflated models, spatial factors (different areas and the local depth) were related to the probability of sampling false zeros and temporal and oceanographic conditions (different years and temperature) with egg and larvae abundance. We also described faster and more accurate methodology to identify E. anchoita eggs, and compared the mesh-size efficiency to sample eggs and analyzed how egg size varied seasonally. Our results may support future studies and may assist a future fishery management of E. anchoita, a species not yet exploited in the SBB. / O principal objetivo dessa tese foi analisar as flutuações de longo-prazo na distribuição e abundância de ovos e larvas de Engraulias anchoita, uma espécie de peixe de importância econômica e ecológica, na Plataforma Continental Sudeste do Brasil (PCSE). Nós analisamos amostras e dados abióticos de dezoito cruzeiros oceanográficos realizados durante o fim da primavera e o começo do verão de 1974 a 2010. Dois estoques distintos foram identificados com base no tamanho dos ovos, um predominante e com menor tamanho e outro de maior tamanho ao sul da PCSE. Através de \"krigagem\" indicativa, foram identificadas áreas de desova ocasional (como ao norte de Florianópolis e a área ao largo da baía de Santos) e áreas em que a desova foi evitada (como em frente à Ilha de São Sebastião e ao Sistema Costeiro Cananéia-Iguape). Usando modelos inflacionados de zeros, os fatores espaciais (diferentes áreas e profundidades amostradas) foram relacionados com a probabilidade de se amostrar falso zero, enquanto os fatores temporais e oceanográficos (diferentes anos e temperatura) foram relacionados com a abundância de ovos e larvas. Apresentamos também uma metodologia mais rápida e mais eficiente para identificar os ovos de E. anchoita, comparamos as amostragens realizadas com duas malhagens diferentes e analisamos variações sazonais do tamanho dos ovos capturados. Assim, nossos resultados poderão auxiliar estudos futuros e também no manejo pesqueiro da espécie em questão, ainda não explorada comercialmente na área de estudo.
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Engraulis anchoita (Clupeiformes: Engraulidae) eggs and larvae in the Southeastern Brazilian Bight: new perspectives from a historical data set (1974 - 2010) / Engraulis anchoita (Clupeiformes: Engraulidae) ovos e larvas na Plataforma Continental Sudeste do Brasil: novas perspectivas a partir de um conjunto de dados históricos (1974 - 2010)Jana Menegassi Del Favero 23 August 2016 (has links)
The main objective of this dissertation was to evaluate long-term fluctuations in the distribution and abundance of Engraulis anchoita eggs and larvae in the Southeastern Brazilian Bight (SBB). Engraulis anchoita is a fish species that is ecologically and economically important. We analyzed samples and abiotic data from eighteen oceanographic cruises conducted during austral late spring and early summer from 1974 to 2010. Two different stocks were detected in the SBB based on egg size, with the predominant stock in the area having smaller eggs than the stock in the region further south. Using indicative kriging, we identified occasional (e.g. Florianópolis - 27°S and off Santos Bay) and avoided (e.g. off São Sebastião Island and off Cananéia-Iguape Coastal System) spawning sites. Through zero-inflated models, spatial factors (different areas and the local depth) were related to the probability of sampling false zeros and temporal and oceanographic conditions (different years and temperature) with egg and larvae abundance. We also described faster and more accurate methodology to identify E. anchoita eggs, and compared the mesh-size efficiency to sample eggs and analyzed how egg size varied seasonally. Our results may support future studies and may assist a future fishery management of E. anchoita, a species not yet exploited in the SBB. / O principal objetivo dessa tese foi analisar as flutuações de longo-prazo na distribuição e abundância de ovos e larvas de Engraulias anchoita, uma espécie de peixe de importância econômica e ecológica, na Plataforma Continental Sudeste do Brasil (PCSE). Nós analisamos amostras e dados abióticos de dezoito cruzeiros oceanográficos realizados durante o fim da primavera e o começo do verão de 1974 a 2010. Dois estoques distintos foram identificados com base no tamanho dos ovos, um predominante e com menor tamanho e outro de maior tamanho ao sul da PCSE. Através de \"krigagem\" indicativa, foram identificadas áreas de desova ocasional (como ao norte de Florianópolis e a área ao largo da baía de Santos) e áreas em que a desova foi evitada (como em frente à Ilha de São Sebastião e ao Sistema Costeiro Cananéia-Iguape). Usando modelos inflacionados de zeros, os fatores espaciais (diferentes áreas e profundidades amostradas) foram relacionados com a probabilidade de se amostrar falso zero, enquanto os fatores temporais e oceanográficos (diferentes anos e temperatura) foram relacionados com a abundância de ovos e larvas. Apresentamos também uma metodologia mais rápida e mais eficiente para identificar os ovos de E. anchoita, comparamos as amostragens realizadas com duas malhagens diferentes e analisamos variações sazonais do tamanho dos ovos capturados. Assim, nossos resultados poderão auxiliar estudos futuros e também no manejo pesqueiro da espécie em questão, ainda não explorada comercialmente na área de estudo.
