Document Type : Research Paper
Shahid Beheshti University
Iranian Fisheries Research Organization
Scomberoides commersonnianus is one of the commercially important fishes of the family Carangidae. In this study, 563 specimens (292 males, 247 females, and 24 sexually unknown ones) were collected from the north-west of the Persian Gulf. Length-weight relationships and condition factors were determined for each sex in four length classes within different seasons. In general, the growth pattern in this fish was negatively allometric and the length-weight relationship in all specimens amounted to W= 2.9109FL-1.8424. The growth pattern of all specimens was negatively allometric in spring and autumn and isometric in summer and winter. Also, growth pattern was positively allometric in 8-31 class, negatively allometric in 31-54 cm and 54-77 cm classes and isometric in 77-100 cm class among all specimens. The condition factor in the 8-31 cm, 31-54 cm and 54-77 cm length classes was greater in males than in females, but in 77-100 cm length class it was more in females than in males, which is probably due to the increase in ovary weight in this class. Also, the condition factor in males exceeded that of females in spring, autumn and winter however, it was greater in females than in males during summer. In this season, females were in better condition owing to an increase in the weight of ovaries. The results demonstrate that growth pattern and condition factor vary in different seasons, lengths and sexes because of change in feeding intensity and the time of reproduction.