Reproductive strategy of rivulated parrotfish Scarus rivulatus Valenciennes, 1840

Abstract

The rivulated parrotfish Scarus rivulatus is a reef fish that use not to be a target fish, but is now becoming a fisheries target. This change in status is causing the rivulated parrotfish population to be depressed due to fishing effort and interspecific and intraspecific competition in their habitat. This research aimed to examine the parrotfish’s reproductive strategies and tactics. The parameters observed were sex ratio, gonad maturity and first maturity at the female and male. Sex and gonad maturity was determined based on the macroscopic characteristics of the gonads. First maturity was estimated based on the total length. This study indicates that the sex-ratio of rivulated parrotfish was unbalanced, males was fewer than females (1: 2.49). The maturity stages of male and female were quite synchronous. Early maturation and maturity stages that were dominant during the study indicate that rivulated parrotfish can spawn at any time throughout the year. The size at first maturity of rivulated parrotfish was achieved very quickly with sizes 16.9 for female cm and 24.3 cm for male. Females that mature more quickly are an indication that the rivulated parrotfish is protogynous. An imbalance in sex ratios, spawning at any time throughout the year, early maturity, and protogynous could be a strong indication that rivulated parrotfish was an r-strategy.