In the sampled specimens, in addition to genetic analyzes, morphological ones concerning 7 phenotypic classifications are also carried out, including the analysis and comparison of the so-called “parr spots”.

It is a matter of observing 9-13 large ellipsoidal blue-grayish spots present along the median region of each side, sometimes divided or fragmented and / or stripes on the side of the fish consisting of the alternation of four darker bands and three lighter bands ( in some populations parr spots are the most evident character, while in others, with marked stripes, they are almost not noticed).

In the picture, in comparison, the parr spots of a native specimen, numerous and fragmented, with those of an allochthonous trout, regular and rounded.