Parentage analysis reveals reproductive behaviors in a wild population of White Sturgeon

ABSTRACT Objective Reproductive activity is rarely observed directly in the White Sturgeon Acipenser transmontanus because spawning generally occurs over benthic habitats in fast-flowing rivers. Aspects of reproductive ecology have been inferred from indirect lines of evidence, with results often being imprecise. Here we performed parentage analysis within the population of the upper Columbia River, associating adults with offspring that had been collected from multiple years and locations, to precisely characterize spawning periodicity across years, spawning duration within years, and spawning site fidelity across locations. Methods We identified parent–offspring relationships by integrating Mendelian-mismatch-based exclusion, likelihood-based assignment, and relationship coefficient analysis, using tetrasomic single-nucleotide polymorphism genotypes that were produced through genotyping-in-thousands by sequencing. The thresholds for each approach were determined from known parent–offspring relationships in a cultured population. Results Parent–offspring relationships associated adults of both sexes with multiple spawning events across years, within years, and across locations. Among adults that were linked to multiple years, spawning periodicity ranged from 1 to 5 years in males and 4 to 5 years in females. Among adults that were associated with multiple spawning dates within years, we observed spawning durations of up to 26 d in males, whereas females largely displayed durations up to 4 d. Individuals of both sexes were associated with different sites in different years, whereas males were further linked to different sites within years, suggesting incomplete spawning site fidelity. Conclusions These findings inform an ongoing conservation aquaculture program for supplementing this population and demonstrate the utility of parentage analysis for inferring reproductive behaviors in high detail, particularly in systems where thorough sampling of parents and offspring is feasible.