Multivariate analysis of hybridizing Cyprinidae from the Kananaskis Reservoirs, Alberta

Abstract

Principal components and canonical variates analyses of hybridizing Couesius plumbeus (lake chub) and Rhinichthys cataractae (longnose dace) from Upper and Lower Kananaskis Reservoirs, Alberta, using 21 morphological characters, revealed two parental groups bridged continuously by an intermediate hybrid group. This morphological overlap between the hybrids and the parental species indicates that it is not always possible to positively identify "pure" parental individuals from the Kananaskis. Neither backcross nor hybrid F2 individuals could be identified from the analyses, although the Kananaskis R. cataractae showed effects suggestive of either selection or introgression, relative to known R. cataractae from widespread Alberta localities. Rhinichthys cataractae has also declined in numbers relative to C. plumbeus since last studied in 1961. Couesius plumbeus does not show similar effects suggestive of selection or introgression.