Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades
Autor(a) principal: | |
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Data de Publicação: | 2018 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional do INPA |
Texto Completo: | https://repositorio.inpa.gov.br/handle/1/14660 |
Resumo: | Obligate river dolphins occur only in the rivers of Asia and South America, where they are increasingly subject to damaging pressures such as habitat degradation, food competition and entanglement in fishing gear as human populations expand. The Amazon basin hosts two, very different, dolphins—the boto or Amazon river dolphin (Inia geoffrensis) and the smaller tucuxi (Sotalia fluviatilis). Both species have wide geographical ranges and were once considered to be relatively abundant. Their IUCN Red List conservation status of Data Deficient (DD), due to limited information on threats, ecology, population numbers and trends, did not initially cause alarm. However, the development of dolphin hunting to provide fish bait at around the beginning of this millennium broadly coincided with the onset of a widespread perception that numbers of both species were in decline. Consequently, the need for population trend data to inform conservation advice and measures became urgent. This paper presents a 22-year time series of standardised surveys for both dolphins within the Mamirauá Reserve, Amazonas State, Brazil. Analysis of these data show that both species are in steep decline, with their populations halving every 10 years (botos) and 9 years (tucuxis) at current rates. These results are consistent with published, independent information on survival rates of botos in this area, which demonstrated a substantial drop in annual survival, commencing at around the year 2000. Mamirauá is a protected area, and is subject to fewer environmental pressures than elsewhere in the region, so there is no reason to suspect that the decline in dolphins within the Reserve is more pronounced than outside it. If South America’s freshwater cetaceans are to avoid following their Asian counterparts on the path to a perilous conservation status, effective conservation measures are required immediately. Enforcement of existing fishery laws would greatly assist in achieving this. © 2018 F. da Silva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
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Silva, Vera Maria Ferreira daCarvalho, Carlos Edwar Freitas deDias, Rodrigo L.Martin, Anthony Richard2020-04-24T17:00:00Z2020-04-24T17:00:00Z2018https://repositorio.inpa.gov.br/handle/1/1466010.1371/journal.pone.0191304Obligate river dolphins occur only in the rivers of Asia and South America, where they are increasingly subject to damaging pressures such as habitat degradation, food competition and entanglement in fishing gear as human populations expand. The Amazon basin hosts two, very different, dolphins—the boto or Amazon river dolphin (Inia geoffrensis) and the smaller tucuxi (Sotalia fluviatilis). Both species have wide geographical ranges and were once considered to be relatively abundant. Their IUCN Red List conservation status of Data Deficient (DD), due to limited information on threats, ecology, population numbers and trends, did not initially cause alarm. However, the development of dolphin hunting to provide fish bait at around the beginning of this millennium broadly coincided with the onset of a widespread perception that numbers of both species were in decline. Consequently, the need for population trend data to inform conservation advice and measures became urgent. This paper presents a 22-year time series of standardised surveys for both dolphins within the Mamirauá Reserve, Amazonas State, Brazil. Analysis of these data show that both species are in steep decline, with their populations halving every 10 years (botos) and 9 years (tucuxis) at current rates. These results are consistent with published, independent information on survival rates of botos in this area, which demonstrated a substantial drop in annual survival, commencing at around the year 2000. Mamirauá is a protected area, and is subject to fewer environmental pressures than elsewhere in the region, so there is no reason to suspect that the decline in dolphins within the Reserve is more pronounced than outside it. If South America’s freshwater cetaceans are to avoid following their Asian counterparts on the path to a perilous conservation status, effective conservation measures are required immediately. Enforcement of existing fishery laws would greatly assist in achieving this. © 2018 F. da Silva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Volume 13, Número 5Attribution-NonCommercial-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nc-nd/3.0/br/info:eu-repo/semantics/openAccessBrasilEcologyEnvironmentGeographyNonhumanPopulation DensityPopulation GrowthPressureSurvival RateToothed WhaleAnimalsCetaceaPopulation DynamicsStatistical ModelAnimalssBrasilCetaceaModels, StatisticalPopulation DynamicsBoth cetaceans in the Brazilian Amazon show sustained, profound population declines over two decadesinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlePLoS ONEengreponame:Repositório Institucional do INPAinstname:Instituto Nacional de Pesquisas da Amazônia (INPA)instacron:INPAORIGINALartigo-inpa.pdfapplication/pdf5968198https://repositorio.inpa.gov.br/bitstream/1/14660/1/artigo-inpa.pdf6c7a058b153c692053ed69769e909570MD51CC-LICENSElicense_rdfapplication/octet-stream914https://repositorio.inpa.gov.br/bitstream/1/14660/2/license_rdf4d2950bda3d176f570a9f8b328dfbbefMD521/146602020-07-14 09:19:15.169oai:repositorio:1/14660Repositório de PublicaçõesPUBhttps://repositorio.inpa.gov.br/oai/requestopendoar:2020-07-14T13:19:15Repositório Institucional do INPA - Instituto Nacional de Pesquisas da Amazônia (INPA)false |
