Reproductive biology of oriental sole, Brachirus orientalis, in Northern Persian Gulf

Abstract

Reproductive characteristics of 300 specimens of oriental sole (Brachirus orientalis) in the Persian Gulf were studied by monthly sampling from August 2015 to July 2016. Male and female ages were between 3+ to 11+ and 3+ to 17+ years, respectively. The sex ratio was 1M:2.2F. The most frequent age group in males was 7+ and in females was 11+ years. The highest value of condition factor for males was observed in August. The minimum, maximum and average absolute fecundity were 22000, 174000 and 82000), respectively. The highest value of gonadosomatic index (GSI) for males was in April and October. The highest of hepatosomatic index (HSI) for males and females was in February, but was not significantly different from September and April (P>0.05). Based on GSI, egg diameter and monthly frequency distribution of different stages of ovarian maturation, it was determined that the fish has two prolonged spawning seasons, one from July to November with a peak in September (3.4) and the other from February to May with a peak in April (4.5). The long spawning season indicated that this fish is a multiple spawner with asynchronous ovaries.