Nocomis Micropogon Research Articles

A flooded future for River Chub? Future impacts of climate change and urbanization on reproduction of a keystone native fish species

AbstractObjectivePredicted impacts of climate change in the eastern United States are pervasive and complex, including increased precipitation, increased frequency of heavy precipitation events, and altered seasonality of rainfall. This will potentially lead to increased flooding frequency and severity. The River Chub Nocomis micropogon is an important keystone and engineer species in the eastern United States, primarily through its construction of nesting habitat, which is shared with other species (“nest associates”) in a mutualistic relationship. River Chub nests are vulnerable to high flows caused by excessive precipitation and by urbanization of watersheds. Using predictions of climate change models, we examined the potential for increased River Chub nest disruption under two climate change scenarios.MethodsPublished thresholds linking River Chub nest disruption with stream discharge were used to interpret fine‐scale predictions of a downscaled climate prediction model (HadGEM2‐ES) using a stochastic weather generator (LARS‐WG6) calibrated to two climate change scenarios. This was examined for a case study watershed (Big Elk Creek, Maryland). The amount of River Chub nest disruption was compared between present‐day stream discharge observations (1995–2021) and simulated data for 2061–2080 under the “worst case” (RCP85) and “probable‐case” (RCP45) scenarios. Potential nest disruption in an urbanized stream that lost its River Chub (Gwynns Falls, Maryland) was also evaluated for comparison with Big Elk Creek scenarios.ResultSignificantly elevated nest disruption under both RCP45 and RCP85 relative to observed current conditions was found under status quo watershed characteristics in the form of more disruptive events, more disrupted days, and shorter periods of disruption‐free days during the River Chub nesting season. Potential nest disruption in the urbanized case study stream was far greater than that observed for any scenario.ConclusionIncreased nest disruption projected by the downscaled HadGEM2‐ES climate prediction model was moderate and far below the level of nest disruption observed in flashy urbanized streams that have lost or may have lost River Chub populations in the region. The moderate impacts of increased flooding from climate change will interact with projected population growth and urbanization for the Big Elk Creek watershed. Mechanistic modeling of fine‐scale processes by using stochastic weather generators shows promise for modeling the responses of ecosystems to changing conditions.

Rapid Molecular Determination of Sex for Western North American Chub (Gila spp.)

AbstractGathering sex data is frequently a complicated matter for fish species that lack sexually dimorphic traits. Secondary sexual characteristics are cryptic or nonexistent in many minnows (Cyprinidae) during early life stages or outside of the breeding season, which may require lethal methods for determining sex. This complicates many conservation actions and population genetic studies, including (1) the development of hatchery broodstocks for threatened and endangered species, (2) sex ratio determination in wild populations, (3) the influence of sex ratio on the effective population size estimates, and (4) limitations on the implementation of genetic tagging and parentage assignment in wild populations. Here, we remedy this issue for four western North American chub species (Gila spp.) through restriction‐site‐associated DNA sequencing of Bonytail G. elegans, which identified a single locus indicating an XY sex determination system and no candidate loci consistent with a WZ system. This locus cross‐amplified in three additional Gila species (Chihuahua Chub G. nigrescens, Virgin Chub G. seminuda, and White River Chub G. jordani), although species‐specific differences necessitated the development of three novel primer/probe sets. Real‐time PCR with hydrolysis probe assays was used to genotype sex‐linked single‐nucleotide polymorphisms for each species. The measurement of endpoint fluorescence in a real‐time PCR thermal cycler allowed for rapid and accurate sex genotyping of these species, with accuracy >97% relative to phenotypic sex identification when three PCR replicates were employed. These assays provided high precision, with unanimous results across >87% of the replicates and a majority consensus genotype for 98.6% of the samples. The locus identified herein was conserved across all of the Gila species that we tested (n = 6) and other western North American cyprinids; however, sex‐linked polymorphisms were found only in the four species that are named above. Consequently, this locus has promise for the identification and development of sex‐linked assays for other Gila and closely related cyprinids.

