Reproductive biology of brownstripe snapper Lutjanus vitta (Quoy and Gaimard, 1824) from West Sulu Sea, Philippines

Abstract

The reproductive biology of Lutjanus vitta from the West Sulu Sea, Philippines was investigated by monthly sampling from October 2012 to December 2013. The reproductive activity was assessed to: characterize the sex ratio, determine the spawning period, estimate length and age at maturity (L50, A50) and determine the batch fecundity (BF). The overall sex ratio differed significantly (p < 0.05) among size classes and months with male and female dominance, respectively. As expected for tropical fish, spawning occurred year-round with two main spawning periods (April and October). The highest gonado-somatic index (GSI) values were recorded with two peaks for females in April (2.53%) and October (2.48%), which correspond to the two main spawning periods and one peak for males in April (1.55%). Males reached the length and age at sexual maturity (L50 = 22.8 cm, A50 = 2.19 yrs.) and females (L50 = 21.3 cm, A50 = 1.76 yrs) indicating that sexual maturation differed by age and size across sexes. Fecundity increased exponentially with fish length and weight demonstrating a non-linear relationship between fecundity and fish size.

Keywords

• Reef fish
• Reproductive seasonality
• East coast Palawan
• Lutjanidae