Reproduction and feeding biology of Sind Sardinella (Sardinella sindensis) from coastal waters of Qeshm Island, Persian Gulf

Sardinella sindensis is one of the dominant small pelagic fishes of Persian Gulf, especially in Qeshm Island's coastal waters. Investigation on some of the biological parameters of Sind Sardinella was carried out from April 2005 to March 2006. Sind Sardinella is economically the most important small pelagic fish species mainly caught by double boat purse seine in this area. Reproductive studies showed that peak maturity season occurred in May. The female to male ratio was calculated at 1:1.08 and chi-square analysis showed the difference in ratio was not statistically significant (P>0.05). LM_(50) is attained at a total length of 112 mm. The average absolute and relative fecundity were estimated to be 23396 (± 5337) and 739 (±117), respectively. This fish is planktonivore, and we found the diet of the species consisted of a broad spectrum of food types, but Crustaceans were dominant, comprising 44% of the food. The other major food groups and their share were Dinophyceae 17%, Bacillariophyceae 15%, Cyanophyceae 13%, fish eggs, larvae, scale 7% and finally Euglenahyceae, Chlorophyta, and others 4%. Analysis of monthly variation in the stomach fullness indicated that feeding intensity fluctuated throughout the year, with a high level during March and April. Vacuity index indicated this species is a semi-voracious fish