Fish life history trends indicate increasing flow stochasticity in an unregulated river

AbstractLife history theory provides a framework to understand environmental change based on species traits that capitalize on stable, predictable, or stochastic environmental conditions. We evaluated life history strategies and temporal trends in abundance from 1975 to 2017 for 28 fish species within the Potomac River of eastern North America. Multivariate analysis identified life history strategies defined by small‐bodied species with extended spawning seasons and early maturation (opportunistic strategists), large‐bodied species with delayed maturation and long lifespans (periodic strategists), and intermediate‐sized species exhibiting parental care (equilibrium strategists). Linear mixed models detected temporal trends in abundance for 13 species (46%), of which nine increased and four decreased over time. Increasing species were characterized by opportunistic life history strategies (e.g., banded killifish, Fundulus diaphanous; mosquito fish, Gambusia holbrooki), whereas decreasing species were characterized by periodic or equilibrium strategies (e.g., smallmouth bass, Micropterus dolomieu; river chub, Nocomis micropogon). Recent introductions can account for temporal increases in some cases, but most increasing species are native to the study area. Observed increases in opportunistic native species and decreases in periodic and equilibrium species indicate that environmental conditions have become less stable and less predictable over time, consistent with observed increases in spring peak flows in the study area. Our study indicates the importance of environmental stochasticity for fish community responses to land use and climate change and demonstrates the utility of life history theory in this regard.

Report on the Short-Term Scavenging of Decomposing Native and Non-Native Trout in Appalachian Streams

Trout fishing is one of the primary recreational activities in the southern Appalachians, with large amounts of fish stocked on a regular basis. However, very little is known regarding the fate of hatchery reared carcasses not captured by anglers, representing a likely important ecological resource to local communities. We tested the efficacy of underwater video to characterize short term decomposition and consumption by aquatic scavengers of native brook and non-native rainbow trout, Salvelinus fontinalis and Oncorhychus mykiss. This study took place on the Cherokee Qualla Boundary in North Carolina, a location with one of the highest riverine stocked trout densities in the eastern United States. During May 2017, 10 waterproof cameras were deployed for 1-hour intervals on each carcass twice daily for a period of 5 days. We observed that 75.3% of recorded video contained river chub, Nocomis micropogon, with only 24.7% visited by crayfish, with a maximum of 9 and a mean of 1.93 for N. micropogon. Half of the carcasses were removed within 2 days. Based on natural history evidence and some trail cameras, we believe that otters were removing carcasses. Otters showed no preference for either trout species. Underwater video allowed us to characterize initial decomposition within stream diurnal scavengers in a short period using a visual, non-destructive low-cost method. Future studies should monitor large mammalian scavengers to further elucidate the role of fish stocking on aquatic communities.

Disturbance-driven changes in fish assemblages caused by a sudden increase in salinity in a perennial desert stream

Disturbance is a key factor in structuring fish assemblages in rivers; characterizing reactions to disturbance is especially important in systems containing endangered species due to their vulnerability to extinction. A natural disturbance event occurred in the Virgin River in 1985, when normal flow patterns changed due to the appearance of a sinkhole upstream of the hot saline Pah Tempe Springs. This led to abnormally elevated levels of temperature and salinity that propagated downstream. We examined changes in fish assemblages at five sites in a 21 km reach downstream from the hot springs in the mainstem Virgin River, which were monitored monthly (with the exception of 1 site monitored biannually) between 1984 and 1987. Specifically, we compared the responses of the different fish species in space and time. Of the six native species investigated, speckled dace, spinedace, and the endangered woundfin experienced declines in abundance at sites closest to the disturbance. In contrast, Virgin River chub, another endangered species, experienced increases in abundance in sites nearest the disturbance, and desert sucker and flannelmouth sucker showed no change. Redundancy analysis confirmed that changes in assemblage structure were significant. Differential responses to the disturbance appeared to correlate with differences in feeding ecology, with insectivores being the most affected group. In terms of recovery, species with higher abundances in neighboring sites experienced faster recoveries than those with lower abundances. This study characterizes disturbance reactions in the Virgin River, and emphasizes the susceptibility of rare species to natural disturbances and subsequent depression of recolonization rates.

