Taxonomia, biologia reprodutiva e dieta da Raia Borboleta, Gymnura micrura (Myliobatiformes: Elasmobranchii)
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2010-10-15
Autores
Yokota, Leandro [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo do presente estudo foi estudar a estrutura populacional, biologia reprodutiva e dieta dos exemplares identificados como Gymnura micrura capturados na região de Caiçara do Norte (RN), além de definir sua correta identidade taxonômica através de uma comparação com exemplares provenientes de outras localidades dentro de sua suposta área de ocorrência no Atlântico Oeste. A revisão da família Gymnuridae no Brasil é realizada. Os exemplares foram obtidos através do acompanhamento da pesca artesanal na região de Caiçara do Norte (RN) durante o período de agosto de 2007 a julho de 2008. Visitas a coleções foram realizadas para análise do material comparativo. A espécie em questão trata-se realmente de Gymnura micrura (BLOCH & SCHNEIDER, 1801), ocorrendo da costa norte dos Estados Unidos ao sul do Brasil (Paraná). No Brasil ocorrem dois representantes da família Gymnuridae: Gymnura micrura e Gymnura altavela. A terceira espécie que ocorreria no Brasil, G. hirundo, é proposta como um sinônimo júnior de G. altavela. São apresentadas evidências contra a validade do gênero Aetoplatea, sendo que a família seria representada apenas por um gênero (Gymnura). Na população estudada indivíduos maiores tendem a ocupar águas mais profundas e entre os jovens parece existir uma leve tendência à segregação sexual por profundidade, com os machos ocupando águas ligeiramente mais profundas. O tamanho de primeira maturação dos machos e fêmeas foi estimado em 275 e 410 mm de largura do disco (LD) respectivamente, enquanto o tamanho de nascimento foi estimado entre 135 e 175 mm LD. A fecundidade uterina foi estimada em 3,8±1,3 embriões, e foi significativamente correlacionada com a LD das fêmeas. É proposta uma reprodução contínua ao longo do ano sem qualquer sincronismo em nível populacional. A dieta foi constituída basicamente de teleósteos...
The purpose of the present thesis was to study the population structure, reproductive biology and diet of the specimens identified as Gymnura micrura from Caiçara do Norte-RN (Northeast Brazil), and to define their correct taxonomic identity by comparing them with specimens from other regions within their supposed area of occurrence at the Western Atlantic. A review of the family Gymnuridae in Brazil was carried out. The specimens were obtained by monitoring the artisanal fisheries in the region of Caiçara do Norte (RN) during the period from August 2007 to July 2008. Visits to scientific collections were made for analysis of comparative material. The species studied was confirmed to be Gymnura micrura (BLOCH & SCHNEIDER, 1801), which occurs from the northern coast of the United States to southern Brazil (Paraná State). In Brazil there are two species of the family Gymnuridae: Gymnura micrura and Gymnura altavela. The third species known as occurring in Brazil, G. hirundo, is proposed as a junior-synonym of G. altavela. Evidence against the validity of genus Aetoplatea is presented, so the family Gymnuridae should be represented by only one genus (Gymnura). In the population studied larger individuals tend to occupy deeper waters and among the young individuals there seems to exist a slight tendency for sexual segregation by depth, with males occupying slightly deeper waters. Mean sizes at maturity were 275 mm disc width (DW) in males and 410 mm DW in females. Size at birth was 135 – 175 mm DW. The uterine fecundity was assessed in 3.8±1.3 embryos, and was significantly correlated with female DW. It is proposed that in the study area breeding occurs throughout the year with no population synchronism. The diet consisted mainly of teleosts (IA = 99.5 %), with the predominance of one species (Pomadasys corvinaeformis). The graphical ecological analysis characterizes... (Complete abstract click electronic access below)
The purpose of the present thesis was to study the population structure, reproductive biology and diet of the specimens identified as Gymnura micrura from Caiçara do Norte-RN (Northeast Brazil), and to define their correct taxonomic identity by comparing them with specimens from other regions within their supposed area of occurrence at the Western Atlantic. A review of the family Gymnuridae in Brazil was carried out. The specimens were obtained by monitoring the artisanal fisheries in the region of Caiçara do Norte (RN) during the period from August 2007 to July 2008. Visits to scientific collections were made for analysis of comparative material. The species studied was confirmed to be Gymnura micrura (BLOCH & SCHNEIDER, 1801), which occurs from the northern coast of the United States to southern Brazil (Paraná State). In Brazil there are two species of the family Gymnuridae: Gymnura micrura and Gymnura altavela. The third species known as occurring in Brazil, G. hirundo, is proposed as a junior-synonym of G. altavela. Evidence against the validity of genus Aetoplatea is presented, so the family Gymnuridae should be represented by only one genus (Gymnura). In the population studied larger individuals tend to occupy deeper waters and among the young individuals there seems to exist a slight tendency for sexual segregation by depth, with males occupying slightly deeper waters. Mean sizes at maturity were 275 mm disc width (DW) in males and 410 mm DW in females. Size at birth was 135 – 175 mm DW. The uterine fecundity was assessed in 3.8±1.3 embryos, and was significantly correlated with female DW. It is proposed that in the study area breeding occurs throughout the year with no population synchronism. The diet consisted mainly of teleosts (IA = 99.5 %), with the predominance of one species (Pomadasys corvinaeformis). The graphical ecological analysis characterizes... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Peixe, Reprodução, Nutrição, Conservação, Brasil, Nordeste, Peixes cartilaginosos, Gymnuridae
Como citar
YOKOTA, Leandro. Taxonomia, biologia reprodutiva e dieta da Raia Borboleta, Gymnura micrura (Myliobatiformes: Elasmobranchii). 2010. 126 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2010.