Claytor Lake Research Articles

Locals, tourists, and water recreation issues at Claytor Lake, Virginia

Claytor Lake is a 4,500 acre impoundment of the New River, located in southwestern Virginia and is ideal for pleasure boating, fishing, swimming, and exploration. In fall 2020 a visitor survey was administered to capture boater and adjacent landowner perceptions of the recreation experience, identify safety concerns, and help managers to informed decisions. Almost 200 surveys were collected over a month of data collection. Results indicate that respondents tend to be a dichotomous group of “locals” who live on or within a mile of the lake, and “tourists” who travel greater than 50 miles to visit the lake. Additionally, these two groups access the lake differently through either private docks and launches, or public launch sites and the state park, which further complicates water recreation management action on the lake. Respondents also indicated significantly higher “negative experiences” with PWC and Wake Surf boats. Of these user groups, it appears that more frequent users of the lake were the ones to report more issues with PWC and wake surf boats. Additionally, waterfront owners or those living within one mile of the lake reported the highest levels of concern around wake surf and PWC users. Finally, issues of concern varied across different user groups, and there were issues reported with safety and crowding, which also varied across user groups. These results are valuable highlights of how user type and distance from a site can influence interests, and concerns, and may therefore be an important component for recreation site manager outreach and collaborative planning efforts. Recommendations include outreach, education, and more cross-contextual communication between user groups and adjacent landowners.

Multirotor-assisted measurements of wind-induced drift of irregularly shaped objects in aquatic environments

Ocean hazardous spills and search and rescue incidents are becoming more prevalent as maritime activities increase across all sectors of society. However, emergency response time remains a factor due to the lack of information available to accurately forecast the location of small objects. Existing drifting characterization techniques are limited to objects whose drifting properties are not affected by on-board wind and surface current sensors. To address this challenge, we study the application of multirotor small unmanned aerial systems (sUAS), and embedded navigation technology, for on-demand wind velocity and surface flow measurements to characterize drifting properties of small objects. An off-the-shelf quadrotor sUAS was used to measure the speed and direction of the wind field at 10 m above surface level near a drifting object. We also leveraged sUAS-grade attitude and heading reference systems and GPS antennas to build water-proof tracking modules that recorded the position and orientation, as well of translational and rotational velocities, of objects drifting in water. The quadrotor and water-proof tracking modules were deployed during field experiments conducted in Claytor Lake, Virginia and the Atlantic Ocean south of Martha’s Vineyard, Massachusetts to characterize the leeway parameters of manikins that simulated a person in water. Leeway parameters were found to be an order of magnitude within previous estimates that were derived using conventional wind and surface current observations. We also determined that multirotor sUAS and water-proof tracking modules can provide accurate and high-resolution ambient information that is critical to understand how changes in orientation affect the downwind displacement and jibing characteristics of small objects floating in water. These findings support further development and application of multirotor sUAS technology for leeway characterization and understanding the effect of an object’s downwind-relative orientation on its drifting characteristics.

Exploring the Relationship between Fishing Regulations and Angler Compliance in Virginia

Fishing regulations are often complex and reliant upon a general understanding of geographical awareness. Fishing regulations for the same fish species can vary across neighboring waterways or along a single waterway that is delineated into a river and lake, for example. It is plausible that anglers may not understand these complex regulations and subsequently may act in non-compliance. The purpose of this study was to explore the relationship between fishing regulations and angler compliance on the New River and Claytor Lake in Virginia. A survey was used to collect data from a sample of 15,000 registered Virginia freshwater anglers from July 2016-September 2017. Both anglers’ regulatory knowledge and several demographic variables were used to predict the likelihood of anglers’ compliance using a regression analysis. The potential policy implications of this research may include an increase in attention for angler education programs and discretionary tactics by law enforcement.

Movement, habitat use, and survival of juvenile grass carp in an Appalachian reservoir

