Morphological, ecological and mtDNA sequence variation in coregonid fish from the Baunt Lake system (the Vitim River basin)

Abstract

We performed morphological, ecological and genetic analyses of taxonomically complex sympatric whitefi sh forms inhabiting the Baunt Lake system in the Vitim River basin, Transbaikalia. It was shown that the whitefi sh forms in this system clearly differed based on morphological traits, growth rate and diet. The most signifi cant differences were based on the number of gill rakers, while the number of lateral line scales was similar. These whitefi sh had distinct diets, namely euryphagous and planktivorous diets. We developed a phylogeny of mtDNA haplotypes among the whitefi sh species and populations from the Baunt Lake system and the headwater regions of the Ob and Yenisei River basins. A morphologically homogeneous cisco-like whitefi sh sample revealed two distinct mitochondrial lineages. A strong genetic divergence between the fi rst mitochondrial lineage of cisco-like whitefi sh and all of the studied whitefi sh forms was revealed. We analyzed alternative hypotheses regarding the ori gin of cisco-like whitefi sh and the densely rakered whitefi sh form from the Baunt Lake system.