Predicting impacts of urbanized stream processes on biota: high flows and river chub (Nocomis micropogon) nesting activity

This study quantified the impact of high stream flows on reproductive activities of river chub (Nocomis micropogon). Using observed relationships between flow and reproductive activities, the number of predicted damaging flow events was compared between streams with extant river chub populations and urbanized streams. Monitoring the survivorship of river chub nests during 2013–2014 (N = 101) revealed consistent relationships between interval peak flow measured at flow gauges and the integrity of river chub nests within sites. Flow-mediated disruption of nests was frequent, and interval peak flows were significantly correlated with nest erosion rates. Logistic regression between fate of river chub nests and standardized peak flow (Qs) during monitoring intervals identified thresholds of peak flow corresponding to complete and partial destruction of river chub nests. Observed thresholds were used to predict the frequency of potentially damaging flows in urbanized versus river chub study streams, based on archival flow monitoring data. Repeated measures analysis revealed that the frequency of flows predicted to result in the loss of all nests was significantly higher in urbanized streams (F = 122.2; df = 1; P < 0.001 ). While key life history information needs to be determined to fully understand the impacts of high flows on river chub population dynamics, results indicate the disruption of nests through frequent high flows as a mechanism for the reduction of this important species in urbanized areas. Improved understanding of the interactions between stream processes and biota will aid in the design of specific stream protection and restoration strategies.

Sampling Characteristics and Calibration of Snorkel Counts to Estimate Stream Fish Populations

AbstractSnorkeling is a versatile technique for estimating lotic fish population characteristics; however, few investigators have evaluated its accuracy at population or assemblage levels. We evaluated the accuracy of snorkeling using prepositioned areal electrofishing (PAE) for estimating fish populations in a medium‐sized Appalachian Mountain river during fall 2008 and summer 2009. Strip‐transect snorkel counts were calibrated with PAE counts in identical locations among macrohabitats, fish species or taxa, and seasons. Mean snorkeling efficiency (i.e., the proportion of individuals counted from the true population) among all taxa and seasons was 14.7% (SE, 2.5%), and the highest efficiencies were for River Chub Nocomis micropogon at 21.1% (SE, 5.9%), Central Stoneroller Campostoma anomalum at 20.3% (SE, 9.6%), and darters (Percidae) at 17.1% (SE, 3.7%), whereas efficiencies were lower for shiners (Notropis spp., Cyprinella spp., Luxilus spp.) at 8.2% (SE, 2.2%) and suckers (Catostomidae) at 6.6% (SE, 3.2%). Macrohabitat type, fish taxon, or sampling season did not significantly explain variance in snorkeling efficiency. Mean snorkeling detection probability (i.e., probability of detecting at least one individual of a taxon) among fish taxa and seasons was 58.4% (SE, 6.1%). We applied the efficiencies from our calibration study to adjust snorkel counts from an intensive snorkeling survey conducted in a nearby reach. Total fish density estimates from strip‐transect counts adjusted for snorkeling efficiency were 7,288 fish/ha (SE, 1,564) during summer and 15,805 fish/ha (SE, 4,947) during fall. Precision of fish density estimates is influenced by variation in snorkeling efficiency and sample size and may be increased with additional sampling effort. These results demonstrate the sampling properties and utility of snorkeling to characterize lotic fish assemblages with acceptable efficiency and detection probability, less effort, and no mortality, compared with traditional sampling methods.Received April 29, 2014; accepted July 23, 2014

Predicting Ecological Effects of Watershed-Wide Rain Garden Implementation Using a Low-Cost Methodology

Stormwater control measures (SCMs) have been employed to mitigate peak flows and pollutants associated with watershed urbanization. Downstream ecological effects caused by the implementation of SCMs are largely unknown, especially at the watershed scale. Knowledge of these effects could help with setting goals for and targeting locations of local restoration efforts. Unfortunately, studies such as these typically require a high level of time and effort for the investigating party, of which resources are often limited. This study proposes a low-cost investigation method for the prediction of ecological effects on the watershed scale with the implementation of rain garden systems by using publicly available data and software. For demonstration purposes, a typical urban watershed was modeled using Storm Water Management Model (SWMM) 5.0. Forty-five models were developed in which the percent impervious area was varied 3 to 80%, and the fraction of rain gardens implemented with respect to the number of structures was varied from 0 to 100%. The river chub fish (Nocomis micropogon) and its congeners (Nocomis spp.) were chosen as ecological indicators, as they are considered to be keystone species through interspecific nesting association. Depth and velocity criteria for successful nest building locations of the river chub were determined; these criteria can then be applied to many other watersheds. In this study, both base flow conditions and a typical summer storm event (1.3 cm, 6 h duration) were evaluated. During the simulated storm, nest-building locations were not affected in the 3 and 5% impervious cover models. Nest destruction was found to occur in approximately 54% of the original nest building sites for the 9% and 10% impervious areas. Nearly all of the nest-building locations were uninhabitable for impervious areas 20% and greater. Rain garden implementation significantly improved river chub habitat in the simulation, with greatest marginal benefit at lower levels of implementation.