dc.title.en.fl_str_mv |
Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades |
title |
Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades |
spellingShingle |
Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades Silva, Vera Maria Ferreira da Brasil Ecology Environment Geography Nonhuman Population Density Population Growth Pressure Survival Rate Toothed Whale Animals Cetacea Population Dynamics Statistical Model Animalss Brasil Cetacea Models, Statistical Population Dynamics |
title_short |
Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades |
title_full |
Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades |
title_fullStr |
Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades |
title_full_unstemmed |
Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades |
title_sort |
Both cetaceans in the Brazilian Amazon show sustained, profound population declines over two decades |
author |
Silva, Vera Maria Ferreira da |
author_facet |
Silva, Vera Maria Ferreira da Carvalho, Carlos Edwar Freitas de Dias, Rodrigo L. Martin, Anthony Richard |
author_role |
author |
author2 |
Carvalho, Carlos Edwar Freitas de Dias, Rodrigo L. Martin, Anthony Richard |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Silva, Vera Maria Ferreira da Carvalho, Carlos Edwar Freitas de Dias, Rodrigo L. Martin, Anthony Richard |
dc.subject.eng.fl_str_mv |
Brasil Ecology Environment Geography Nonhuman Population Density Population Growth Pressure Survival Rate Toothed Whale Animals Cetacea Population Dynamics Statistical Model Animalss Brasil Cetacea Models, Statistical Population Dynamics |
topic |
Brasil Ecology Environment Geography Nonhuman Population Density Population Growth Pressure Survival Rate Toothed Whale Animals Cetacea Population Dynamics Statistical Model Animalss Brasil Cetacea Models, Statistical Population Dynamics |
description |
Obligate river dolphins occur only in the rivers of Asia and South America, where they are increasingly subject to damaging pressures such as habitat degradation, food competition and entanglement in fishing gear as human populations expand. The Amazon basin hosts two, very different, dolphins—the boto or Amazon river dolphin (Inia geoffrensis) and the smaller tucuxi (Sotalia fluviatilis). Both species have wide geographical ranges and were once considered to be relatively abundant. Their IUCN Red List conservation status of Data Deficient (DD), due to limited information on threats, ecology, population numbers and trends, did not initially cause alarm. However, the development of dolphin hunting to provide fish bait at around the beginning of this millennium broadly coincided with the onset of a widespread perception that numbers of both species were in decline. Consequently, the need for population trend data to inform conservation advice and measures became urgent. This paper presents a 22-year time series of standardised surveys for both dolphins within the Mamirauá Reserve, Amazonas State, Brazil. Analysis of these data show that both species are in steep decline, with their populations halving every 10 years (botos) and 9 years (tucuxis) at current rates. These results are consistent with published, independent information on survival rates of botos in this area, which demonstrated a substantial drop in annual survival, commencing at around the year 2000. Mamirauá is a protected area, and is subject to fewer environmental pressures than elsewhere in the region, so there is no reason to suspect that the decline in dolphins within the Reserve is more pronounced than outside it. If South America’s freshwater cetaceans are to avoid following their Asian counterparts on the path to a perilous conservation status, effective conservation measures are required immediately. Enforcement of existing fishery laws would greatly assist in achieving this. © 2018 F. da Silva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
publishDate |
2018 |
dc.date.issued.fl_str_mv |
2018 |
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2020-04-24T17:00:00Z |
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2020-04-24T17:00:00Z |
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info:eu-repo/semantics/publishedVersion |
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dc.identifier.uri.fl_str_mv |
https://repositorio.inpa.gov.br/handle/1/14660 |
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10.1371/journal.pone.0191304 |
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https://repositorio.inpa.gov.br/handle/1/14660 |
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Volume 13, Número 5 |
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PLoS ONE |
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