Parentage assignment in the critically endangered European sturgeon (Acipenser sturio) based on a novel microsatellite multiplex assay: a valuable resource for restocking, monitoring and conservation programs

The only remaining population of the critically endangered European sturgeon, Acipenser sturio, is located in the Gironde basin (France). A restoration program initiated 20 years ago has allowed more than one and a half million individuals to be stocked. Effective monitoring of this population is a key prerequisite in ensuring the sustainability of this species in the wild. We report the development of a novel microsatellite multiplex assay for genetic monitoring of A. sturio. Diversity of a set of 18 loci was low to moderate, with a number of alleles and observed heterozygosity ranging from 4 to 7 and 0.33 to 0.74 respectively, depending on markers. A set of captive-born progeny of known relatives (n = 72) was used to examine the efficiency of this assay in assigning parentage to offspring. Three different programs were used. Correct assignment success was generally high (above 90 %), but differed between programs. Parentage analysis of individuals captured in the Gironde estuary (n = 193) demonstrated that most offspring (91.2 %) are unambiguously allocated to parent pairs from the broodstock. Our research provides an efficient and accurate method for the genetic monitoring of the restocking program, but also for others aspects of conservation, including genetic diversity evaluation, effective population size estimation, and inbreeding assessment.