Title : Incongruence between morphological and genetic data of Scomber colias in Tunisian waters
Abstract:
The Atlantic chub mackerel Scomber colias (Gmelin, 1789) is one of the important fisheries resources in Tunisian waters. The best management of this resource needs the knowledgement of populations differentiation. Therefore, morphological study including 13 morphometric, 4 meristic characters and sequences of mitochondrial DNA control region were carried out from three distant sampling sites along the coast of Tunisia in order to test a possible differentiation between the three populations.
Morphologic analysis of adults specimens revealed statistically significant differences for 13 standardized morphometric measurements and 2 meristic characters (the number of branchial spins Right(BrR) and Left (BrL)).In fact, in morphometric traits, the overall assignments of individuals into their origin groups were 83.87% for the morphometric variables and 49% for the meristic data, respectively. However, the genetic study revealed the absence of genetic structure between the three populations with a lower and insignificant fixation index (ΦST=-0.004, P=0.701).
Despite the non-convergence between the genetic and morphological data, a possible signal of differentiation between 3 groups of Scomber colias which belonging to the same population seems plausible. In future, geometric morphometry and microsatellites markers are required to confirm our results.
