Reproductive biology of Japanese threadfin bream (Nemipterus japonicus) in the north-eastern coast of Persian Gulf

This investigation was carried in Hormuzgan province waters to study the reproduction of Nemipterus japonicus .The samples were collected bi-monthly (two times per season) from October 2011 to September 2012 . A total of 298 specimens were caught by bottom trawl and transferred to the Laboratory for further biological measurements consist of length measurement (Total length, Fork length and Standard length), body weight, gonad weight , gonad length , liver weight and sex determination.
The minimum and maximum fork length and body weight were 8 & 28 cm and 11 & 415 g, respectively. The b coefficient was estimated as 2.881, 2.515 and 2.804 for total (male & female), male and female groups. The sex ratio was M:F =1.0 : 2.9 . Based on reproduction studies, the spawning seasons were in two peaks of spring (as main one) and autumn. It was found that this species is a batch spawner fish. The mean absolute fecundity was 186819 ± 34200; and the LM50 was calculated about 21 cm.