Contribution to the feeding habits and reproductive biology of narrow-barred Spanish mackerel, Scomberomorus commerson (Lacèpéde, 1801) (Teleostei: Scombridae), in the northern Persian Gulf

In this study, the feeding habits and reproductive behavior of narrow-barred Spanish mackerel, Scomberomorus commerson, in the northern Persian Gulf during five months from October 2011 to December 2012 have been investigated. Specimens were purchased from the fishermen at several landing sites. Feeding and nutrition results showed that sardines are the major prey items of S. commerson. Secondary prey species included ponyfish, halfbeak and Indian mackerel fishes. Mature females (Stages III, IV) were mostly observed between April to July. By July, most of the studied fishes were in recovery or spent stages (Stages IV, V) indicating the end of the spawning season. The result of gonado-somatic index (GSI) study in 184 male and female specimens indicated the highest reproductive activity from April to July with the peak in July. The total sex ratio of 69 males and 115 females was 0.6:1 and it was not significantly different during study periods except autumn season. The minimum and maximum cavity index (CV) for both sexes were from 22.5% in December to 68.0% in October, respectively. Sardines were the most prevalent components of the diet of S. commerson. Based on the obtained results, it can be suggested that that banning of the Spanish mackerel catch in the June-July, which is the peak of spawning period, may help brood stocks. Banning the sardine catch may also benefit management of S. commerson in the Persian Gulf.