Matthew M. White

ENHANCING PERCID STOCKING SUCCESS BY UNDERSTANDING AGE‐0 PISCIVORE–PREY INTERACTIONS IN RESERVOIRS

Though young-of-year (YOY) saugeyes (Stizostedion vitreum × S. canadense) are routinely stocked in spring to create and maintain percid fisheries, their growth and survival to fall vary greatly among Ohio reservoirs, as well as among years within a reservoir. To understand the relative importance of size-dependent and size-independent mechanisms during ontogeny that underlie variable stocking success of saugeye, we quantified the role of stocking date and prey density (zooplankton and ichthyoplankton, i.e., larval gizzard shad [Dorosoma cepedianum]) in field enclosure, pond, and reservoir experiments. In 1-m3 enclosures, ichthyoplankton density (0, 5, 10, or 20 larval gizzard shad/m3) did not influence time to switch to piscivory by saugeye (all switched in <12 h); saugeye in enclosures with ichthyoplankton, regardless of density, grew faster than those without ichthyoplankton. In 0.4-ha ponds, saugeye growth and survival did not differ between ponds with zooplankton plus macrobenthic prey and ponds with ...

A Genetic Assessment of Ohio River Walleyes

Abstract Walleyes Sander vitreus from nine Ohio River pools were examined by means of two independent restriction fragment length polymorphism (RFLP) analyses of mitochondrial DNA, allozyme analysis of nuclear DNA, and microsatellite analysis of nuclear DNA. The primary objective of this project was to document genetic variation and population structuring in walleyes among the nine pools analyzed. Both RFLP analyses revealed the presence of a distinct haplotype that was most abundant in walleyes collected from two tailwaters in the upper Ohio River (river miles 54 and 84), suggesting a remnant native population. The allozyme analysis also revealed differentiation between walleyes with the two haplotypes, even though there were no fixed differences. The microsatellite analysis indicated highly significant structuring among the nine pools analyzed. A lack of microsatellite differentiation between the two haplotypes detected in the same pool suggests that the fish are freely interbreeding. If the unique hapl...

Structure and Conservation of Tandem Repeats in the Mitochondrial DNA Control Region of the Least Brook Lamprey (Lampetra aepyptera)

Tandemly repeated sequences are a common feature of vertebrate mitochondrial DNA control regions. However, questions still remain about their mode of evolution, function, and phylogenetic distribution. We report phylogenetic and geographic patterns of variation of control region repeat sequence and number in a nonparasitic lamprey, Lampetra aepyptera. A survey of populations from throughout the species’ range revealed remarkably low repeat sequence polymorphism but some interpopulation variation in repeat number. The high sequence similarity extended to repeats observed in other species in the genus Lampetra and other lamprey genera. The very low levels of variation suggest a high copy turnover. Our data are consistent with the illegitimate elongation model of repeat gain and loss and further suggest that repeat change occurs at internal copies. However, the limited variation across some species of lamprey suggests that functional constraints may further limit variation.

Spatial-Genetic Structure in the Eastern Chipmunk, Tamias striatus

Spatial autocorrelation is used to identify the pattern of allozyme variation in populations of the eastern chipmunk ( Tamias striatus ). A nonrandom pattern of autocorrelation was detected when distances several hundred times the distance across an average home range were considered. A population sufficiently large to survey demographics and the mating system (across several dozen home ranges) was deemed too small for genetic studies. The size of the genetic neighborhood of the chipmunk was estimated from a correlogram. These results are interpreted to mean that it is possible to identify the size of the genetic neighborhood by use of spatial autocorrelation and that it is an appropriate preliminary analysis for identifying the limits of dispersal and gene flow.

Biochemcial systematics of the North American Pteronarcys (Pteronarcyidae: Plecoptera)

Abstract Allozyme data from eight species of Pteronarcyidae were used to determine phylogenetic relationhips within the family and genus Pteronarcys . Data were analysed as allele frequency data using the BIOSYS-1 computer package and as discrete characters using the PENNY (parsimony) and MIX (mixed parsimony) options of the PHYLIP computer program. Certain analyses yielded species relationships which are in agreement with phylogenies based upon morphological characters from various life-history stages. Bootstrap confidence limits on phylogenies based on allozyme as well as morphological data are discussed. The age of the family likely contributes to the lack of concordance with previously proposed phylogenies.