Temporal Stability Patterns in Fish Species Richness, Diversity, and Evenness in Otter Creek, Vigo County, IN

We used abundance data from fish-population studies (1962–2010) on Otter Creek at Markle's Dam, Vigo County, IN, to examine temporal variation in stream-fish assemblages. Species-richness variation showed a declining trend during the 50 year study period with a mean of 49 ± 8.8 species per decade (range = 39–62 species). Cumulative study species richness comprised 76 fish species with a mean of 21.3 ± 6.1 species collected per sampling event. Dominant species, based on relative abundance during the 50 year period, included Cyprinella spiloptera (Spotfin Shiner), Pimephales notatus (Bluntnose Minnow), Hybognathus nuchalis (Mississippi Silvery Minnow), and Luxilus chrysocephalus (Striped Shiner). Relative abundance of Spotfin Shiner showed an increasing trend during the 50-year study period, whereas Bluntnose Minnow relative abundance showed a decreasing trend. Cumulative frequency-distribution of species richness normalized by decade showed no significant difference, with the exception of the 1970s, which showed a steep decline in the number of species. Repeated-measures analysis of variance showed no significant differences in species diversity (H') or evenness (Pielou's J) over the 5-decade study period. Eleven cool-water species including Chrosomus erythrogaster (Southern Redbelly Dace), Perca flavescens (Yellow Perch), Catostomus commersonii (White Sucker), and Ambloplites rupestris (Rock Bass), and lithophilic spawning species such as Nocomis micropogon (River Chub) and Hybopsis amblops (Bigeye Chub) were extirpated during the study period. Potential changes in sedimentation and thermal gradients may have contributed to these observed extirpations.

Invasive rainbow trout affect habitat use, feeding efficiency, and spatial organization of warpaint shiners

Rainbow trout have been introduced to six of the seven continents and currently are widely stocked for sport fishing. Despite their broad distribution, outside of New Zealand, little is known about the effects of rainbow trout on native species, especially fishes. We conducted experiments in an artificial stream to assess hypotheses that stocked rainbow trout significantly affected: (1) mesohabitat use, (2) foraging success, (3) social behavior, and (4) spatial organization of warpaint shiners (Luxilus coccogenis) a common native minnow found in southern Appalachian streams, with similar patterns of microhabitat use to rainbow trout. We replicated experiments at high and low natural densities (two and five warpaint shiners) and spring/fall (12 °C) and summer (17 °C) temperatures. Treatments included: (1) a control (five warpaint shiners), (2) trout (five warpaint shiners and one rainbow trout), (3) large fish control (five warpaint shiners and one river chub) and (4) density control (six warpaint shiners). The presence of rainbow trout produced a shift by warpaint shiners from pool mesohabitats to shallower, higher velocity habitats with more variable substrata, as well as reduced prey capture success, feeding efficiency, and distance from the front of the tank (i.e., warpaint shiners moved closer to food release points), and increased the distance to the additional fish (i.e., avoidance of the rainbow trout). Negative effects on foraging behaviors were stronger in 12 °C treatments. In a realistic stream flume the presence of rainbow trout produced effects that likely influenced individual fitness of warpaint shiners. The potential effects of stocking rainbow trout on native non-game fishes, such as warpaint shiners should be assessed when implementing or evaluating stocking programs.

