Morphometric Analysis on Shape Transition during Growth of the Red Snapper ( Lutjanus campechanus , Poey, 1860)

The red snapper Lutjanus campechanus (Poey, 1860) has a high commercial value that sustains an important fishery in Mexico. In this study, the patterns in morphological variations from early juvenile to adult stages were assessed by geometric methods (GM) in 194 organisms. Changes in shape were more evident and rapid in the early juvenile stage and decreased during adulthood. The principal components analysis of shape (Relative Warp Analysis, or RWA) identified size and body depth as the main sources of variance associated to both juvenile and adult organisms. The outline of the head and the tail showed the most noticeable differences following the ontogenic pathway visualized by thin-plate splines indicating that the ontogenetic pathway of the upper half and the lower half of the dorsal head profile (DHP) are in relatively opposite directions than those from the tail that bends ventrally. The Two-Block Partial Least Square analysis (2B-PLS) and their CR coefficients showed that the two modules had a moderate linear trend (p = 0.001). Although the blocks have morphological changes at different rates, there is a moderate synchrony in growth by modules. This study is the first to report the use of geometrical morphometry in L. campechanus in Mexico.