ReproduÃÃo, idade e crecimento da carÃna-azul Acanthurus coeruleus (Actinopterygii: Acanthuridae) em Pernambuco

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Acanthurus coeruleus plays a very important role in the reef environment of the Tropical Atlantic Ocean because it is one of the main herbivorous forager in this ecosystem. In Pernambuco, its exploration has happened indiscriminately in the trap-fisheries, however, this species has not been much studied, which explains the lack of knowledge about most aspects of its reproduction and growing. From March 2006 to July 2007, 536 samples have been collected from the coastline of Pernambuco. For the reproduction studies were analyzed the sexual proportion, the length of first maturation, the period of spawning, the fertility and the type of spawning. Through the monthly variation of the percentage of males, females and of mature individuals, the gonadosomatic index and through the counting and measure of the oocytes diameter. In order to grow, the otoliths have been cut, sanded, polished and read. The growing parameters have been estimated according to the von Bertalanffy model, in which the medium lengths were retrocalculated at each age. Thin blades were made in order to estimate the age of the larva settlement and the inverted model was used to estimate the age of the first sexual maturation. To analyze the month in which the growing structure was formed, the marginal development was applied. The sexual proportion was 1F:1,11M, showing little significant difference (x2, p<0,05). The spawning period happened between November and February, and it has been found a L50 in the females of 14,25cm and 14,13cm as the total length in the males. The species presented its spawning in allotments and its average fertility was 26798 oocytes. The individuals presented maximum age of 12 years old, whose growing parameters were: L∞ = 52,22 cm, K = 0,08 and T0 = -0,14. The ages of the first maturation and of larva settlement was 3,2 years and 51 days, respectively. This way, the bluetang is a fish that has a slow growing, with a long life span, large number of oocytes produced, in spite of a high larval mortality, reaching a late maturation. Therefore, it is very vulnerable to fishing.

ASSUNTO(S)

caraÃna-azul growth zoologia acanthurus coreuleus acanthurus coeruleus biologia reprodutiva pernambuco reproductive biology

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