Morphometric Analysis on Shape Transition during Growth of the Red Snapper (&amp;lt;em&amp;gt;Lutjanus campechanus&amp;lt;/em&amp;gt;, Poey, 1860)

Elvia Teresa Mendoza-Barrera,Monica Améndola-Pimenta,María Eugenia Vega-Cendejas,Rossanna Rodríguez-Canul

doi:10.4236/ojms.2018.84023

Abstract

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.

Highlights

geometric methods (GM) addresses comparisons between shapes during development focusing in the analyses of the Cartesian coordinates of the anatomical points that are of biological interest [4], and bases its methodology in the use of landmark coordinates (LM) that gather datasets of two or three coordinates
GM analyses are very useful for the study of organisms that have completed morphogenesis, and that are at different growth stages, where the homologous characters are identified throughout all the life stages [2] [9]
The LogCS had highly correlation with the standard length (r = 0.969, p < 0.01) (Figure 3(A) & Figure 3(B))

Summary

Introduction

GM addresses comparisons between shapes during development focusing in the analyses of the Cartesian coordinates of the anatomical points that are of biological interest [4], and bases its methodology in the use of landmark coordinates (LM) that gather datasets of two or three coordinates This method provides a robust tool to quantify the simple shape of a given geometric object without considering the effects of size, rotation, and translation, but conserving in this way information on the relative spatial locations of the data that allows the differentiation either at individual or at group level [7]. The benefit of a quantitative description is the accuracy that provides the ability to recognize intermediate shapes, to judge degrees of proximity or similarity to other shapes and to extrapolate or predict possible shape extremes [9] [10]

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