Nesting habitat use by river chubs in a hydrologically variable Appalachian tailwater

AbstractAs hydrologic alteration continues to affect aquatic biodiversity, knowledge of the spawning requirements of fishes, especially ‘keystone’ or ‘foundation’ species, is critical for conservation and management. The objectives of this study were to quantify the spawning micro‐ and mesohabitat use of river chub Nocomis micropogon, a gravel mound nesting minnow, in a hydrologically regulated river in North Carolina, USA. At the microhabitat scale, substrate sizes on nests were compared with pebble counts in 1‐m2 adjacent quadrats. Average depths and current velocities at nests were compared with measurements from paired transects. At the mesohabitat scale, generalised linear mixed models (GLMMs) were used to identify the importance of average bed slope, average depth and percentages of rock outcrops (a measure of flow heterogeneity and velocity shelters) for predicting nest presence and abundance. To relate nesting activities to hydrologic alteration from dam operation, nest dimensions were measured before and after a scheduled discharge event approximately six times that of base flow. Additionally, linear regression was used to predict changes in the use of flow refugia and overhead cover with increased fluvial distance from the dam. Microhabitats in which nests were placed had, on average, slower current velocities and shallower depths. Gravel diameters of nests were significantly smaller than substrate particles adjacent to nests. GLMMs revealed that mesohabitats with nests were shallower, had more moderate slopes and greater proportions of rock outcrops than mesohabitats without nests. The scheduled discharge event significantly flattened nests. Near the dam, nests were built in close proximity (≤2 m) to velocity shelters; this relationship diminished with distance from the dam. River chubs are spawning habitat specialists. Because multiple species rely on river chub nests for reproduction and food, the needs of this species should be considered when managing instream flows.

Gravel Addition as a Habitat Restoration Technique for Tailwaters

AbstractWe assessed the efficacy of passive gravel addition at forming catostomid spawning habitat under various flow regimes in the Cheoah River, a high‐gradient tailwater river in North Carolina. The purpose was to provide a case study that included recommendations for future applications. A total of 76.3 m3 (162 tons) of washed gravel (10–50 mm) was passively dumped down the streambank and into the channel in four locations. Gravel sites differed in terms of average reach slope, bank slope, and the initial volume of gravel added, which could have influenced gravel entrainment. Maps of gravel movement under various flows suggested that large‐magnitude discharges (≥113 m3/s) caused extensive migration; however, less obvious, smaller discharges (∼28 m3/s) still caused substantial shifting, which may influence the stability of catostomid spawning substrates. Following gravel addition, the proportion of gravel in the streambed was significantly higher at all gravel sites. However, comparisons of sites to reference stream reaches suggested that sand, gravel, and cobble were still extremely deficient. Additionally, the volume of gravel was inadequate to create gravel depths that provided suitable habitat for catostomid spawning. Although periodic, passive gravel additions may take years to provide suitable spawning habitat for some fish species, we found that river chub Nocomis micropogon utilized the newly added gravel for spawning.

Abandoned Mine Drainage in the Swatara Creek Basin, Southern Anthracite Coalfield, Pennsylvania, USA: 1. Stream Water Quality Trends Coinciding with the Return of Fish

Acidic mine drainage (AMD) from legacy anthracite mines has contaminated Swatara Creek in eastern Pennsylvania. Intermittently collected base-flow data for 1959–1986 indicate that fish were absent immediately downstream from the mined area where pH ranged from 3.5 to 7.2 and concentrations of sulfate, dissolved iron, and dissolved aluminum were as high as 250, 2.0, and 4.7 mg/L, respectively. However, in the 1990s, fish returned to upper Swatara Creek, coinciding with the implementation of AMD treatment (limestone drains, limestone diversion wells, limestone sand, constructed wetlands) in the watershed. During 1996–2006, as many as 25 species of fish were identified in the reach downstream from the mined area, with base-flow pH from 5.8 to 7.6 and concentrations of sulfate, dissolved iron, and dissolved aluminum as high as 120, 1.2, and 0.43 mg/L, respectively. Several of the fish taxa are intolerant of pollution and low pH, such as river chub (Nocomis micropogon) and longnose dace (Rhinichthys cataractae). Cold-water species such as brook trout (Salvelinus fontinalis) and warm-water species such as rock bass (Ambloplites rupestris) varied in predominance depending on stream flow and stream temperature. Storm flow data for 1996–2007 indicated pH, alkalinity, and sulfate concentrations decreased as the stream flow and associated storm-runoff component increased, whereas iron and other metal concentrations were poorly correlated with stream flow because of hysteresis effects (greater metal concentrations during rising stage than falling stage). Prior to 1999, pH < 5.0 was recorded during several storm events; however, since the implementation of AMD treatments, pH has been maintained near neutral. Flow-adjusted trends for 1997–2006 indicated significant increases in calcium; decreases in hydrogen ion, dissolved aluminum, dissolved and total manganese, and total iron; and no change in sulfate or dissolved iron in Swatara Creek immediately downstream from the mined area. The increased pH and calcium from limestone in treatment systems can be important for mitigating toxic effects of dissolved metals. Thus, treatment of AMD during the 1990s improved pH buffering, reduced metals transport, and helped to decrease metals toxicity to fish.