Genetic Variation in White Bass

Abstract A protein electrophoretic survey of white bass Morone chrysops was conducted to evaluate the extent and pattern of extant genetic variation and population structuring. Forty-four presumptive structural loci were surveyed from eye, liver, and skeletal muscle tissue from 456 white bass in 19 samples. The level of allelic variation observed within white bass populations was low relative to many other species of fish, but it was consistent with levels of variation observed in the congeneric striped bass M. saxatilis and may represent a feature common to all species in the genus. Significant interpopulation genetic heterogeneity was observed; however, the overall level of differentiation among populations was quite low. Widespread stocking of white bass since 1900 and rapid range expansion could, in part, explain the absence of population structuring that is consistent with geographic proximity or drainage. The high frequencies of an mIDHP* allele in Lake Erie collections that was absent in those from...

An Assessment of Population Structure and Genetic Purity of Sauger in Two High-Elevation Reservoirs in Wyoming

ABSTRACT We studied sauger (Stizostedion canadense) in the only two reservoirs where they occur in Wyoming to determine genetic purity, describe population features, and determine differences from other populations across North American. Electrophoretic analysis did not identify hybridization with walleye (S. vitrium). The sauger were slow growing, long lived, and had low body condition compared to other populations.

Genetic Identity of Walleye in the Cumberland River

Abstract Walleye from the upper Cumberland River drainage were examined by means of mitochondrial DNA restriction fragment length polymorphism (RFLP) analysis, microsatellite analysis of nuclear DNA, and sequencing of the mitochondrial DNA control region. The objectives of this study were to identify native Eastern Highland and introduced Great Lakes walleye and determine if introgression occurs between the two stocks. Additional collections were made from rivers of the Eastern Highlands to establish evolutionary relationships. Native and introduced walleye appear reproductively partitioned in the upper Cumberland River drainage, with natives persisting in the tributary Rockcastle River and introduced Great Lakes walleye reproducing in the Big South Fork of the Cumberland River. Additional partitioning between native and introduced stocks may occur in the Kanawha River, in the Ohio River drainage. Native walleye from the Cumberland River share a common ancestor with others from Eastern Highland rivers but are distantly related to populations from the southern Mobile River basin and the northern Great Lakes.

Mitochondrial DNA Sequence Variation in Saugers

Abstract Despite extensive work documenting genetic variation in walleyes Sander vitreus, relatively little is known about the distribution of variation in saugers S. canadensis. Mitochondrial DNA sequence variation was surveyed among samples of saugers to assess the magnitude and distribution of variation among sauger populations. Sequencing of 847 bases of the mitochondrial DNA control region in 60 individuals yielded 19 haplotypes that differed by 0.1–0.8%. Several haplotypes were broadly distributed across the range sampled. The data support the hypothesis of a single glacial refugium. There was no evidence of multiple refugia within which sauger populations could have differentiated. A single Mississippian refuge is consistent with the data and with likely routes of colonization of the Great Lakes–St. Lawrence River and the Hudson Bay drainage. A mismatch distribution analysis among haplotypes suggested a recent population expansion; the presence of haplotypes with broad distributions is also consist...

Mitochondrial DNA Variation in the Endangered Colorado Pikeminnow: A Comparison among Hatchery Stocks and Historic Specimens

Abstract The Colorado pikeminnow Ptychocheilus lucius is a federally endangered species restricted to the Colorado River. Dexter National Fish Hatchery and Technology Center, Dexter, New Mexico, maintains three separate captive stocks of the Colorado pikeminnow: 1974YC (Yampa River), 1981YC (Green–Colorado rivers), and 1991YC (Colorado River). We surveyed mitochondrial DNA diversity in these three stocks (879 base pairs [bp]; ND-4L and ND-4 genes; N = 30) and in museum specimens collected from 1890 to 1976 (450 bp; ND-4; N = 11). All individuals had the same haplotype except for a 1-bp variant detected in 2 of the 12 fish from 1981YC. The low variation is postulated to be the result of a post-Pleistocene bottleneck in the wild and small sizes of the hatchery founder populations.