Reproductive Biology of Blue runner, Caranx crysos (Mitchell, 1815) From the Coastal Waters of Rio Grande do Norte, Brazil (Southwest Atlantic Ocean)

Abstract

Reproductive biology of blue runner, Caranxcrysos was investigated, based on the total body length, body weight, sex ratio, size at first sexual maturity, macroscopic developmental stages of gonads, ovarian histology, gonado somatic index (GSI), fecundity and the spawning season. The length-weight relationship for grouped sex was W=0.0346.LT2.6717. The sex ratio of the sampled population (n=116) was 1: 1.1 without any significant difference from the expected sex ratio. First sexual maturation in males and females occurred at 331 mm of total body length. The macroscopic characteristics of gonad development indicated immature, maturing, mature and spent stages. Histological analyses of ovary indicated the following oocyte developmental stages: early and late primary growth stage, cortical alveolar stage and early and late vitellogenic growth stages. GSI attained peak values from April to June and in January. Mature fish occurred during most part of the year, other than during February and October. This species has a prolonged reproductive period with peak periods of activity. C. crysos has a high reproductive output, providing population increase and exploitation of the environmental resources