PROTANDRIC SEX CHANGE IN CENTROPOMUS UNDECIMALIS, THE COMMON SNOOK

Otolith increment morphology of the protandric hermaphrodite Centropomus undecimalis (snook) was analyzed in relation to age and length for sex specific growth differences to retroactively determine the time of sex change. Growth spurts in the otoliths of female snook, the terminal sex, were identified between ages 4 and 8, corroborating the current understanding of when sex change occurs (between 3 and 8). No such growth increases were identified on the otoliths of male snook, the primary sex. Otolith growth, however, was found to decouple from length, so these growth spurts are not reflected in the length of the fish. This study marks the first time that a distinct growth pattern differentiating the primary and terminal sexes, similar to that seen in the protogynous transitional growth spurt hypothesis, has been identified on the otoliths of a protandric species.