Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae) in Ilha Grande Bay, Rio de Janeiro, southeastern Brazil

Cetaceans present a group structure of great complexity and display a wide behavioral plasticity. Many efforts have been made to understand the group structures of the various species, however, this type of information is still lacking for some species. Therefore, our objectives were to 1) character...

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Autores principales:	Tardin,Rodrigo, Galvão,Carine, Espécie,Mariana, Simão,Sheila
Lenguaje:	English
Publicado:	Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar 2013
Materias:	Sotalia guianensis Guiana dolphin group structure Ilha Grande Bay southeastern Brazil
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2013000200010
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spelling	oai:scielo:S0718-560X20130002000102013-08-13Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae) in Ilha Grande Bay, Rio de Janeiro, southeastern BrazilTardin,RodrigoGalvão,CarineEspécie,MarianaSimão,Sheila Sotalia guianensis Guiana dolphin group structure Ilha Grande Bay southeastern Brazil Cetaceans present a group structure of great complexity and display a wide behavioral plasticity. Many efforts have been made to understand the group structures of the various species, however, this type of information is still lacking for some species. Therefore, our objectives were to 1) characterize the structure of the Sotalia guianensis groups in Ilha Grande Bay, Rio de Janeiro, Brazil, and 2) investigate how both behavior and season influence the group structure of this population. This species is considered "data deficient" by the IUCN. We conducted 28 boat trips using group focal procedures, and a total of 1,314 groups were observed. Of these groups, 1,268 (94.4%) contained calves, the largest percentage ever reported for the species. Groups with calves were larger than those without them, suggesting a strategy to protect these individuals with underdeveloped physiology. The mean group sizes reached 17.6 ± 18.3 individuals. Within these groups, we observed that both behavior (H = 112.5, d.f. = 2, P < 0.05) and season (number of simulations: 10,000; sample size of fall-winter = 544; sample size of spring-summer = 684; P < 0.05), demonstrated a statistically significant influence. The most common degree of cohesion was mixed, and cohesion also varied with behavior (χ2 = 10.1, P < 0.05) and season (χ2 = 31.0, P < 0.05). This paper contributes towards understanding the highly variable nature of S. guianensis group dynamics. These data may be important in understanding the structure of groups in a site that is being increasingly impacted by different human activities. Moreover, this area contains the largest aggregation ever observed for this species and may therefore represent an important source of genetic diversity for the species as a whole.info:eu-repo/semantics/openAccessPontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del MarLatin american journal of aquatic research v.41 n.2 20132013-04-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2013000200010en10.3856/vol41-issue2-fulltext-10
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Sotalia guianensis Guiana dolphin group structure Ilha Grande Bay southeastern Brazil
spellingShingle	Sotalia guianensis Guiana dolphin group structure Ilha Grande Bay southeastern Brazil Tardin,Rodrigo Galvão,Carine Espécie,Mariana Simão,Sheila Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae) in Ilha Grande Bay, Rio de Janeiro, southeastern Brazil
description	Cetaceans present a group structure of great complexity and display a wide behavioral plasticity. Many efforts have been made to understand the group structures of the various species, however, this type of information is still lacking for some species. Therefore, our objectives were to 1) characterize the structure of the Sotalia guianensis groups in Ilha Grande Bay, Rio de Janeiro, Brazil, and 2) investigate how both behavior and season influence the group structure of this population. This species is considered "data deficient" by the IUCN. We conducted 28 boat trips using group focal procedures, and a total of 1,314 groups were observed. Of these groups, 1,268 (94.4%) contained calves, the largest percentage ever reported for the species. Groups with calves were larger than those without them, suggesting a strategy to protect these individuals with underdeveloped physiology. The mean group sizes reached 17.6 ± 18.3 individuals. Within these groups, we observed that both behavior (H = 112.5, d.f. = 2, P < 0.05) and season (number of simulations: 10,000; sample size of fall-winter = 544; sample size of spring-summer = 684; P < 0.05), demonstrated a statistically significant influence. The most common degree of cohesion was mixed, and cohesion also varied with behavior (χ2 = 10.1, P < 0.05) and season (χ2 = 31.0, P < 0.05). This paper contributes towards understanding the highly variable nature of S. guianensis group dynamics. These data may be important in understanding the structure of groups in a site that is being increasingly impacted by different human activities. Moreover, this area contains the largest aggregation ever observed for this species and may therefore represent an important source of genetic diversity for the species as a whole.
author	Tardin,Rodrigo Galvão,Carine Espécie,Mariana Simão,Sheila
author_facet	Tardin,Rodrigo Galvão,Carine Espécie,Mariana Simão,Sheila
author_sort	Tardin,Rodrigo
title	Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae) in Ilha Grande Bay, Rio de Janeiro, southeastern Brazil
title_short	Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae) in Ilha Grande Bay, Rio de Janeiro, southeastern Brazil
title_full	Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae) in Ilha Grande Bay, Rio de Janeiro, southeastern Brazil
title_fullStr	Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae) in Ilha Grande Bay, Rio de Janeiro, southeastern Brazil
title_full_unstemmed	Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae) in Ilha Grande Bay, Rio de Janeiro, southeastern Brazil
title_sort	group structure of guiana dolphins, sotalia guianensis (cetacea, delphinidae) in ilha grande bay, rio de janeiro, southeastern brazil
publisher	Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar
publishDate	2013
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2013000200010
work_keys_str_mv	AT tardinrodrigo groupstructureofguianadolphinssotaliaguianensiscetaceadelphinidaeinilhagrandebayriodejaneirosoutheasternbrazil AT galvaocarine groupstructureofguianadolphinssotaliaguianensiscetaceadelphinidaeinilhagrandebayriodejaneirosoutheasternbrazil AT especiemariana groupstructureofguianadolphinssotaliaguianensiscetaceadelphinidaeinilhagrandebayriodejaneirosoutheasternbrazil AT simaosheila groupstructureofguianadolphinssotaliaguianensiscetaceadelphinidaeinilhagrandebayriodejaneirosoutheasternbrazil
_version_	1714205107864731648

Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae) in Ilha Grande Bay, Rio de Janeiro, southeastern Brazil

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