Behavioral responses of Sotalia guianensis (Cetartiodactyla, Delphinidae) to boat approaches in northeast Brazil

ABSTRACT Boat engines increase the noise levels of the oceans, alter the acoustic environment of cetaceans and diminish their efficiency to echolocate. This study aims to determine if Guiana dolphins (Sotalia guianensis) are influenced by boat approaches. A land-based survey was conducted to record...

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Autores principales:	Marega-Imamura,Marcela, Carvalho,Gustavo Henrique de, Pendu,Yvonnick Le, Silva,Patricia Sousa da, Schiavetti,Alexandre
Lenguaje:	English
Publicado:	Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar 2018
Materias:	Sotalia guianensis Guiana dolphin behavior surfacing events dolphin-boat estuary Brazil
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2018000200268
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spelling	oai:scielo:S0718-560X20180002002682018-06-13Behavioral responses of Sotalia guianensis (Cetartiodactyla, Delphinidae) to boat approaches in northeast BrazilMarega-Imamura,MarcelaCarvalho,Gustavo Henrique dePendu,Yvonnick LeSilva,Patricia Sousa daSchiavetti,Alexandre Sotalia guianensis Guiana dolphin behavior surfacing events dolphin-boat estuary Brazil ABSTRACT Boat engines increase the noise levels of the oceans, alter the acoustic environment of cetaceans and diminish their efficiency to echolocate. This study aims to determine if Guiana dolphins (Sotalia guianensis) are influenced by boat approaches. A land-based survey was conducted to record behavioral responses and count surfacing events of Guiana dolphins during 293 observation sessions from February to November 2014 in Pontal Bay, Ilhéus, Brazil. Ninety-eight behavioral responses to boat approaches of 93 dolphin groups were classified as negative (interruption or alteration of activity) or neutral (no response). The dolphins presented a neutral response to 90% of boats without engine approaches, 48% negative responses to inboard motorboat approaches, and 76% negative responses to outboard motor boat approach. Resting groups demonstrated 14 negatives and four neutral responses. Groups engaged in forage-feed activity presented ten negative and seven neutral responses while traveling groups exhibited 14 negative and 36 neutral responses. The average rate of surfacing events was significantly superior (P < 0.001) in the absence of boats (1.83 ± 0.90 surfacing events ind-1 min-1) than in their presence (1.34 ± 0.92 surfacing events/individual/minute). Guiana dolphins are exposed to an increasing number of anthropic perturbations and the evaluation of its behavioral responses to approaching boats is the first step to comprehend the real impact of boat encounters. Our results may contribute to the development of management strategies in estuarine areas to increase the conservation of the Guiana dolphins.info:eu-repo/semantics/openAccessPontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del MarLatin american journal of aquatic research v.46 n.2 20182018-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2018000200268en10.3856/vol46-issue2-fulltext-3
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Sotalia guianensis Guiana dolphin behavior surfacing events dolphin-boat estuary Brazil
spellingShingle	Sotalia guianensis Guiana dolphin behavior surfacing events dolphin-boat estuary Brazil Marega-Imamura,Marcela Carvalho,Gustavo Henrique de Pendu,Yvonnick Le Silva,Patricia Sousa da Schiavetti,Alexandre Behavioral responses of Sotalia guianensis (Cetartiodactyla, Delphinidae) to boat approaches in northeast Brazil
description	ABSTRACT Boat engines increase the noise levels of the oceans, alter the acoustic environment of cetaceans and diminish their efficiency to echolocate. This study aims to determine if Guiana dolphins (Sotalia guianensis) are influenced by boat approaches. A land-based survey was conducted to record behavioral responses and count surfacing events of Guiana dolphins during 293 observation sessions from February to November 2014 in Pontal Bay, Ilhéus, Brazil. Ninety-eight behavioral responses to boat approaches of 93 dolphin groups were classified as negative (interruption or alteration of activity) or neutral (no response). The dolphins presented a neutral response to 90% of boats without engine approaches, 48% negative responses to inboard motorboat approaches, and 76% negative responses to outboard motor boat approach. Resting groups demonstrated 14 negatives and four neutral responses. Groups engaged in forage-feed activity presented ten negative and seven neutral responses while traveling groups exhibited 14 negative and 36 neutral responses. The average rate of surfacing events was significantly superior (P < 0.001) in the absence of boats (1.83 ± 0.90 surfacing events ind-1 min-1) than in their presence (1.34 ± 0.92 surfacing events/individual/minute). Guiana dolphins are exposed to an increasing number of anthropic perturbations and the evaluation of its behavioral responses to approaching boats is the first step to comprehend the real impact of boat encounters. Our results may contribute to the development of management strategies in estuarine areas to increase the conservation of the Guiana dolphins.
author	Marega-Imamura,Marcela Carvalho,Gustavo Henrique de Pendu,Yvonnick Le Silva,Patricia Sousa da Schiavetti,Alexandre
author_facet	Marega-Imamura,Marcela Carvalho,Gustavo Henrique de Pendu,Yvonnick Le Silva,Patricia Sousa da Schiavetti,Alexandre
author_sort	Marega-Imamura,Marcela
title	Behavioral responses of Sotalia guianensis (Cetartiodactyla, Delphinidae) to boat approaches in northeast Brazil
title_short	Behavioral responses of Sotalia guianensis (Cetartiodactyla, Delphinidae) to boat approaches in northeast Brazil
title_full	Behavioral responses of Sotalia guianensis (Cetartiodactyla, Delphinidae) to boat approaches in northeast Brazil
title_fullStr	Behavioral responses of Sotalia guianensis (Cetartiodactyla, Delphinidae) to boat approaches in northeast Brazil
title_full_unstemmed	Behavioral responses of Sotalia guianensis (Cetartiodactyla, Delphinidae) to boat approaches in northeast Brazil
title_sort	behavioral responses of sotalia guianensis (cetartiodactyla, delphinidae) to boat approaches in northeast brazil
publisher	Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar
publishDate	2018
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2018000200268
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_version_	1714205197697286144

Behavioral responses of Sotalia guianensis (Cetartiodactyla, Delphinidae) to boat approaches in northeast Brazil

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