The average monthly hepato-somatic indices for the years 200506 and 2006-07 showed an irregular trend in males and females (Fig. 8). In males the HSI values ranged between 1.1 (November) and 1.7 (September) and in females the corresponding values were 1.06 (November) and 1.8 (May). Besides storing energy in the muscle, the fish accumulates in the liver during periods of high energy intake and the relative size of liver can be correlated with the nutritional state of the fish and also with the growth rate (Busacker et al., 1990).Considering the spawning season of S. canaliculatus in the Omani waters, the drop in monthly HSI during June-July coincided with the minor spawning activity. However, prior to peak spawning season (November-February), the HSI dropped to the lowest in November in both males and females and abruptly increased in females than in males in subsequent months.