Stock differentiation studies of whiting. Merlangius merlangus euxinus, from the Turkish Black Sea coast were carried out using morphometric and meristic characters and applying the generalised distance of Mahalanobis. Fifteen morphometric measurements, together with eleven meristic characters, were used in the analyses. Insufficient differences (P>0.01) in general phenotypic and genotypic characteristics implied the existence of a single unit stock. Samples taken in different periods showed lower similarity than those taken in the same periods.