968 resultados para Shark fishing
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Economic growth usually leads to a substantial increase in the demand for recreational fishing, and China is likely to follow this trend. Factors influencing this expansion in demand are identified. Recreational fishing is of major economic importance in higher income countries and indicators of its economic significance are given. Growing demand for recreational fishing results in intensified involvement of recreational fishers in conflicts about resource use. With increasing demand for recreational fishing, recreational fishers face growing competition with one another for limited fish stocks and with commercial fishers. Their concerns for environmental threats to fish stocks also intensify. Furthermore, some strategies of recreational fishers are increasingly criticised by conservationists. Governments, therefore, are put under pressure to adopt policies to address these conflicts. Some of the policy measures adopted to help sustain the fisheries and reduce conflict are outlined. These include limits on the catch and exclusive zones for recreational fishing. However, wild stocks of fish are likely to remain under mounting harvesting and other pressures. Therefore, we need to consider the role that aquaculture can play in overcoming these problems. The possible ways in which aquaculture can do this are outlined and discussed.
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Published eyewitness accounts and stories form Aboriginal Australians are used to provide an overview of the geographical extent and characteristics of cooperative fishing between Aboriginal Australians and dolphins in eastern Australia. These sources indicate that cooperative fishing was geographically widespread in eastern Australia, involved both bottlenose dolphins and orcas, and had a significance (emotional and Spiritual) to Aboriginal people beyond the acquisition of food. These fishing interactions represent both context and precedent for the economic and emotional-objectives of contemporary human-dolphin interactions such as dolphin provisioning. (C) 2002 International Society for Anthrozoology.
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The age of sex reversal of the venus tusk fish Choerodon venustus, caught by line fishing at various locations on the southern Great Barrier Reef, indicated that C. venustus is capable of modifying its life cycle in response to increased mortality. The evidence suggests Masthead Reef fish, which experience the highest mortality, underwent sex reversal at a smaller size and younger age than at the other sites. The largest female fish, sexually transitional fish and males were smaller at Masthead Reef than at the Swains Reefs or One Tree Reef at Masthead Reef. There was also considerable overlap in the size of males and females within the exploited populations indicating that sex reversal is not initiated at a particular length but may have a social cause. The sex ratio of fish was essentially the same for fish fully susceptible to line fishing in the Swains and Masthead samples. Circumstantial evidence suggested that the absence of large males in a population may initiate sex reversal, indicating the maintenance of a constant sex ratio may have a social basis. (C) 2002 The Fisheries Society of the British Isles.
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Examination of the lateral line canals in the Epaulette Shark reveals a much more differentiated sensory system than previously reported from any elasmobranch. Two main types of lateral line canals are found. In one type rounded patches of sensory epithelia are separated by elevations of the canal floor. The other type is a straight canal without restrictions and with an almost continuous sensory epithelium. In addition, we found epithelia (type A) with very long apical microvilli on the supporting cells. These microvilli reach beyond the stereovilli of the hair cells. Another type (B) of sensory epithelium has short microvilli on the supporting cells. In this latter type of epithelium the stereovilli of the hair cells are comparatively tall and reach out beyond the supporting cell microvilli. New hair cells are found widely in both types of sensory epithelia. These always occur as single cells, unlike those described in teleost lateral line canal sensory epithelia where new hair cells seem to form in pairs. Dying hair cells are also widespread, indicating a continuous turnover of hair cells.
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Reportamos atividades de pesca comerciais no complexo insular mais afastado da costa brasileira: Ilha da Trindade e Arquipélago Martin Vaz. As atividades foram estudadas através de embarques e entrevistas com os mestres e pescadores das embarcações durante uma expedição cientifica realizada entre fevereiro e abril de 2007. Quatro modalidades de atividades de pesca são realizadas na região, capturando ao menos sete espécies que possuem algum risco de extinção. O estabelecimento de normas específicas de restrição para atividades que pescam sobre os recifes das ilhas é uma alternativa para a conservação das espécies ameaçadas. O monitoramento das embarcações pode ocorrer via satélite através do programa nacional de rastreamento de embarcações pesqueiras (PREPS).
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New studies are giving ecologists some hope of controlling red lionfish, a voracious predator that has invaded the Atlantic.
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Copyright © 2014 Elsevier Science Ltd.
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Copyright © 2014 Elsevier Science Ltd.
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Tese de Doutoramento, Ciências do Mar (Ecologia Marinha)
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Tese de Doutoramento em Ciências do Mar, especialidade em Ecologia Marinha.
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Dissertação de Mestrado, Ciências Económicas e Empresariais, 8 de Janeiro de 2016, Universidade dos Açores.