Maturation and spawning of Johnius dussumieri (Cuv. and Val.)

Abstract

Investigations dealing with the maturation and spawning of the Sciaenid, Johnius dussumieri, were carried out to determine the spawning season, spawning periodicity, fecundity and the ponderal index. The growth of the ovaries and the ova and the changes occurring in them in different stages of maturity have been described. Sex composition during different months and the size at first maturity were studied. Spawning seasons based on the monthly analysis of maturity stages of females were determined. With the help of ova-diameter measurements the spawning periodicity was assessed. Fecundity was correlated to total length and weight of the fish. Ponderal index or condition factor was studied in relation to size and spawning seasons.