Do herbivorous minnows have “plug-flow reactor” guts? Evidence from digestive enzyme activities, gastrointestinal fermentation, and luminal nutrient concentrations

Few investigations have empirically analyzed fish gut function in the context of chemical reactor models. In this study, digestive enzyme activities, levels of gastrointestinal fermentation products [short chain fatty acids (SCFA)], luminal nutrient concentrations, and the mass of gut contents were measured along the digestive tract in herbivorous and carnivorous minnows to ascertain whether their guts function as “plug-flow reactors” (PFRs). Four of the species, Campostoma anomalum, C. ornatum, C. oligolepis, and C. pauciradii, are members of a monophyletic herbivorous clade, whereas the fifth species, Nocomis micropogon, is a carnivore from an adjacent carnivorous clade. In the context of a PFR model, the activities of amylase, trypsin and lipase, and the concentrations of glucose, protein, and lipid were predicted to decrease moving from the proximal to the distal intestine. I found support for this as these enzyme activities and nutrient concentrations generally decreased moving distally along the intestine of the four Campostoma species. Furthermore, gut content mass and the low SCFA concentrations did not change (increase or decrease) along the gut of any species. Combined with a previous investigation suggesting that species of Campostoma have rapid gut throughput rates, the data presented here generally support Campostoma as having guts that function as PFRs. The carnivorous N. micropogon showed some differences in the measured parameters, which were interpreted in the contexts of intake and retention time to suggest that PFR function breaks down in this carnivorous species.

Dietary lipid supplementation affects the body fatty acid composition but not the growth of juvenile river chub,Zacco barbata(Regan)

A feeding trial was conducted to investigate the effects of dietary lipid level on growth and body composition of juvenile river chub, Zacco barbata (Regan). Juvenile river chub with 0.26 g body weight were given five isoenergetic and isonitrogenous purified diets containing 0–20% lipids in 5% increments for 8 weeks. The dietary lipid source was a 1:1 (w/w) mixture of menhaden fish oil and soybean oil. There was no significant difference on weight gain, feed conversion ratio, or protein efficiency ratio, among fish fed different experimental diets (P > 0.05). Body fat contents of both initial fish and fish fed the diet containing 20% dietary lipid were significantly greater than those fed other diets (P < 0.05). The percentage of total n-3 fatty acids in the body lipids of fish at the beginning of the trial was 12.34%. This value decreased to 3.83% by the end of the trial for fish fed a control diet with no supplemented lipid. Similar trends were observed in linoleic acid contents that were 6.11% and 3.09%, respectively, for initial fish and the fish fed the control diet for 8 weeks. However, the absolute amount of these fatty acids stayed the same in the initial and in the control group. Meanwhile, as dietary lipid level increased, the percentages of these fatty acids in body lipids of fish at the end of the trial also increased.

Spawning Behaviors in the Bluehead Chub, Nocomis leptocephalus, River Chub, N. micropogon and Central Stoneroller, Campostoma anomalum

Spawning behaviors were filmed and observed in the nest-building minnows, the bluehead chub, Nocomis leptocephalus, and river chub, N. micropogon. Analysis of videotapes exposed previously unreported behaviors (e.g., female retroflexure) and a precise sequence of male-female interactions that coordinated a successful spawn. Reproductive behaviors were classified into six sequential categories (interim, approach, alignment, run, clasp, dissociation) to facilitate interspecific comparisons. The most conspicuous differences between species involved the intensity of the female's retroflexure and the male's spawning clasp (strong in N. leptocephalus vs. weak in N. micropogon) and reproductive behaviors of subordinate males. In N. leptocephalus, subordinate males spawned concurrently and independently of the resident male over a communal nest, whereas in N. micropogon a subordinate acted like a satellite male and stole spawns from the nest-building male. In addition, heterogeneric spawning clasps involving a male and female N. leptocephalus and a male central stoneroller, Campostoma anomalum, are newly described.

