Abstract: With samples ofPentapodus caninus (coral reef fish)collected from Chenhang Island’slagoon area in Xisha Islands of the South China Sea in May and September 2018, weexamined the biological characteristics of P. caninus, including body length, body weight, sex ratio, gonad maturity, feeding intensity, fatness index, age and growth. The results showed that body length of P. caninus ranged 131-180 mm and 131-150 mm in May and September, respectively. There were significant differences in average value of body length and body weight between females and males in both months. The gonad maturity of P. caninus was mainly at stage Ⅱ. The proportion of mature female individuals was higher than that of male in May and September. Body length of female individuals at 50% maturity was 126.4 mm. The feeding stages of P. caninus were mainly at stage 1. The maximum mean feeding intensity occurred between 17:30 and 23:00 in May, with no significant difference in feeding intensity at the periods of 5:00-12:00, 12:00-17:30 and 17:30-23:00 in September. The fatness index of P. caninus did not change with increasing body length either in May or September. The allometric growth factor (b_value) between body length and body weight was 3.0856 and 3.0121 in May and September, respectively. The ages of 28 otolith samples were 0.51-1.12 years old, while the age of dominant group was 0.60-0.80 years old (39.29%). The parameters of the von Bertalanffy growth function between body length and age were: L_∞=263.77 mm, k=0.71,t₀=-0.52.

Key words: Pentapodus caninus, coral reef fish, fishery biology, South China Sea.