Genetic Population Structure of Remnant Lake Sturgeon Populations in the Upper Great Lakes Basin

Abstract

Abstract.-Populations of lake sturgeon Acipenser fulvescens have undergone dramatic declines in abundance and distribution in the Great Lakes basin and are a species of conservation concern throughout their range. While information regarding the genetic population structure of this species is critical for the development of effective management plans, little information currently exists. We examined both microsatellite and mitochondrial DNA (mtDNA) variation as a means of estimating population genetic diversity within, and the degree of spatial population structuring among, 11 remnant lake sturgeon populations in the upper Great Lakes basin. Multiple measures of genetic diversity were consistently high across populations and were not significantly correlated with estimates of current adult population size. Despite substantial population declines, life history characteristics, including longevity and iteroparity, appear to have buffered lake sturgeon populations from losses of genetic diversity. Significant levels of interpopulation variance in both microsatellite allele and mtDNA haplotype frequencies (mean genetic differentiation index ¼ 0.055 over eight microsatellite loci; mean haplotype frequencies ¼ 0.134 for mtDNA) were detected. Population structure is most likely a function of high levels of natal fidelity, a trend observed in other species of sturgeon Acipenser spp. We discuss the implications of these results with regard to the management and conservation of lake sturgeon in the Great Lakes.

Genetic assessment of straying rates of wild and hatchery reared lake sturgeon (Acipenser fulvescens) in Lake Superior tributaries

“…Consequently, homing to natal sites can facilitate the evolution of beneficial site-specific genotypic and phenotypic adaptation over time. In sturgeon species, existing data suggest some degree of homing associated with natal philopatry (Auer, 1996;Stabile et al, 1996;Tranah et al, 2001), resulting in genetically distinct populations (DeHaan et al, 2006;Welsh et al, 2008).…”

“…Our genetic-based approach to detecting migration eliminates this problem. The development of highly variable genetic markers, such as microsatellite DNA, has allowed for discrimination among different lake sturgeon populations (DeHaan et al, 2006;Welsh et al, 2008), thereby facilitating assignment of population of origin on an individual basis. Numerous studies on sturgeon species have successfully utilized multi-locus microsatellite genotyping techniques for a variety of purposes (Stabile et al, 1996;Tranah et al, 2001;Israel et al, 2004;Bott et al, 2009).…”

Evaluating the genetic consequences of river fragmentation in lake sturgeon (Acipenser fulvescens Rafinesque, 1817) populations

“…Habitat degradation and fragmentation by dams continues to decrease their abundance and impede restoration efforts (Schueller and Hayes, 2011) by altering spawning behavior and reducing recruitment (Auer, 1996b;Haxton and Findlay, 2008). Despite significant declines in abundance, neither this study nor others (DeHaan et al, 2006;Drauch and Rhodes, 2007;Welsh et al, 2008;McDermid et al, 2011;Wozney et al, 2011) have observed significant decreases in genetic variability or evidence of inbreeding within populations of Lake Sturgeon. It is believed that the sturgeon are buffered from expected losses of genetic diversity because of their longevity and overlapping generations.…”

“…Neraas and Spruell, 2001;Meldgaard et al, 2003;Yamamoto et al, 2004). For some long-lived threatened and endangered fish species, however, observed anthropogenic declines in population abundance have not been mirrored by similar genetic changes (DeHaan et al, 2006;Lipp e et al, 2006;Reid et al, 2008;McDermid et al, 2011;Wozney et al, 2011). The long generation times of these species may buffer against genetic loss within and among river fragments over the time scales studied to date (Lipp e et al, 2006;Reid et al, 2008;McDermid et al, 2011;Wozney et al, 2011).…”

Evaluation of a remnant lake sturgeon population’s utility as a source for reintroductions in the Ohio River system

“…Pairwise estimates of genetic divergence suggest that the greatest levels of structure exist among populations originating from different major drainages, concordant with previous findings (McQuown et al 2003). Significant genetic differentiation was observed among several populations within drainages, including comparisons between fish from the Sturgeon River and Peshtigo River (Great Lakes Basin), as found by DeHaan et al (2006). This indicates that for lake sturgeon, the selection of a within-drainage source population for reintroductions might be preferable to reduce the possibility of outbreeding depression.…”