Genetic estimation of evolutionary and contemporary effective population size in lake sturgeon (Acipenser fulvescensRafinesque, 1817) populations

Abstract

Summary The potential of sturgeon species and populations to adapt to current challenges and changing conditions will depend on their adaptive resources and capacity, which can be inferred from their genetic effective population size (Ne). Existing microsatellite genetic data from published studies were used to estimate Ne of lake sturgeon (Acipenser fulvescens) across hierarchical spatial and temporal scales. Previous analysis of mitochondrial DNA data suggested that the species has an evolutionary female effective population size (Nef) of ~8000, substantially lower than other North American freshwater fish species with similar distributions. Phylogeographic data were used to reconstruct the genetic makeup and diversity of phylogeographic lineages, and compare the genetic diversity and Ne of contemporary Canadian populations to their ancestral founding populations. A similar approach was used to estimate ancestral Ne for fragmented populations in formerly continuous habitats. On the finest spatiotemporal scale, point estimates of Ne for sturgeon populations in contiguous river fragments were compared against Ne values from reconstructed ancestral (pre-fragmentation historical) populations to assess changes in Ne since fragmentation occurred. These results illustrate the versatility of genetic data for estimating historical demographics of sturgeon, as well as providing information on their adaptive potential and long-term sustainability if given the ecological opportunity.