Determination of sexual dimorphism using morphometric techniques in Rachycentron canadum (Perciformes: Rachycentridae) cultivated in captivity

Abstract

Rachycentron canadum is a migratory and pelagic fish that is cultivated globally. Profitability of this fish is negatively affected by early sexual maturity. Monosex culture is amongst the strategies used to prevent early maturity. However, sexual dimorphism in R. canadum is not readily observable, difficulting the implementation of this type of monosex culture. In this study, we used morphometric techniques to determine sexual dimorphism by analyzing the shape and lengths of the fish. The ontogenetic allometry was also determined in order to deduce if dimorphism changes with the growth of the individuals. Distances and geometric morphometry revealed sexual dimorphism with regards to the position of the eyes, lips, pectoral fin, and ventral fin. The precision of the sexing of the individuals was 83.6 % and 98.1 % with distances and geometric morphometry, respectively. Although strong ontogenetic allometry was obtained, no disturbing effect on the discriminant function was observed.