Classifying Vistula and Pomeranian sea trout populations using discriminant functions based on selected scale characters

This paper presents the results of studies of the effectiveness of a discriminant function system based on selected scale characters of sea trout populations from the Vistula River and Pomerania. Selected parameters of sea trout scales from comparable groups from the period prior to the mixing of the two populations were compiled and function effectiveness was tested. The reference discriminant functions obtained were used to classify the individuals from the mixed stock into corresponding groups. The best results (89.7% conformity) were obtained by applying the discriminant function to classify Vistula sea trout from the winter spawning run from Pomeranian sea trout. The lowest conformity at 64.6% was noted for the function segregating the sea trout from the two Vistula spawning runs. Discriminant analysis of the scale parameters and body length can be used in selection procedures which are used in the program to restore migratory fish species to Poland.