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A Study on the Factors Contributing to the Formation of Coalitions in International Multilateral Environmental NegotiationsChung, Huey-shian 12 February 2009 (has links)
During negotiating process of drawing up global environmental conventions or protocols, negotiating parties to form different negotiation coalitions can be observed. However, few existing academic literature or studies have taken a systematic approach to explore the elements that contribute to the formation of these coalitions and to the changes of coalitions in the middle stage of negotiating process.
Through examining the negotiating process of several selected conferences for the establishment of global environmental treaties which are representative in nature and from different international environmental domains, this study is to find the core elements and sub-elements which contribute to the formation of negotiation coalitions.
This study shows that the composition of negotiation coalitions is dynamic. The timing of reorganizing the negotiating coalitions falls on the stage in which negotiation proceeds from principle issues to substantive ones. In other words, when the issues under negotiation begin to involve legally binding substantive commitments to State parties, the reorganization of negotiation coalitions emerges.
Furthermore, this study also finds that common elements do exist in the formation of negotiation coalitions. The core elements are ¡§the source of threat¡¨ and ¡§enhanceing the influence of a State¡¨; they are not affected by the change of negotiating issues. The other two sub-elements are: ¡§the same experience of participating in the same international organizations¡¨, the factor for forming negotiation coalitions during the stage of negotiation on principle issues, and ¡§domestic economic structure¡¨ during the stage of substantive issues negotiation for the formation of negotiation coalitions.
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Hållbar utveckling och CSR inom foderindustrin för hund och katt : Med fokus på det ekologiska perspektivetPierre, Johanna January 2014 (has links)
Pets like dogs and cats have a considerable importance for humans and research demonstrate a variety of positive economic and social effects in society due to our pet companions. The presences of pets are increasing on a global scale with correlation to economic development in low- and middle income countries. For example dogs have doubled in India over a five year period. The feed industry for dogs and cats is also the fastest growing sector in the food industry and certain pets have a significant animal protein intake which, depending on the choice of resources may provide a high ecological footprint. Examples of environmental effects with distribution and manufacturing of pet food are increased greenhouse gas emissions, waste, use of water and energy. Pet food producers have an important role to play in terms of corporate social responsibility (CSR) and sustainable development efforts, especially in their choice of sustainable protein resources as by-products from sustainable fisheries and livestock production. The purpose of this study was to investigate how pet food industry for dogs and cats generally working on sustainable development and CSR from primarily an ecological perspective in terms of ingredients, communication and production process. Ecological sustainability within pet food industry is more or less unexplored, and this study aims to create a broader understanding and interest for further studies in this field. This study was conducted using the multi method research including qualitative and quantitative methods on a global and national scale. The result is not possible to generalize, but some conclusions can be drawn. In relation to resources, by-products from food industry are a commonly used pet food content. But several companies are also marketing pet food containing “real meat, fish, poultry” with no or less byproducts. This seems to be a consumer driven trend. Indications that resources in pet food partly competes with human food system, give further considerations how to feed a growing human and pet population within planetary boundaries. All national and multinational cooperation’s in this study work more or less with CSR and sustainability from an ecological perspective. Generally there is visibly a weak relationship between companies’ sustainability activities and animal protein which should be a prerequisite in a production that is largely made of this resource, in relation to acute environmental degradation like climate change and depletion of fish stocks. Another conclusion is that corporate communication of environmental CSR and sustainability efforts on different pet food brand websites are almost non-existent. Finally, working with this study gave rise to many further questions and study subjects in relation to ecological sustainability within Pet food industry, not at least it´s relation to food industry and how this may effect global human meat consumption. / Sällskapsdjur i form av hund och katt har stor betydelse för människan och forskning påvisar en mängd positiva ekonomiska och sociala effekter som dessa ger oss. Förekomsten av sällskapsdjur visar en tydlig korrelation med ekonomisk utveckling och hundägandet har exempelvis fördubblats i Indien under en femårs period. Foderindustrin för hund och katt är samtidigt den