Assessment of maturity, spawning, and ovarian cycle of sand whiting (Sillago sihama) from the north coast of Gulf of Oman

Sillago sihama is the most widespread and abundant member of the smelt-whiting family Sillaginidae and major economic importance throughout the Indo-Pacific. Investigations on the sexual maturity, spawning, and fecundity of S. sihama from the Northern coast of Gulf of Oman were carried out from September 2016 to August 2017. The total number of 676 fish with a total length of 10.44-25.4cm and the total body weight ranged between 11.86-124.53 g were used for this study. Females’ species predominated in the sampled population and were larger than the males. The study found that the overall sex ratio was 1 male to 1.2 females, diverging significantly from 1:1. Comparison in the histological findings between macroscopic observations and GSI values determined five developmental stages for males and females. These findings revealed that S. sihama spawn in April and May and continued until June. The ova diameter frequency distributions in mature component indicated that its spawning is prolong and the release of ova is a single batch. Nearly, all males and females became maturate approximately in over 165 mm and 167 mm, respectively. The results showed that the fecundity had positive correlation with the length and body weight. Furthermore, the absolute fecundity varied from 21345 to 73781 ova and there was a linear relationship between absolute fecundity and fish size for all species tested.