Biologia reprodutiva do cangulo-preto (Melichthys niger, Bloch, 1789) capturado no Arquipélago de São Pedro e São Paulo - Brasil

Abstract

The black triggerfish, Melichthys niger, is a fish of family Balistidae, which consists of 11 genera and 40 species. Possessing a coloration ranging from dark blue to black with green metallic reflections, can reach up to 50 cm in total length, with a distribution circumtropical. In this work we examined specimens of black triggerfish , obtained from commercial fishing in the archipelago of Saint Peter and Saint Paul-ASPSP (00 ° 55'02 "N and 29 20'42" W), from January 2006 to May 2008. Soon after capture, specimens were identified and measured, which sent up its total length (TL) and standard (CP). Next, all specimens were dissected to allow the collection of the reproductive system, which were fixed in formalin 10% and was then packed in plastic drums, until their arrival at the laboratory. During the study period, 777 individuals were analyzed, of which 367 were females and 410 were males. Females ranged from 19.0 to 32.0 cm total length, and males from 21.0 to 37.4 cm. From histological analysis was possible that the ovaries of M. niger are composed of ovigerous lamellae containing oocytes at different stages of development. We identified five different stages of oogenesis: young cells, pre-vitellogenic oocytes (perinucleolar) oocytes, cortical alveolar, vitellogenic oocytes and mature oocytes. In addition to the germ cells were also identified some somatic structures composing the ovary: ovary wall, follicular cells and blood vessels. The monthly distribution of maturation stages, from analysis of ovaries indicated a higher frequency of mature females during the first half of the year in the archipelago of Saint Peter and Saint Paul.