Reproductive Development of Striped Mullet in Louisiana Estuarine Waters with Notes on the Applicability of Reproductive Assessment Methods for Isochronal Species

We assessed reproductive development of striped mullet Mugil cephulus from the coastal waters of Louisiana. Maturation of primary oocytes began in September of each year, and by October, a synchronous group of homogeneous, vitellogenic oocytes was observed (isochronal development). Based on indirect evidence, spawning occurred from November through early January. Gonadosomatic index (GSI) values varied with size among small, mature female striped mullet, but reached an asymptote for females 330 mm in fork length (FL) and larger. Anomalous development in certain ovaries strongly influenced GSI findings and produced excessively low values. Thus, it is suggested that histological examination be included in this type of reproductive study to identify factors that are responsible for high GSI variation. Potential fecundity correlated moderately well with female size and ranged from 2.7 × 105 to 1.6 × 106 eggs per individual for fish that ranged from 290 mm to 445 mm FL.