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Batch spawning, the act of spawning more than once within a spawning season, is assessed in six species of minnows (Cyprinidae) from Ontario, Canada. The bimodal frequency distribution of egg size in mature specimens suggests that the following species are batch spawners: Blacknose Dace (Rhinichthys atratulus), Brassy Minnow (Hybognathus hankinsoni), Common Shiner (Luxilus cornutus), Creek Chub (Semotilus atromaculatus), and Hornyhead Chub (Nocomis biguttatus). However, there is no evidence that Northern Pearl Dace (Margariscus nachtriebi) is a batch spawner. Thus, we now have evidence that 11 of 39 cyprinid species in Ontario are batch spawners. Knowledge about the reproductive habits of these species should be integrated into the comprehensive standards for the protection of fish habitat in Ontario to ensure the survival of populations.

Due to widespread stocking, Rainbow Trout (Oncorhynchus mykiss Walbaum) are perhaps the most widely distributed invasive species in the world. Nonetheless, little is known about the effects of stocked Rainbow Trout on native non‐game species. We conducted experiments in an artificial stream to assess the effects of hatchery Rainbow Trout on home range and behaviour of Warpaint Shiners (Luxilus coccogenis Cope), a common minnow frequently found in stocked Southern Appalachian streams. We used the LoCoH algorithm to generate polygons describing the home ranges used by Warpaint Shiners. When a stocked trout was present Warpaint Shiners: (a) increased home range size by 57%, (b) were displaced into higher velocity mesohabitats, and (c) reduced mean overlap between the home ranges of individual warpaint shiners. Rainbow Trout did not significantly affect the edge/area ratio of Warpaint Shiner home ranges. Warpaint Shiner density (two and five fish treatments) did not significantly affect any response variable. Displacement from preferred microhabitats and increases in home range size likely result in increased energy expenditure and exposure to potential predators (i.e., decreased individual fitness) of Warpaint Shiners when stocked trout are present.

Histologic studies of fish from Douglas Lake, Cheboygan County, Michigan, USA show that Diplostomum spp. infect the lens of spottail shiners (Notropis hudsonius) and common shiners (Luxilus cornutus). In contrast, infection was confined to the choroidal vasculature of yellow perch (Perca flavescens), and the morphology of the pigment epithelium and retina in regions adjacent to the metacercariae was abnormal. The difference in location of metacercariae within the host suggested that different Diplostomum species may infect shiners and perch in Douglas Lake. Species diversity was investigated by sequencing the barcode region of the cytochrome oxidase I gene of metacercariae. Four species of Diplostomum were identified, all four of which were present in shiner lenses; however, only Diplostomum baeri was present in the perch choroid. To determine whether infection of perch eyes affects the response of the retina to a light stimulus, electroretinograms (ERG) were recorded. The amplitude of the b-wave of the ERG was reduced and the b-wave latency was increased in infected perch, as compared to uninfected eyes, and the flicker-fusion frequency was also reduced. Infection of the yellow perch choroid by Diplostomum baeri, which shows strong host and tissue specificity, has an adverse effect on retinal function, lending support to the hypothesis that parasite-induced impairment of host vision may afford Diplostomum baeri the evolutionary benefit of increasing the likelihood of transmission, via host fish predation, to its definitive avian host. Keywords: Diplostomum, Electroretinogram, Lens, Retina, Common shiner (Luxilus cornutus), Spottail shiner (Notropis hudsonius), Yellow perch (Perca flavescens)