Ceratichthys micropogon Cope, 1865 (currently Nocomis micropogon: Osteichthyes, Cypriniformes): proposed conservation of usage of the specific name by the designation of a neotype

Ceratichthys micropogon Cope, 1865 (currently Nocomis micropogon: Osteichthyes, Cypriniformes): proposed conservation of usage of the specific name by the designation of a neotype

Reproductive Behavior, Captive Breeding, and Restoration Ecology of Endangered Fishes

Species recovery efforts generally focus on in situ actions such as habitat protection. However, captive breeding can also provide critical life history information, as well as helping supplement existing or restoring extirpated populations. We have successfully propagated nine species in captivity, including blackside dace, spotfin chubs, bloodfin darters, and boulder darters. Threatened blackside dace, Phoxinus cumberlandensis, were induced to spawn in laboratory aquaria by exposing them to milt from a reproductively mature male stoneroller, Campostoma anomalum or river chub, Nocomis micropogon. The latter are nest-building minnows, with which Phoxinus may spawn in nature. Eggs are broadcast among gravel and pebbles. Blackside dace individuals reared in captivity were used for translocation. Threatened spotfin chubs, Cyprinella monacha, fractional crevice spawners, deposited eggs in laboratory aquaria in the spaces created between stacks of ceramic tiles. Captively produced spotfin chubs were used as part of a larger stream restoration and fish reintroduction project in the Great Smoky Mountains National Park. The bloodfin darter, Etheostoma sanguifluum, was first used as a surrogate to develop techniques for spawning a closely related species, the endangered boulder darter, E. wapiti. Both darter species mated in a wedge created between two ceramic tiles. Our efforts have had variable but generally high success, with survival rates of 50–90% of eggs deposited. Captive production of nongame fishes can aid recovery of rare species or populations, aid in watershed restoration, and can help to refine water quality standards. In addition, captive breeding allows discovery of important behavioral or life history characteristics that may constrain reproduction of rare species in altered natural habitats.

Lack of Evidence for the Validity of Rhinichthys bowersi (Cyprinidae)

Goldsborough and Clark (1908) described the minnow Rhinichthys bowersi from Dry Fork and Shavers Fork of the Cheat River, West Virginia. Raney (1940a) reidentified the holotype of R bowersi as a hybrid Nocomis micropogon X R cataractae. Stauffer et al. (1979) reexamined morphometric and meristic characters of N. micropogon, R. cataractae, and 42 specimens of the putative hybrid collected from the Monongahela basin. They concluded R. bowersi to be unquestionably of hybrid origin but felt it constituted a morphological species based on its distinct range, consistent characters, and apparent success in nature. Stauffer et al. (1979) refrained from assigning taxonomic status to R bowersi due to insufficient data.

Entrainment by river chub nocomis micropogon and smallmouth bass micropterus dolomieu on cylinders

Sympatric stream-dwelling river chub (Nocomis micropogon) and smallmouth bass (Micropterus dolomieu) were video-taped swimming in the presence of single cylinders spanning a flume. Fish were acclimated and tested at 13, 18 and 23 degreesC swimming in an increasing-velocity test with single vertically or horizontally oriented cylinders 6.4, 13, 19 or 25 mm in diameter. Cylinder orientation had little effect on entrainment. Both species avoided cylinders at low speeds. At intermediate speeds, some fish entrained on the cylinders, but they were displaced at higher speeds. Entrained fish made no regular swimming motions, but the median and paired fins and the body moved continuously and irregularly. The periodicity of body perturbations decreased and the amplitude increased with current speed. These also increased with cylinder diameter, but the variability was high and differences were not significant. Chub entrained in larger numbers and for longer over a wider range of current speeds and temperatures than bass. Entrainment by chub increased with cylinder diameter up to 13-19 mm, but declined for 25 mm cylinders. Bass did not entrain on 6.4 mm and 25 mm cylinders and showed very little entrainment at 13 and 18 degreesC, but entrainment was similar to that of chub at 23 degreesC.