Grass carp Ctenopharyngodon idella have been widely introduced in aquatic ecosystems to combat outbreaks of problem aquatic plants. However, the extent to which introduced carp stray from intended habitats and ecosystems is frequently unevaluated. Grass carp were stocked into a temperate riverine and montane reservoir (Claytor Lake, VA USA) to control a rapidly spreading Hydrilla verticillata infestation. Fish introductions sparked concern that grass carp might exit the reservoir and impact adjacent river ecosystems and native plants. We conducted a 2-y telemetry study concurrent with annual grass carp stockings in Claytor Lake to investigate migration potential, habitat use, and annual survival of recently introduced grass carp. We radio-tagged 34 and 45 juvenile grass carp in 2011 and 2012, respectively. In both years, grass carp movements were highest during the first month post-stocking and declined dramatically thereafter, presumably due to carp settling in areas with high hydrilla biomass. Only 3% of radio-tagged grass carp exited the reservoir upriver over the study period. Statistical modeling indicated grass carp movements were driven largely by temperature, while other climatic (e.g., wind speed and barometric pressure) and habitat variables (depth, vegetation coverage) were occasionally also important. Year-1 survival of grass carp was 44% for the 2011 cohort, and 25% for the 2012 cohort. Even though young grass carp did not express an inclination for out-reservoir migrations during the study, these patterns may change as fish approach sexual maturity, hydrilla coverage declines, and divergent climate variations occur. We recommend managers continue monitoring grass carp movements alongside changes to the spatial and temporal dynamics of hydrilla in the reservoir over time.

Occurrence of Two Non-indigenous Catostomid Fishes in the New River, Virginia

Two catostomid fishes, Carpiodes cyprinus (Quillback) and Moxostoma collapsum (Notchlip Redhorse), were recently discovered in the New River watershed (Ohio River basin) in Virginia. The New River fish fauna is naturally depauperate relative to surrounding watersheds, and it has been altered substantially due to non-indigenous species introductions. Notchlip Redhorse and Quillback are established in Claytor Lake and are dispersing into novel reaches of the mainstem New River. We suspect that these species became established following bait-bucket introductions or incidentally during game-fish stockings. Public education, policy changes, and stricter hatchery procedures are needed to minimize such occurrences of non-indigenous species introductions.

Friction angles at sandy beaches from remote imagery

The rigour of extracting friction angles, and eventually lower-bound bearing strength, in sandy beach settings through slope angles determined from digital images (visual spectrum) is explored. Digital images of topographic sand features using hand-held cameras, an unmanned aerial vehicle and a panchromatic satellite sensor are analysed to determine average slope angles using three-dimensional reconstruction. Greyscale gradients and shadows are utilised in the satellite images to extract slope estimates. The slope angles matched tilt table results of samples from the same locations at the Duck, NC, and Claytor Lake, VA, field sites. Direct shear testing of sample material suggest friction angles of ∼33° and ∼35°, respectively. The authors test a potential pathway to derive lower-bound bearing strength using these remotely sensed slope angles. Preliminary results are encouraging, but likely sensitive to the impact of moisture content, differences between the maximum and the observed slope angle and internal friction angles.

Diversity and Abundance of Ice Nucleating Strains of Pseudomonas syringae in a Freshwater Lake in Virginia, USA.

The bacterium Pseudomonas syringae is found in a variety of terrestrial and aquatic environments. Some strains of P. syringae express an ice nucleation protein (hereafter referred to as Ice+) allowing them to catalyze the heterogeneous freezing of water. Though P. syringae has been sampled intensively from freshwater sources in France, little is known about the genetic diversity of P. syringae in natural aquatic habitats in North America. We collected samples of freshwater from three different depths in Claytor Lake, Virginia, USA between November 2015 and June 2016. Samples were plated on non-selective medium (TSA) and on medium selective for Pseudomonas (KBC) and closely related species to estimate the total number of culturable bacteria and of Pseudomonas, respectively. A droplet freezing assay was used to screen colonies for the Ice+ phenotype. Ice+ colonies were then molecularly identified based on the cts (citrate synthase) gene and the 16S rDNA gene. Phylogenetic analysis of cts sequences showed a surprising diversity of phylogenetic subgroups of P. syringae. Frequencies of Ice+ isolates on P. syringae selective medium ranged from 0 to 15% per sample with the highest frequency being found in spring. Our work shows that freshwater lakes can be a significant reservoir of Ice+ P. syringae. Future work is needed to determine the contribution of P. syringae from freshwater lakes to the P. syringae populations present in the atmosphere and on plants and, in particular, if freshwater lakes could be an inoculum source of P. syringae-caused plant disease outbreaks.

A Survey of the New River Aquatic Plant Community in Response to Recent Triploid Grass Carp Introductions into Claytor Lake, Virginia

Abstract Aquatic plant communities play critical roles in the form and function of stream ecosystems. In this study, we surveyed the aquatic-plant community along a 39-km reach of the New River, VA, in response to triploid Ctenopharyngodon idella (Grass Carp) stockings to control Hydrilla verticillata (Hydrilla) in Claytor Lake. We utilized drift-net sampling methods and visual observations to document the current plant community in this reach. Nine of 12 aquatic plant species identified in our survey have been documented as preferred forage for Grass Carp. These findings may indicate that migrating Grass Carp could alter the plant community in this reach. We recommend continued monitoring of this system to characterize any future effects of Grass Carp herbivory.

