The impact of incidental kills by gill nets on the franciscana dolphin (pontoporia blainvillei) in southern Brazil
The franciscana dolphin, Pontoporia blainvillei, is endemic to the western South Atlantic Ocean. Its distribution is restricted to waters up to 30 m depth, making it vulnerable to human influence. In southern Brazil the artisanal gillnet fisheries have increased since the early 1980s, and entangleme...
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ftunivfurg:oai:repositorio.furg.br:1/981 2023-11-12T04:26:13+01:00 The impact of incidental kills by gill nets on the franciscana dolphin (pontoporia blainvillei) in southern Brazil Kinas, Paul Gerhard 2002 application/pdf http://repositorio.furg.br/handle/1/981 eng eng KINAS, Paul G. The impact of incidental kills by gill nets on the franciscana dolphin (Pontoporia blainvillei) in southern Brazil. Bulletin of Marine Science, v. 70, n. 2, p. 409-421, 2002. Disponível em: <http://docserver.ingentaconnect.com/deliver/connect/umrsmas/00074977/v70n2/s5.pdf?expires=1314119137&id=64085433&titleid=10983&accname=Guest+User&checksum=E8C14F00D3866E5AB356941001B73722>. Acesso em: 24 ago. 2011. 0007-4977 http://repositorio.furg.br/handle/1/981 restrict access article 2002 ftunivfurg 2023-10-24T21:01:31Z The franciscana dolphin, Pontoporia blainvillei, is endemic to the western South Atlantic Ocean. Its distribution is restricted to waters up to 30 m depth, making it vulnerable to human influence. In southern Brazil the artisanal gillnet fisheries have increased since the early 1980s, and entanglement mortality of franciscanas has become a source for concern. Strandings have been documented for about 20 yrs, but the impact of incidental captures has remained unknown. In the 1990s numbers of franciscanas incidentally killed by the artisanal gillnet fleet, population size, and the intrinsic growth rate were estimated. I integrated all available information into a population model in order to quantify the impact of incidental kills. The statistical analysis was conducted within a Bayesian framework to maintain coherence while current biological knowledge was weighted with observational data. My analysis indicated a 99% probability that the population is decreasing. For analysis of future impact of the incidental kill the population was defined as being at ‘quasi collapse’ when it reached 10% of its current size, and the probability of quasi collapse within 30 yrs was calculated under alternative scenarios. Results indicate that current levels of entanglement mortality cannot be sustained and that protective measures are needed. Article in Journal/Newspaper South Atlantic Ocean RI FURG (Repositório da Universidade Federal do Rio Grande) |
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Open Polar |
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RI FURG (Repositório da Universidade Federal do Rio Grande) |
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ftunivfurg |
language |
English |
description |
The franciscana dolphin, Pontoporia blainvillei, is endemic to the western South Atlantic Ocean. Its distribution is restricted to waters up to 30 m depth, making it vulnerable to human influence. In southern Brazil the artisanal gillnet fisheries have increased since the early 1980s, and entanglement mortality of franciscanas has become a source for concern. Strandings have been documented for about 20 yrs, but the impact of incidental captures has remained unknown. In the 1990s numbers of franciscanas incidentally killed by the artisanal gillnet fleet, population size, and the intrinsic growth rate were estimated. I integrated all available information into a population model in order to quantify the impact of incidental kills. The statistical analysis was conducted within a Bayesian framework to maintain coherence while current biological knowledge was weighted with observational data. My analysis indicated a 99% probability that the population is decreasing. For analysis of future impact of the incidental kill the population was defined as being at ‘quasi collapse’ when it reached 10% of its current size, and the probability of quasi collapse within 30 yrs was calculated under alternative scenarios. Results indicate that current levels of entanglement mortality cannot be sustained and that protective measures are needed. |
format |
Article in Journal/Newspaper |
author |
Kinas, Paul Gerhard |
spellingShingle |
Kinas, Paul Gerhard The impact of incidental kills by gill nets on the franciscana dolphin (pontoporia blainvillei) in southern Brazil |
author_facet |
Kinas, Paul Gerhard |
author_sort |
Kinas, Paul Gerhard |
title |
The impact of incidental kills by gill nets on the franciscana dolphin (pontoporia blainvillei) in southern Brazil |
title_short |
The impact of incidental kills by gill nets on the franciscana dolphin (pontoporia blainvillei) in southern Brazil |
title_full |
The impact of incidental kills by gill nets on the franciscana dolphin (pontoporia blainvillei) in southern Brazil |
title_fullStr |
The impact of incidental kills by gill nets on the franciscana dolphin (pontoporia blainvillei) in southern Brazil |
title_full_unstemmed |
The impact of incidental kills by gill nets on the franciscana dolphin (pontoporia blainvillei) in southern Brazil |
title_sort |
impact of incidental kills by gill nets on the franciscana dolphin (pontoporia blainvillei) in southern brazil |
publishDate |
2002 |
url |
http://repositorio.furg.br/handle/1/981 |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_relation |
KINAS, Paul G. The impact of incidental kills by gill nets on the franciscana dolphin (Pontoporia blainvillei) in southern Brazil. Bulletin of Marine Science, v. 70, n. 2, p. 409-421, 2002. Disponível em: <http://docserver.ingentaconnect.com/deliver/connect/umrsmas/00074977/v70n2/s5.pdf?expires=1314119137&id=64085433&titleid=10983&accname=Guest+User&checksum=E8C14F00D3866E5AB356941001B73722>. Acesso em: 24 ago. 2011. 0007-4977 http://repositorio.furg.br/handle/1/981 |
op_rights |
restrict access |
_version_ |
1782340278760243200 |