Biologia reprodutiva de toninha, Pontoporia blainvillei (Gervais & D'Orbigny, 1844) (Mammalia Cetacea), no litoral sul de São Paulo e norte do Paraná
Carregando...
Arquivos
Data
2011-08-12
Autores
Silva, Débora Freitas da [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A biologia reprodutiva de toninhas, Pontoporia blainvillei, capturadas acidentalmente em redes de pesca entre abril de 2005 e agosto de 2007 do sul do estado de São Paulo (24º24’S, 46°57’W) ao norte do Paraná (25º22’S, 48º09’W) foi estudada. Os testículos de 57 machos e os ovários de 35 fêmeas foram analisados macro e microscopicamente para determinação da maturidade sexual. As presenças de leite nas glândulas mamárias e de feto no útero foram avaliadas para determinação de lactação e de prenhez das fêmeas, respectivamente. A proporção apresentada entre machos e fêmeas capturados acidentalmente foi de 1,6:1. As idades de 86 indivíduos foram estimadas a partir da contagem do número de grupos de linhas de crescimento presentes nas camadas de dentina e de cemento dos dentes. As idades variaram de zero a 18 anos para machos e de zero a 12 anos para fêmeas. A mediana das idades foi de um ano e 75 indivíduos (87,2%) tinham até três anos de idade. A análise histológica revelou que 21 dos 57 machos analisados (36,8%) estavam sexualmente maduros. Os testículos apresentaram simetria lateral e baixo peso testicular relativo em relação ao peso corporal, sendo em média de 0,031% em machos maduros sexualmente. O peso testicular combinado (soma dos pesos de ambos os testículos), a largura testicular média, o comprimento testicular médio e o índice de maturidade testicular (razão entre o peso e o comprimento dos testículos) se demonstraram como potenciais ferramentas macroscópicas para auxiliar na identificação de indivíduos maduros, mas a análise histológica ainda é necessária para confirmação dos estágios de maturidade em machos
The reproductive biology of franciscana dolphins, Pontoporia blainvillei, incidentally caught by gillnets between 2005 and 2007 from southern São Paulo (24°24’S, 46°57’W) to northern Paraná (25º22’S, 48°09’W) States was studied. The testes of 57 males and the ovaries of 35 females were macroscopically and microscopically analyzed to determine the sexual maturity. The presence of milk in the mammary glands and of fetus in the uterus was evaluated to determine lactating and pregnant females, respectively. The ratio between males and females incidentally caught was 1.6:1. The age (n=86) was estimated through growth layer groups in dentine and cementum using longitudinal sections of teeth. The ages ranged from zero to 18 years for males and from zero to 12 years for females. The median of age was one year and 75 individuals (87.2%) were three years old or less when captured. Histological analysis revealed that 21 of the 57 males analyzed (36.8%) were sexually mature. The testes showed lateral symmetry and low testicular weight relative to body weight, with an average of 0.031% in sexually mature males. The combined testicular weight (sum of weights of both testes), the average testicular width, the average testicular length and testicular maturity index (ratio of testicular weight per testicular length) were considered as potential macroscopic tools to classify mature individuals, but histological confirmation is still required to confirm the sexual maturity condition
The reproductive biology of franciscana dolphins, Pontoporia blainvillei, incidentally caught by gillnets between 2005 and 2007 from southern São Paulo (24°24’S, 46°57’W) to northern Paraná (25º22’S, 48°09’W) States was studied. The testes of 57 males and the ovaries of 35 females were macroscopically and microscopically analyzed to determine the sexual maturity. The presence of milk in the mammary glands and of fetus in the uterus was evaluated to determine lactating and pregnant females, respectively. The ratio between males and females incidentally caught was 1.6:1. The age (n=86) was estimated through growth layer groups in dentine and cementum using longitudinal sections of teeth. The ages ranged from zero to 18 years for males and from zero to 12 years for females. The median of age was one year and 75 individuals (87.2%) were three years old or less when captured. Histological analysis revealed that 21 of the 57 males analyzed (36.8%) were sexually mature. The testes showed lateral symmetry and low testicular weight relative to body weight, with an average of 0.031% in sexually mature males. The combined testicular weight (sum of weights of both testes), the average testicular width, the average testicular length and testicular maturity index (ratio of testicular weight per testicular length) were considered as potential macroscopic tools to classify mature individuals, but histological confirmation is still required to confirm the sexual maturity condition
Descrição
Palavras-chave
Cetaceo - Reprodução, Biologia costeira, Maturidade sexual, Franciscana dolphin - Reproductive biology
Como citar
SILVA, Débora Freitas da. Biologia reprodutiva de toninha, Pontoporia blainvillei (Gervais & D'Orbigny, 1844) (Mammalia Cetacea), no litoral sul de São Paulo e norte do Paraná. 2011. 130 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2011.