snabbast växande sektorn inom livsmedelsindustrin. Hund och katt har som regel ett högt intag av animaliskt protein vilket beroende på resursval kan ge ett påtagligt ekologiskt fotavtryck. Själva foderproduktionen samt transporter ger också upphov till miljöpåverkan i form av t.ex. ökade utsläpp av växthusgaser, ökad vatten- och energianvändning samt avfall. Foderproducenterna har en viktig roll att fylla vad gäller sitt företagsansvar (CSR) samt arbete med hållbar utveckling ur ett ekologiskt perspektiv. Exempel på detta kan vara val av proteinresurser som biprodukter ifrån hållbart fiske och animalieproduktion. Syftet med denna studie var att undersöka hur foderindustrin för hund och katt generellt arbetar med hållbar utveckling samt CSR ur framförallt ett ekologiskt perspektiv vad gäller produktionsförfarande, kommunikation samt om foderingredienser kompletterar eller konkurrerar med livsmedelsingredienser. Området är relativt outforskat och studien syftar till att skapa en bredare förståelse samt intresse för djupare studier inom området. Undersökningen har utförts med hjälp av flermetodsforskning i form av kvalitativ samt kvantitativ metod på global och nationell nivå. Resultatet går inte att generalisera på foderindustrin globalt även om vissa slutsatser kan dras. I relation till resurser är förekomsten av biprodukter ifrån livsmedelsindustrin vanligt foderinnehåll men flera företag marknadsför också foder som innehåller ”riktigt kött, fisk, fågel” med frånvaro av eller lägre innehåll av biprodukter. Detta verkar vara en konsumentdriven trend. Både nationella samt multinationella företag i studien arbetar mer eller mindre med CSR och hållbarhet ur ett ekologiskt perspektiv. Generellt är det dock en svag koppling mellan miljöarbetet och animaliskt protein, vilket borde vara en förutsättning i en produktion som till stor del består av denna resurs i relation till akuta miljöproblem som klimatförändringen samt utfiskning. Ytterligare en slutsats är att företagens kommunikation av miljömässigt CSR- och hållbarhetsarbete på sina varumärkens hemsidor är närmast obefintlig. Slutligen väckte arbetetet med uppsatsen ett antal djupare frågeställningar samt ideér till fortsatta studier i relation till ekologisk hållbarhet inom foderindustrin. Inte minst avseende foderindustrins relation till livsmedelsindustrin och hur detta samband eventuellt kan påverka global köttkonsumtion. Foder för hund och katt konkurrerar dessutom till viss del med livsmedel vilket skapar utmaningen att föda både en ökande befolkning samt population av sällskapsdjur som skall livnära sig inom planetens gränser i framtiden.
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Livelihood assets and survival strategies in coastal communities in Kerala, IndiaDivakarannair, Nandakumar 30 November 2007 (has links)
Marine fish stocks are under serious threat of depletion due to increasing numbers of resource users with competing interests, resulting in degradation and the decline of fish catch. Using qualitative and quantitative techniques such as in-depth interviews, focus group discussions, household surveys and remote sensing and GIS, this study addresses: (1) the complex and inter-related nature of resource dependency, (2) the role of assets in determining survival strategies of households in artisanal fishing communities in Ponnani, India, (3) how asset degradation impacts resource-dependent households, (4) how households develop survival strategies, and (5) considers access to social, political, physical, human and financial assets. Information is organized using the Sustainable Livelihoods Framework (SLF) with modifications to suite the local complexities.
Results show that households - engaged in diverse activities, including fishing, fish processing/marketing/culture and daily labour - evolved property rights of natural resources over generations. The Pathemari cargo business’s limited knowledge of fisheries compared to artisanal fishers, and the government led modernization resulted in resource degradation. Therefore, artisanal fishers living in coastal wards threatened by intense erosion, abandoned traditional occupations in pursuit of livelihood security. Results from image analysis and derived thematic maps indicate increased erosion of 0.35 sq km shoreline coinciding with government development initiatives. To improve livelihood options, the results indicate that 50% surveyed accessed political assets such as fishers’ cooperatives and only 20% accessed financial assets such as government sponsored schemes and loans. In-depth interviews and focus group discussions revealed many limiting factors of access, specifically marginalization and lack of financial assets: only 6% surveyed could raise enough money to migrate. With changes in technology, from harvesting to processing, gender roles are being radically altered. Women are losing jobs and income. Politically, the study revealed that local participation helped governing bodies prioritize on housing, roads, water and sanitation.
Analysis of the information through the modified SLF suggests three strategies to enhance the asset base of coastal poor: strengthening grassroots organizations; transforming state relations; and developing new alternatives to conventional coastal development practice. Finally, the study suggests resource management policies to improve the households’ livelihood options and well-being.
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