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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Caracteriza??o da captura incidental de tartarugas marinhas pela pesca de espinhel pel?gico no Nordeste do Brasil

Coluchi, Rodrigo 08 December 2006 (has links)
Made available in DSpace on 2014-12-17T14:02:03Z (GMT). No. of bitstreams: 1 RodrigoC.pdf: 1253605 bytes, checksum: 901bba0a33ba9a917533656bc7e7c6b0 (MD5) Previous issue date: 2006-12-08 / The marine turtles biological characteristics and the impact they have been suffering in consequence of human activities have caused in the last decades the decrease of populations to unsustainable levels. All four of the species described in this paper are registered as endangered in a list by IUCN: Caretta caretta, Lepidochelys olivacea, Chelonia mydas, Dermochelys coriacea. The main causes of such impact include several fishing activities, mostly the surface longline. This paper discusses the monitoring of two foreigner longline fleet along the North East Brazilian coast between October of 2004 and September of 2005. Both operated in the West South Atlantic, one using the Chinese technique and the other the American. The American method s target species is the swordfish (Xiphias gladius), and it is characterized by using squid as bait, J 9/0 offset 5? hook, light sticks and night soaking. It also operates in shallower waters than the Chinese method. The source of information about the efforts and the catches came from onboard observers and were used to calculate the catching rate of turtles over 1000 hooks (CPUE). The American equipment caught more turtles (CPUE = 0,059; N= 103), mainly D. coriacea, while the Chinese longline caught mainly the L. olivacea and presented a CPUE= 0,018 (N= 89). The hooks were most frequently found attached to the mouth of C. caretta, C. mydas, and L. olivacea. The D. coriacea were most frequently caught by hooks externally attached to different parts of their body. There was no significant difference between the hook type catching and most turtles were still alive when released. The results suggest a greater potential of turtle catching by the American method. Besides the statistic tests have showed less interaction between the Chinese equipment and marine turtles, the catches of this fishing technique could have been underestimated due to miscommunication between the onboard observer and the vessel s crew plus the retrieve of the longline during night time / As caracter?sticas biol?gicas das tartarugas marinhas em conjunto com as diversas perturba??es antr?pica sofridas ao longo do tempo t?m reduzido v?rias popula??es para n?veis quase invi?veis de se manterem, atualmente, as quatro esp?cies registradas nesse trabalho s?o citadas na lista de fauna amea?ada da Uni?o Internacional para Conserva??o da Natureza - IUCN (Caretta caretta, Chelonia mydas, Dermochelys coriacea e Lepidochelys olivacea). Entre os principais riscos que est?o sujeitas as tartarugas marinhas podemos citar as atividades pesqueiras de maneira geral e em especial o espinhel pel?gico de superf?cie. O presente estudo apresenta o monitoramento realizado junto a duas frotas estrangeiras de espinhel de superf?cie sediadas no nordeste do Brasil, ente outubro de 2004 e setembro de 2005. Ambas atuaram no Atl?ntico Sul Ocidental, sendo que o espinhel chin?s teve como objetivo a captura de atuns (Thunnus spp), utilizando peixe como isca, anzol tipo tunna hook e imers?o do petrecho de pesca durante o dia. A esp?cie alvo do petrecho chamado de americano foi o espadarte (Xiphias gladius), que se caracterizou por utilizar lula como isca, anzol tipo J 9/0 offset 5?, atrator luminoso, imers?o noturna e mais rasa do que o chin?s. As informa??es a respeito do esfor?o e das capturas foram provenientes de observadores de bordo e utilizadas para calcular os ?ndices de capturas de tartarugas por 1000 anz?is (CPUE). O petrecho americano capturou mais tartarugas (CPUE= 0,059, N= 113) e foi mais representado por D. coriacea, enquanto o espinhel chin?s apresentou CPUE = 0,018 (N= 89) e L. olivacea como a esp?cie mais numerosa. O local mais comum de insers?o do anzol em C. caretta, C. mydas e L. olivacea foi a boca. As D.coriacea foram mais capturadas quando o anzol se prendeu externamente. N?o houve diferen?a significativa das capturas conforme o tipo de anzol, e os indiv?duos liberados vivos predominaram. Os resultados encontrados corroboram com o maior potencial de capturas de tartarugas atribu?do ?s caracter?sticas do petrecho que tem como alvo os espadartes. No entanto, testes estat?sticos demonstraram que, apesar do petrecho voltado ? captura de atuns interagir menos com tartarugas marinhas, as capturas na pescaria chinesa foram subestimadas devido ? dificuldade de comunica??o do observador com a tripula??o e recolhimento do espinhel durante a noite

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