Comparing discontinuity orientation data collected by terrestrial LiDAR and transit compass methods

Terrestrial LiDAR (light detection and ranging) and a transit compass were used separately to collect discontinuity orientation data at an abandoned quarry in the vicinity of Claytor Lake Dam, southwest of Christiansburg, Virginia. DIPS software program was used to process the data obtained by the two methods. Stereonet plots of orientation data, generated by the DIPS program, were used to determine the principal discontinuity sets present at the quarry. Statistics provided by the DIPS program were compared to evaluate the variability of discontinuity orientation data between the two methods. The purpose was to evaluate the reliability of LiDAR-derived data, by comparing it with manually collected data, and to investigate whether the two datasets yield similar discontinuity orientations. Results of the study show that both data sets are able to identify bedding and two other joint sets. However, one gently dipping joint set, identified by the manually collected data, is either under-represented or missing from the LiDAR data. Possible factors influencing this difference in the two datasets include: (1) shadow zone (related to sampling bias), (2) patch size, and (3) spatial variation of discontinuity orientations. We suggest a protocol for minimizing the influence of these factors on discontinuity mapping by the LiDAR method.

Movements of Walleyes in Claytor Lake and the Upper New River, Virginia, Indicate Distinct Lake and River Populations

AbstractInference 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.

Importance of Reservoir Inflow in Determining White Bass Year-Class Strength in Three Virginia Reservoirs

Abstract The relationship between spring inflows and the year-class strength of white bass Morone chrysops was examined in three main-stem Virginia reservoirs. The catch of age-1 white bass in fall gill-net samples from 1980 to 1998 was used as an index for year-class strength in Claytor Lake and Kerr Reservoir. Claytor Lake was sampled by electrofishing during the spring spawning run in 1996, and the residuals associated with catch-curve regressions were computed to estimate year-class strength. In Leesville Reservoir, white bass recruit to gill nets at age-0; therefore, the catch per effort of age-0 white bass was used as an indicator of year-class strength. Strong year-classes (≥0.03 fish/9.29 m2 of gill net) were rare in each reservoir. In Claytor Lake, strong year-classes were produced in 1987 and 1993, both years of high spring inflows. Lake inflows during April were also positively related to the year-class strength of white bass in Kerr and Leesville reservoirs and explained about 90% of the varia...

Epidemiology of Infection by Nontuberculous Mycobacteria:Mycobacterium avium, Mycobacterium intracellulare, andMycobacterium scrofulaceumin Acid, Brown-Water Swamps of the Southeastern United States and Their Association with Environmental Variables

Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum (MAIS) organisms were isolated and identified from waters, soils, aerosols, and droplets ejected from water collected from four geographically separate aquatic environments (Okefenokee Swamp, GA; Dismal Swamp, VA; Claytor Lake, VA; and Cranberry Glades, WV) during several seasons. Recovery of MAIS was significantly higher from waters, soils, and aerosols collected from the two acid, brown-water swamps located in the southeastern coastal plain. High MAIS numbers correlated with warmer temperature, low pH, low dissolved oxygen, high soluble zinc, high humic acid, and high fulvic acid. This research, in relation to previous findings for the geographic distribution and physiologic ecology of MAIS, supports the conclusion that waters, soils, and aerosols of the acid, brown-water swamps of the southeastern United States coastal plain represent major environmental sources likely connected with the higher incidence of human infection in this region.

Seasonal Dynamics and Size Structure of Littoral Cladocera in Claytor Lake, Virginia

ABSTRACT Seasonal changes in species dominance and size structure of littoral Cladocera were investigated in a mainstream reservoir in southwest Virginia. Twenty-four species of benthic, vegetation-dwelling, and pelagic cladocerans were captured during the study. The assemblage was dominated numerically by small Bosmina and Chydorus, while larger vegetation-dwelling species such as Alona, Eurycercus, Latona, and Sida typically accounted for the majority of biomass. The number of species captured was relatively constant from May through November with decreasing dominance as the season progressed. Seasonal dynamics of individual species resulted in significant shifts in frequency distributions of numbers and volume across size classes. Overall, the assemblage was divided seasonally as dominance shifted from pelagic to vegetation-dwelling species in mid-July.