Standard metabolic rates (SMR) were measured empirically for carmine shiner Notropis percobromus and common shiner Luxilus cornutus to develop SMR models that predict metabolic responses of each species under thermal conditions observed in the wild. SMR increased significantly with body mass and rising water temperature, ranging from 0.05 mg O2 h-1 at 10°C to 0.89 mg O2 h-1 at 20°C for N. percobromus weighing 0.6-2.5 g and from 0.11 mg O2 h-1 at 10°C to 0.98 mg O2 h-1 at 20°C for L. cornutus weighing 0.8-6.6 g. SMR models significantly differed between sympatric species on account of differences in model intercepts (RA) and temperature coefficients (RQ), however, the allometric relationships between mass and SMR did not significantly differ between species. Known distribution of N. percobromus and L. cornutus includes the Birch River located in Manitoba, Canada, where N. percobromus is listed as Endangered. Little is known about the physiology of N. percobromus or the species' ability to acclimate or adapt to different environmental conditions. While size differences between species contributed, in part, to differences in SMR predictions for Birch River populations, SMR trends (< 2 mg O2 h-1 ) for individuals weighing 1 g were similar for both species across daily temperatures. Respirometry experiments contributed to developing species-specific SMR models and inform on the effect of natural and anthropogenic stressors, namely water temperature, on the conservation of N. percobromus in this ecosystem.

The diel diet composition and feeding periodicity of Luxilus cornutus (common shiner), Exoglossum maxillingua (cutlip minnow), Semotilus corporalis (fallfish), and Notropis hudsonius (spottail shiner) were examined in the Salmon River, New York over a 24 h period during the summer. Chironomids were the major prey of common shiner (60.6%) and cutlip minnow (54.7%), whereas terrestrial invertebrates (30.0%) and amphipods (38.4%) were the primary food of fallfish and spottail shiner, respectively. Diet overlap was high between common shiner and cutlip minnow (Morisita's index = 0.88) and moderate between fallfish and common shiner (0.54) and fallfish and cutlip minnow (0.50). Diel temperal variation in diet composition was greatest (0.64) for spottail shiner. Three species exhibited diel variation in food consumption. Fallfish had a distinct feeding peak, whereas peak food consumption of common shiner and cutlip minnow occurred over a more extended period. Spottail shiner did not have a distinct f...

Two separate field experiments were conducted in a series of small boreal lakes to test for the attraction of egg predators to lake trout Salvelinus namaycush spawning shoals and subsequently to determine whether chemosensory cues attract egg predators to these sites. In the first experiment, minnow traps set on spawning sites captured significantly more egg predators than those set on structurally similar non-spawning sites. Captures of slimy sculpin Cottus cognatus, common shiner Luxilus cornutus, blacknose shiner Notropis heterolepis and virile crayfish Orconectes virilis were more than double on spawning sites relative to non-spawning sites for the two study lakes. To test whether chemosensory cues could attract egg predators to S. namaycush spawning sites, paired minnow traps were placed on eight to 10 sites in each of the three study lakes; one trap contained visually concealed S. namaycush spawning substratum and the other with visually concealed non-spawning substratum. Traps containing spawning substratum consistently captured more fish and had higher mean daily catches than those that contained non-spawning substratum. The combined results demonstrate a greater prevalence of egg predators onS. namaycush spawning shoals that appears to be the result of chemosensory attraction to spawning substratum.

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.

Few studies have been conducted to evaluate the effectiveness of nature-like fishways, particularly in low gradient warmwater streams with diverse fish communities. We evaluated a nature-like fishway that was installed to facilitate upstream passage at a low head dam on Indian Creek near Spencerville, Ontario, Canada. A passive integrated transponder (PIT) array was used to quantify attraction and passage efficiency for 391 PIT tagged warmwater fish, represented by seven species. Attraction efficiency for the three most common species, common shiner (Luxilus cornutus), creek chub (Semotilus atromaculatus) and white sucker (Catostomus commersonii), was 63.3%, 83.7% and 65.6%, respectively, and passage efficiencies were 5.1%, 38.4% and 25%, respectively. Creek chub were able to locate the fishway in less time than white sucker and common shiner; however, took longer to successfully pass. Manipulation of creek chub release locations was used to separate issues of attraction and passage and revealed that passage efficiency was highest (76.2%) for those released within the fishway and intermediate for those released at the entrance (42.1%). This multispecies fishway improved stream connectivity, but additional work is needed to fine tune its configuration. Similar projects that engage stakeholders in nature-like fishway construction are a promising approach for the thousands of small dams that occur on low gradient streams around the globe, but those studies should incorporate a biological evaluation to ensure that attraction and passage efficiency are optimised.

