Estimating number of spawning white sturgeon adults from embryo relatedness

The goal for using genetic information derived from embryo samples is to gain insight into the reproductive biology of adult white sturgeon, Acipenser transmontanus Richardson. The relationship between egg development stages on the extraction of quality DNA was determined, and subsequent genotype data were used to infer contributing spawner numbers. White sturgeon DNA was present in extractions from all stages; however, pre‐gastrulation stage embryos generally failed to amplify sufficient genetic loci for analysis. Using experimentally created families, multivariate ANOVA and maximum‐likelihood sibship methods estimated the presence of 10 contributing parents from 11 actual adult spawners. It was observed that unidentified half‐sibling relationships (offspring sharing one parent) caused error for inferring parent numbers. Genetic methods estimated 13–40 parents potentially contributed to a collection of wild‐caught embryos, with variable numbers of parents inferred from separate spawning events (varying from 8 to 24). Egg source material provides a means to enhance the accuracy of annual spawning population size estimates, which is important for informing habitat restoration, harvest and water management decisions and recovery planning.