The uses of Otolith shape in discrimination of the sand sole (Solea lascaris, Risso 1810) population

In this study three samples of the sand sole (Solea lascaris, Risso 1810)otoliths were compared for the shape (on the length standardized Wavelet/Fourier coefficients), for weight and for five morphometric characters (mean.radii, otolith.area, otolith.length, otolith.perimeter, otolith.width), In order to verify if these three groups of the sand sole are coming from three different regions (ESSAOUIRA, IFNI and AGADIR) belongs to the same population. The result show significant difference between the three groups in the same way for morphometric and shape analysis of the otoliths, for weight comparison, the otoliths of ESSAOUIRA is heavier than IFNI and AGADIR. These results are supported by the discriminant linear analysis that shows a classification percentage of 80% on Fourier standardized coefficient, and by the principal component analysis (PCA) which expresses 75.75% and 21.42% for the first and second axes respectively on the morphometric variables. The shape and morphometric analysis was carried out with shape R package which is software package that runs on the R platform and is specifically designed to study otolith shape variation among fish populations. All these difference existing between the three groups can be related to the environmental specificity and to the population adaptation for each environment.