The genetic variability of whitefish, Coregonus lavaretus (L.), was studied based on 114 individuals from nine populations inhabiting Polish lakes, including the Szczecin Lagoon, and from one population each from lakes in Austria and Switzerland. Differences within and among populations were assessed with mitochondrial ND-1 gene sequences that were PCR amplified and digested with ten restriction enzymes. The ten composite haplotypes obtained were sequenced and analyzed with MEGA4 software. The highest intrapopulation variability was noted in the whitefish populations inhabiting lakes Ińsko, Miedwie, Marianowo, Wisola, Śremskie, Morzycko, the Szczecin Lagoon, and Lake Lucerne, which possessed from two to five composite haplotypes. In contrast, populations inhabiting lakes Woświn, Czarne, and Traunsee were fixed for the most common haplotype H2.
