Ecologia e estrutura populacional do camarão Litopenaeus schmitti (Burkenroad, 1936) (Dendrobranchiata: Penaeoidea) na região de Cananéia, litoral sul do estado de São Paulo

• Autor(a) principal: Barioto, João Gabriel [UNESP]
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/150967
• topic: Seleção por habitat; Decapoda; Berçário; Penaeidae

The present study was divided into two chapters that aimed to verify the spatiotemporal abundance of juveniles and adults, analyzing how the variation of the environmental factors (salinity, water temperature, rainfall, phi, organic matter) affect the distribution patterns and describe the population dynamics of Litopenaeus schmitti in Cananéia, south coast of the São Paulo state, Brazil. With a shrimp boat the shrimp and environmental factors were sampled monthly from July 2012 to May 2014, covering both the marine and estuarine environment. In the laboratory, shrimps were separated according to sex, measured on carapace length (CC) and classified for gonadal development stage. Growth and longevity were estimated from the von Bertalanffy equation and the sex ratio was tested by applying the Binomial test. A total of 1102 individuals were collected, 273 juveniles and 829 adults, with CC ranging from 16.7 to 39.6 mm in males and 16.7 to 44.9 mm in females. Adults were captured predominantly in sampling stations with marine influence, while juveniles were found in all sampling stations, especially those with estuarine influence. The presence of the majority of juvenile individuals in the estuarine environment evidences the importance of the estuary in the ontogeny and protection of the species, since this environment presents physical barriers (wide variation of salinity) for its predators. The environmental factor that most influenced the juveniles was the temperature and the adults the salinity (Multiple Regression, p <0.05). The sex ratio was shifted in favor of females in the second year of the summer (Binomial test, p <0.05) and estimates of asymptotic length of males and females were, respectively, 36.4 mm and 44.2 mm, with Growth constants of 0.0067 and 0.0059 / day, and longevity of 686 and 774 days. The estimated average size in which half the population reached sexual maturity (CC50%) was 24.7 mm for males and 26.7 mm for females. The larger size of the females is related to reproduction (greater length of carapace results in a greater production of oocytes). Males with a higher growth constant, asymptotic length and lower longevity are the proposed standard for peneid prawns, and the difference in longevity may result from a number of causes, such as hormonal issues and reproductive costs. The results analyzed showed that the species completes its development in Cananéia and it can be considered a nursery for white shrimp.