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Translocation as a mitigation tool: Demographic and genetic analysis of a reintroduced lake sturgeon (Acipenser fulvescens Rafinesque, 1817) population

Boothroyd, M., Whillans, T., Wilson, C. C.
Journal of applied ichthyology 2018 v.34 no.2 pp. 348-363
Acipenser fulvescens, adults, dams (hydrology), effective population size, fins, genetic analysis, genetic variation, genotyping, gillnets, juveniles, microsatellite repeats, parentage, parents, reproduction, streams, Ontario
This study assessed the establishment success of a translocation of adult lake sturgeon (Acipenser fulvescens) upstream of a hydroelectric dam in northern Ontario, Canada, using demographic and genetic data from juveniles and adults. The objectives of this study were to (i) assess the size and demographic structure of the reintroduced population; (ii) determine if juveniles are present; (iii) assess the genetic diversity of the reintroduced and source populations; and (iv) determine whether translocated adults are related to juveniles within the population. Gillnet and trotline sampling in multiple years (2002–2003; 2011–2016) resulted in the capture of many juveniles (n = 126) and some adults (n = 13) at the release site and downstream. The first fin ray of the left pectoral fin was collected for ageing and genetic analysis, and individuals were genotyped at 15 microsatellite loci. Age interpretations from the juvenile samples showed consistent cohorts starting in 2007 (2006–2012). Successful reproduction and recruitment by translocated adults was confirmed through genetic parentage analysis of microsatellite data, which linked juveniles to parents that had retained tags from the original translocation. Based on the microsatellite data, the genetic diversity of the reintroduced population (HO) was comparable to its source (HO = 0.57 ± 0.07 and 0.53 ± 0.06, respectively), although its estimated effective population size (Nₑ) was lower (Mattagami = 20.4 [13.5–30.5]; Adam's Creek = ∞ [72.0–∞]). These results suggest that the experimental translocation of wild adult lake sturgeon was successful, and highlight the value of treating translocation efforts as experimental reintroductions.