Reproductive Biology of the Indian Mackerel, Rastrelliger kanagurta (Cuvier 1817), from Salalah, Dhofar Coast, Oman

The present study aims at determining the length-weight relationship, sex ratio, relative weight, gonadosomatic indices and length at 50% maturation for the Indian mackerel, Rastrelliger kanagurta (Cuvier, 1817). A total of 791 specimens were collected from Salalah in the Dhofar region during the years 2007 to 2009. For both sexes, a common length-weight relationship was derived from the analysis, that is $W=0.00001×L^{3.4}$. It was found that the Omani Indian mackerel spawned during August to November and the lengths at 50% maturation were 271 mm for the combined sexes, 267.5 mm for the females and 277.5 mm for the males. The relative condition weight was positively proportion to the gonadosomatic index. The mean sex ratio for the entire fish sample of 0.56±0.1 was significantly different from the anticipated theoretical sex ratio of 0.5 $(X^2 = 8.77; \;df = 1; \;p<0.05)$.