Thesis (BS Biology) -- University of the Philippines Mindanao, 2010

Acanthochromis polyacanthus is a reef fish that comprises a significant population of the coral reefs of Davao Gulf., but very few studies have been conducted regarding this species particularly on its reproductive biology. This paper investigated the reprodictive biology of this species by determining its pattern and seasonality. Specifically, it classified the gonad morphology of the species using a Gonadal Index and identified its stages of maturity. Furthermore, a Gonadosomatic Index (GSI) was used to identify the peak seasob of the species spawning period. It was determined that there are four stages of gonad maturity for A. polyacanthus, and male and female species have almost identical morphology except for the color of the gonads. Females have yellow to yellow-orange gonads while males have white to colorless gonads. For the GSI values, it was observed that the peaks in GSI were reached in the months of September and December. Data support that pattern observed for the gonad index of the species. Several gravid males and females were observed in September implying the species major peak of spawning period. It appeared that Spiny chromis has multiple spawning periods. The body length and gonad index relation showed females to attain sexual maturity at around 11 cm total lengths, whereas no significant trend was observed for male. For the body weight and gonad index relation, it showed that around 25 g in both sexes attain sexual maturity. In addition, significant correlation was observed for the body weight and gonad weight for females and not for males. The gonadosomatic index for females is 1.2 and 0.5 for males. The length and weight relationship data of spiny chromis species demonstrated growth coefficient of a = 0.01311 and b = 3.1222. these values were comparable to those values presented elsewhere