Use of Genetic Tags to Evaluate Stocking Success for Reservoir Walleyes

Abstract In recent years, recruitment of walleyes Stizostedion vitreum vitreum in Claytor Lake, Virginia, has resulted from both natural reproduction and periodic stockings of age-0 fish from the midwestern United States. Malate dehydrogenase (MDH) allele frequencies of six walleye cohorts were assessed by starch gel electrophoresis. Augmented cohorts were found to possess MDH allele frequencies significantly different from unstocked cohorts, and both augmented and unstocked cohorts differed in allele frequencies from the juvenile fish that had been stocked during that period. Success of supplemental stocking was evaluated by quantifying shifts in cohort allele frequencies due to the stocking of juvenile fish with allele frequencies different from resident fish. Supplemental stocking of juvenile walleyes contributed an average 67% of year-class strength to augmented cohorts in Claytor Lake during 1976–1979. This investigation demonstrates the utility of genetic tags for evaluating stocking efficiency, eve...

Reproduction and Early-Life Accommodations of Landlocked Alewives to a Southern Range Extension

Reproduction and first-year growth and food habits of landlocked alewives Alosa pseudoharengus in Claytor Lake, Virginia were examined and compared to descriptions for populations in the speciesˈ established New England-Great Lakes range. Alewives in mesothermal (2–27 C) Claytor Lake are shorter-lived (3 years) but grow faster, mature earlier (age 1), and have higher relative and absolute fecundities than have been reported for populations in colder northern waters. The 1979 spawning period extended from early May to early August, beginning at least 1 month earlier and lasting 4–9 weeks longer than in northern lakes. Changes in ovary condition during the spawning period suggest that alewives may be fractional spawners. Evidence of spawning was found in littoral areas throughout the lower 15 km of the reservoir. Growth in length of age-0 Claytor Lake alewives was linear through September and terminated in late autumn. Total first-year growth was reduced in 1979 (maximum of 130 mm total length, TL) from previous years (average of 160 mm TL), although it was substantially greater than recorded in the Great Lakes and the northeastern United States. The longer growing season, rather than accelerated in-season growth, appears to account for larger size achieved in Claytor Lake. High annual growth limits predation by Claytor Lake game fish on early spawned age-0 alewives by late summer. As elsewhere, larval and juvenile alewives (6–70 mm TL) fed primarily on copepods and cladocerans. Age-0 alewives longer than 35 mm TL demonstrated positive size-selection for cyclopoid copepods comparable to that shown by adults. Our findings suggest that self-sustaining alewife populations can be established in many inland waters but raise concerns regarding their forage value and community impacts.

A comparison of methods for quantitative analysis of feeding selection of fishes

Predator-prey data were obtained in a study of feeding ecology of land-locked alewife,Alosa pseudoharengus, in Claytor Lake, Virginia, and subjected to two indices of electivity as well as a nonparametric paired-comparisons statistical test. Values obtained from the two indices were often contradictory with each other and the statistical test. Attributes of the statistical procedure render it more appropriate than electivity indices to describe feeding selectivity in fish populations. Results of the study also demonstrated the importance of considering the size composition of zooplankton populations in prey preference studies; measures of selection were often positive for zooplankters ≥ 1.0 mm while negative for those of the same prey group < 1.0 mm length. Because numerous problems are inherent with in situ feeding selectivity studies of planktivorous fishes, selectivity determinations, regardless of methodology, should be construed in a relative rather than absolute context.

