Punctuate divergent evolution in fish from the Northern Pacific

The mtDNA divergence was examined in some families of anadromous and semi-anadromous fish. Heterogeneous distribution of the divergence values along the scale was demonstrated. Statistically significantly higher number of the species pairs were characterized by divergence values ranging from 2 to 4% and 5 to 12% of nucleotide substitutions. These results suggest that in different monophyletic groups occupying common historical ranges, divergence-associated speciation often happened within similar time intervals. Comparison of the species divergence time calculated using the molecular clock pointed to the coincidence of the radiation periods in the taxa with paleogeological and paleoclimatic global changes in the history of Northern Pacific.