Seasonal changes in hepatosomatic index during reproductive cycle of golden trevally (Gnathanodon speciosus)
Abstract
Golden trevally (Gnathanodon speciosus) is a marine species of high economic value with strong potential for commercial aquaculture. The relationship between the hepatosomatic index (HSI) and the reproductive cycle was investigated in broodstock with average body weight and total length of 900 ± 200 g and 40 ± 5 cm, respectively. The HSI varied monthly in both females and males. In females, HSI ranged from 1.15 ± 0.25% to 1.69 ± 0.26%, while in males it ranged from 1.06 ± 0.15% to 1.59 ± 0.26%. In females, HSI differed noticeably among ovarian developmental stages, peaking at stage III (vitellogenic stage) 1.7 ± 0.5%. Conversely, in males, HSI showed little variation and no statistically significant differences (P > 0.05) among testicular developmental stages. These results indicate that the liver plays an important role in vitellogenesisin females, whereas HSI is not a useful indicator for estimating testicular developmental stages in males.