Postglacial dispersal of longnose suckers, Catostomus catostomus, in the Mackenzie and Yukon Drainages

Abstract

The role played by stream transfers and reversals in the postglacial dispersal of fish populations in the Yukon and Mackenzie River drainages of Canada was analysed using genetic and meristic data from longnose sucker ( Catostomus catostomus Forrester) populations. The hypothesis the suckers dispersed from the Yukon River into the Mackenzie River via the Peel River was evaluated. Meristic data (gill rakers and lateral line scales) were uninformative for this analysis. Genetic affinity between the Yukon River and upper Peel River populations, and between Mackenzie and lower Peel River populations is suggested by transferrin allele frequencies. These affinities support the view that longnose suckers inhabiting the middle and upper regions of the Peel River are derived from Beringian and Mississippian ancestors, while suckers in the lower Peel are descended from Mississippian stock. Evidence for dispersal by way of the Eagle River was not found. Affinities of sucker populations in other river systems in the region are also described.