Cheilanthes feei New to Virginia

The Slender Lip Fern, Cheilanthes feei Moore, is a widely distributed species of the western United States which occurs eastward to Arkansas, Missouri, Kentucky, and Illinois (Fernald, 1950; Steyermark, 1963; Cranfill, 1980; Mohlenbrock, 1967). The easternmost station for this fern was along Cedar Creek in Bullitt County, Kentucky, in a region known as The Knobs. This small population, discovered originally by Clyde Reed (Reed, 1952), is thought to be disjunct from the next nearest stations along the Ohio River in southern Illinois (Cranfill, 1980). Cheilanthes feei was discovered in 1979 by Bentley during a routine survey of the plants of Claytor Lake State Park, Pulaski County, Virginia. The actual identity of the plant went unknown until the station was visited by the authors on May 8, 1981, when the first voucher collections were made. This discovery is a remarkable disjunction of approximately 450 km eastward from the Bullitt County, Kentucky station and nearly 650 km from the more contiguous portion of its range from Illinois westward. The preferred habitats of this fern are dry, exposed crevices in limestone or dolomite cliffs (Wherry, 1961; Mohlenbrock, 1967). Extensive exposures of this kind may be found along the New River in Virginia. Claytor Lake is a large impoundment of some 4500 acres formed in 1939 when the Appalachian Power Company built its Claytor Dam on the New River just upstream of Radford, Montgomery County, Virginia. In the southeastern sector of Pulaski County, the New River is deeply entrenched where it has cut through thick beds of limestone of the Rome formation and Elbrook dolomite, both of Cambrian origin. The more resistant dolomite forms nearly vertical cliffs, frequently several hundred feet high. The station for C. feei is a rather small but precipitous cliff, perhaps fifty feet high, which forms a nose-like projection along a westward facing portion of the shoreline. Because of the configuration of the rock, the exposures range from northwestern to southern. During a second visit to the outcrop on May 14, 1981, an estimate of 1200 plants was made. Most of these are extremely small and occupy nearly every minute fracture in the rock. Several hundred larger, mature plants crowd the deeper cracks and more protected, overhanging sites. Several smaller, shaded outcrops in oak woods adjacent to the main cliff support a considerable number of additional plants. Adjacent areas of the lake shore, where similar outcrops and exposures occur, were searched for additional populations of C. feei, but only six other plants were found on a very small ledge at the water level several hundred feet to the north. Since the normal pool elevation is approximately eighty-feet above the former river level, this same outcrop was undoubtedly much more extensive prior to flooding. A much larger population may have existed and, of course, other nearby populations may have been inundated by the lake waters.

Consequences of an Alewife Die-off to Fish and Zooplankton in a Reservoir

Alewife Alosa pseudoharengus was the principal pelagic forage species in Claytor Lake, Virginia, prior to a severe die-off in the winter of 1977–1978. Due to successful reproduction in 1978, abundance of adult alewives rebounded sharply in 1979. Changes in the size structure of the zooplankton community between summer 1978 (larger) and 1979 (smaller) were similar to differences reported for other waters between periods of low and high alewife abundance and are attributable to selective alewife predation. Alewife-induced shifts in zooplankton composition toward smaller forms represent a potentially significant adverse impact on cohabiting planktivores, including young-of-the-year sport fishes. Alewives seldom were eaten by littoral piscivores (black basses Micropterus spp. and crappies Pomoxis spp.) but were prevalent in the diets of the pelagic species (walleye Stizostedion vitreum vitreum, white bass Morone chrysops, and striped bass Morone saxatilis). When alewives were less abundant during spring and summer of 1978, pelagic predators ate more yellow perch Perca flavescens, crappies, bluegills Lepomis macrochirus, and crayfish Cambarus sp. than in 1979. Growth of adult alewives and young-of-the-year walleyes and white bass was significantly greater in 1978 than in the 2 years preceding the die-off, suggesting that both intra- and interspecific trophic competition operate when alewife density is high. Annual growth of age-2 walleyes and white bass did not differ substantially before and after the die-off; impact of the population collapse may have been mitigated by high reproductive success and rapid first-year growth of alewives in 1978. These findings indicate that alewife size-selective planktivory may have a more enduring and potentially severe impact on the reservoir fishery than does instability in the alewife population.

Piscivority in a Land-Locked Alewife (Alosa pseudoharengus) Population

Larval fish were a frequent dietary component of alewives (Alosa pseudoharengus) from Claytor Lake, Virginia, USA. Alewives consumed the young of four game and two forage species (maximum 26 mm total length (TL)). Alewife piscivority appeared to be at least partially nocturnal and was more prominent in littoral than in limnetic areas. Predator and prey lengths were positively correlated, although morphological limits on larval fish ingestion by alewives were not severe. Peak occurrence (40–70%, June 1978) of larval fish in alewife stomachs coincided with a precipitous decline in zooplankton density. Zooplankton abundance was higher in early summer 1979, when alewife piscivority was less common. Our findings support the hypothesis that alewife piscivority could have contributed to the collapse of Great Lakes resident fish populations following alewife establishment. Alewife piscivority should be considered in risk–benefit evaluations prior to introducing alewife as a pelagic forage species.Key words: alewife, Alosa pseudoharengus; feeding ecology, larval fish, Great Lakes fisheries, forage introductions

Age, Growth, and Utilization of Landlocked Alewives in Claytor Lake Virginia

Age, Growth, and Utilization of Landlocked Alewives in Claytor Lake Virginia