Inference that more than one genetic stock of walleyes Sander vitreus was present in Claytor Lake, Virginia, and its main influent, the New River, raised questions concerning the spawning movements, locations of spawning grounds, and home range of resident stocks. We conducted a radiotelemetry study of 52 walleyes in Claytor Lake and the upper New River over a period of 2 years. Our findings support the hypothesis that two populations coexist within the system, exhibiting different home ranges, spawning movements, and spawning grounds, even though there is no physical barrier to movement between the spatially disjunct populations. Walleyes living within Claytor Lake mostly spawn at the first riffle area above the reservoir, whereas those living in the New River mostly spawn at two riffle areas well upstream. Coexistence of distinct populations in the system justifies different management strategies. Management of the walleye population in Claytor Lake should focus on increasing the exploitation of the nonindigenous lake stock. Management of the upper New River walleye population should focus on conservation of the unique river stock through supportive breeding, strict harvest regulations, or both.
"The predisposition of individuals to return to natal waters for reproduction has been widely described in many fishes and has important consequences at the individual and population levels (Leggett, 1977; Miller et al., 2001; Palmer et al., 2005). The ability of individuals to migrate to a distinct spawning area or to reside in a particular region often will result in reproductive isolation among populations (Leggett, 1977). "
[Show abstract][Hide abstract] ABSTRACT: Natal philopatry in lake sturgeon (Acipenser fulvescens) has been hypothesized to be an important factor that has lead to genetically distinct Great Lakes populations. Due to declining abundance, population extirpation, and restricted distribution, hatchery supplementation is being used to augment natural recruitment and to reestablish populations. If hatchery-reared lake sturgeon are more likely to stray than naturally produced individuals, as documented in other well-studied species, outbreeding could potentially jeopardize beneficial site-specific phenotypic and genotypic adaptations. From 1983 to 1994, lake sturgeon propagated using eggs taken from Lake Winnebago adults (Lake Michigan basin) were released in the St. Louis River estuary in western Lake Superior. Our objective was to determine whether these introduced individuals have strayed into annual spawning runs in the Sturgeon River, Michigan. Additionally, we estimated a natural migration rate between the Sturgeon River and Bad River, Wisconsin populations. Presumed primiparous lake sturgeon sampled during Sturgeon River spawning runs from 2003 to 2008 were genotyped at 12 microsatellite loci. Genotypic baselines established for the Sturgeon River (n = 101), Bad River (n = 40), and Lake Winnebago river system (n = 73) revealed a relatively high level of genetic divergence among populations (mean FST = 0.103; mean RST = 0.124). Likelihood-based assignment tests indicated no straying of stocked Lake Winnebago strain lake sturgeon from the St. Louis River into the Sturgeon River spawning population. One presumed primiparous Sturgeon River individual likely originated from the Bad River population. Four firstgeneration migrants were detected in the Sturgeon River baseline, indicating an estimated 3.5% natural migration rate for the system.
Journal of Great Lakes Research 12/2010; 36(Dec 2010):798-802. DOI:10.1016/j.jglr.2010.08.011 · 1.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Habitat utilization and movements of walleyes in Otsego Lake were studied from April through November 2006 using acoustical tags. Tagged walleye were primarily found in the shallow, weedy areas at the north end of Otsego Lake in less than 20 feet of water. On average males were found closer to shore (mean distance from shore 416 feet) than females (793 feet from shore). Two fish were relatively sedentary following spawning, while two fish were more nomadic. Walleye habitat utilization and movement patterns in Otsego Lake differed from that observed in shallow, warm-water lakes and reservoirs.
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