Reproductive biology of largescale tonguesole Cynoglossus arel in coastal waters of Bandar Abbas, Persian Gulf, Iran

The objectives of this study were to determine the reproductive cycle of largescale tonguesole Cynoglossus arel, a commercially valuable flatfish species, in coastal waters of Bandar Abbas, along the south coast of Iran in the Persian Gulf. From October 2009 to September 2010, 905 fish were collected in monthly samples, and their length, weight, sex, gonad weight, and maturity status recorded. These data revealed that ovary weight in females is low from July to September, then increases to a peak in February followed by a decrease, indicating that the peak spawning season is from February to March with some spawning lasting until June. Males showed a corresponding seasonal pattern in testis weight, although with much less pronounced seasonal differences than gonad weight in females. Five maturity classes were described based on ovarian and testicular histology, corresponding with macroscopic analysis of gonads. The spawning season in C. arel is prolonged, similar to several other tropical flatfish species, and larger adult females tended to have an even more prolonged spawning period than smaller, presumably younger adult females. Combined, our results indicated that C. arel is a winter-to-spring batch spawner with an asynchronous type of ovarian development.