Search

We compared the genetic diversity and structure of wild versus captive-propagated at-risk species of freshwater mussels in Canada, Lampsilis fasciola (wavy-rayed lampmussel; WRL) and Ptychobranchus fasciolaris (kidneyshell; KS), using microsatellite-generated genotypes. No significant differences were detected using Kruskal-Wallis tests that compared the genetic diversity metrics of wild and captive-propagated WRL (from 12 mothers) and KS (from seven mothers). After effective population size ([N.sub.e]) was estimated, considerable overlap was found in the estimated [N.sub.e] between wild and captive populations of both species. Pairwise [F.sub.ST] and [D.sub.est] values among wild WRL, hatchery-raised WRL juveniles, and across different time periods (2008-2018) were generally low ([F.sub.ST] = 0.007-0.043, [D.sub.est] = 0.005-0.282). Pairwise [F.sub.ST] and [D.sub.est] for KS were not significant and low (0.012, 0.017). When comparing captive-reared offspring with the wild population, STRUCTURE analysis revealed strong support for a single genetic population. With at least seven females contributing to brood stock, genetic diversity was maintained. Further research is needed to assess the male contribution to each glochidial brood as well as the variability of genetic diversity in individual glochidial broods. Nous avons compare la diversite et la structure genetiques de deux mulettes en peril au Canada, la lampsile fasciolee (Lampsilis fasciola, LF) et le ptychobranche reniforme (Ptychobranchusfasciolaris, PF), sauvages et issues de la propagation en captivite, en utilisant des genotypes generes a partir de microsatellites. Aucune difference significative n'est relevee entre les populations sauvages et propagees en captivite de LF (issues de 12 meres) ou de PF (issues de sept meres) a la lumiere de differents parametres de diversite genetique en utilisant des tests de Kruskal-Wallis. La taille effective de la population ([N.sub.e]) a ete estimee, et un chevauchement considerable est releve entre les [N.sub.e] estimees des populations sauvages et propagees en captivite des deux especes. Les valeurs de [F.sub.ST] et [D.sub.est] par paire de LF sauvages, de LF juveniles elevees en ecloseries et pour differentes periodes (de 2008 a 2018) sont generalement faibles ([F.sub.ST] = 0,007-0,043, [D.sub.est] = 0,005-0,282). Les valeurs de [F.sub.ST] et [D.sub.est] par paire de PF sont faibles (0,012, 0,017) et non significatives. Pour la comparaison de progeniture elevee en captivite a la population sauvage, les resultats de l'analyse avec le logiciel STRUCTURE appuient fortement l'interpretation d'une seule population genetique. Si au moins sept femelles contribuent au stock de geniteurs, la diversite genetique est maintenue. D'autres travaux de recherche sont necessaires pour evaluer la contribution des males a chaque emission de glochidies et la variabilite de la diversite genetique au sein de ces emissions. [Traduit par la Redaction], Introduction Freshwater mussels (Bivalvia: Unionida, unionids) are one of the most imperilled taxa on the planet, with 70% of unionid species in North America at risk of extinction (Williams et [...]

Obovaria olivaria is a species of freshwater mussel native to the Mississippi River and Laurentian Great Lakes‐St. Lawrence River drainages of North America. This mussel has experienced population declines across large parts of its distribution and is imperiled in many jurisdictions. Obovaria olivaria uses the similarly imperiled Acipenser fulvescens (Lake Sturgeon) as a host for its glochidia. We employed mitochondrial DNA sequencing and restriction site‐associated DNA sequencing (RAD‐seq) to assess patterns of genetic diversity and population structure of O. olivaria from 19 collection locations including the St. Lawrence River drainage, the Great Lakes drainage, the Upper Mississippi River drainage, the Ohioan River drainage, and the Mississippi Embayment. Heterozygosity was highest in Upper Mississippi and Great Lakes populations, followed by a reduction in diversity and relative effective population size in the St. Lawrence populations. Pairwise FST ranged from 0.00 to 0.20, and analyses of genetic structure revealed two major ancestral populations, one including all St. Lawrence River/Ottawa River sites and the other including remaining sites; however, significant admixture and isolation by river distance across the range were evident. The genetic diversity and structure of O. olivaria is consistent with the existing literature on Acipenser fulvescens and suggests that, although northern and southern O. olivaria populations are genetically distinct, genetic structure in O. olivaria is largely clinal rather than discrete across its range. Conservation and restoration efforts of O. olivaria should prioritize the maintenance and restoration of locations where O. olivaria remain, especially in northern rivers, and to ensure connectivity that will facilitate dispersal of Acipenser fulvescens and movement of encysted glochidia. [ABSTRACT FROM AUTHOR]

We compared the genetic diversity and structure of wild versus captive-propagated at-risk species of freshwater mussels in Canada, Lampsilis fasciola (wavy-rayed lampmussel; WRL) and Ptychobranchus fasciolaris (kidneyshell; KS), using microsatellite-generated genotypes. No significant differences were detected using Kruskal–Wallis tests that compared the genetic diversity metrics of wild and captive-propagated WRL (from 12 mothers) and KS (from seven mothers). After effective population size (Ne) was estimated, considerable overlap was found in the estimated Ne between wild and captive populations of both species. Pairwise FST and Dest values among wild WRL, hatchery-raised WRL juveniles, and across different time periods (2008–2018) were generally low (FST = 0.007–0.043, Dest = 0.005–0.282). Pairwise FST and Dest for KS were not significant and low (0.012, 0.017). When comparing captive-reared offspring with the wild population, STRUCTURE analysis revealed strong support for a single genetic population. With at least seven females contributing to brood stock, genetic diversity was maintained. Further research is needed to assess the male contribution to each glochidial brood as well as the variability of genetic diversity in individual glochidial broods. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Detection of rare species can be challenging and time‐consuming using conventional methods, but environmental DNA (eDNA) is becoming a commonly used tool for detection in conservation and management of species. This study demonstrates the utility of the precipitation method (precipitated and preserved in 3 M sodium acetate and 95% ethanol) for collection of eDNA to detect the seasonal distribution of the critically endangered Alabama sturgeon (Scaphirhynchus suttkusi). Surface and benthic water samples were collected across a wider geographic area than previously published for Alabama sturgeon eDNA. Surface and benthic samples both yielded detections and resulted in a similar proportion of positive detections to previous work. However, by sampling a greater portion of the distribution of the Alabama sturgeon, further insight was provided on potential sturgeon movement. The results of the precipitation method show that Alabama sturgeon detections increase during spawning months, and that the fish may be overwintering in the Tombigbee River. High detections from winter benthic samples suggest that habitat choice may play a role in detectability and highlight the need to consider natural history when designing environmental DNA studies. When designing environmental DNA collection for rare species, sampling design should factor in species ecology, habitat use, site characteristics, and specific questions driving the research. [ABSTRACT FROM AUTHOR]