[On the Population Genetic Portrait of Kaluga, Acipenser dauricus Georgi, 1775 Analysis of Sequence Variation in the...

The variability of the mtDNA D-loop was examined in kaluga endemic to the Amur River, which is classified as critically endangered by the IUCN Red List of Threatened species. Sequencing of the D-loop fragment (819 bp) in 122 kaluga specimens collected in Lower Amur revealed 27 unique genotypes. The sample was characterized by a relatively low level of haplotypic (0.927) and nucleotide (0.0044) diversity. No considerable deviations from the neutral mutation model of DNA polymorphism were observed. Overall, the mismatch distribution patterns and the results of testing of simple demographic models (sudden demographic expansion and exponential population growth) pointed to a past increase in the number of kaluga sturgeons. According to the Bayesian skyline, the kaluga population doubled over the last two to three thousand years. The number of mature females in the modern kaluga population and the assessment of their long-term effective population size (Nef) are roughly at the same level (about three thousand individuals), which confirms the validity of assigning kaluga to the category of species on the brink of extinction.