The purpose of this study was to assess the validity of age estimates for the striped shiner Luxilus chrysocephalus and the duskystripe shiner Luxilus pilsbryi using asterisci otoliths, scales, and length data. Both species were sampled monthly from the headwater reaches of the James River in southwestern Missouri from February 1998 to January 1999. The formation of an annual opaque region was validated using edge analysis, whereby the progression of annulus formation is followed throughout the year. A single opaque region was formed in otoliths, primarily during May in striped shiners and June and July in duskystripe shiners. Agreement between otolith and scale ages was over 95% for fish 0–3 years old. However, scales commonly underestimated age for fish of ages greater than 3. For both species, the ages of individuals based on otoliths ranged from 0 to 6 years. Population age structure indicated higher rates of survival and longevity for females and faster growth rates for males of both species...

There is a distinct need for fishway designs that are passable by small-bodied fishes. Like many lotic systems worldwide, the streams of the North American Great Plains are frequently fragmented by instream structures and other potential migration barriers. This makes small-bodied fishes of the North American Great Plains appropriate species to use for fishway development. The swimming and jumping abilities of brassy minnow Hybognathus hankinsoni, Arkansas darters Etheostoma cragini, and common shiners Luxilus cornutus, acclimated to water temperatures of 10, 17.5, and 25°C, were quantified in the laboratory. Endurance increased with temperature for brassy minnow but not for the other two species. Based on swimming trial results, current velocities in fishways should not exceed 64 cm/s for brassy minnow or common shiners and 32 cm/s for Arkansas darters. Jumping experiments showed that the presence of a low vertical barrier (5 cm high) dramatically reduced the probability of upstream movement of ...

In this study, we use restriction fragment length polymorphisms (RFLP) of the mtDNA ND2 gene to identify to species cyprinid eggs collected from a spawning aggregation substrate in the Pascagoula River system. A library was generated with inter- and intra-specific RFLP patterns for nine cyprinids: Notropis baileyi, N. texanus, N. longirostris, N. amplamala, Nocomis leptocephalus, Luxilus chrysocephalus, Lythrurus roseipinnis, and Cyprinella venusta. Eggs of three species were identified from a single nest, while only one species was observed spawning at the site. These results confirm that RFLP is an effective method for identifying unknown eggs of nest associates, and North American cyprinids in general.

Members of the genus Cyprinella are abundant and broadly distributed cyprinids in central and eastern rivers of North America. Currently, 30 species are placed in this genus, including seven species restricted to Mexico and three barbeled species formerly placed in different genera (Hybopsis, Erimonax). Phylogenetic analyses were performed for all recognized species of Cyprinella plus species from 14 related genera using complete nucleotide sequences of one mitochondrial (cytochrome b) and one nuclear (Rag1) gene. Cyprinella revealed high levels of genetic divergence between species in both genes compared with species from other related genera examined. Analyses of mitochondrial sequences from 98 specimens of Cyprinella revealed the gene trees of some species as non-monophyletic (i.e., C. venusta, C. lepida, C. nivea, C. lutrensis, C. whipplei). Mitochondrial analyses recovered nine well-supported species groups within a main clade inclusive of most species of Cyprinella, although resolution regarding the monophyly of the genus or its relationships with other genera was poorly resolved, except for C. callistia and C. monacha, two species that are apparently not part of the genus. Analyses of nuclear gene sequences from selected distinctive mitochondrial clades also recovered these nine clades and resulted in shorter branches but greater resolution at more basal nodes. Nuclear data also rejected the inclusion of C. monacha in Cyprinella and indicated that Cyprinella is not monophyletic if Tampichthys and Codoma are recognized as valid genera. A major Clade A (formed by Cyprinella, Tampichthys, Codoma) is more closely related to Pimephales, Opsopoeodus, Hybognathus and some Notropis than to Luxilus and Lythrurus as previously hypothesized. Although mitochondrial data are highly informative phylogenetically, our research revealed fundamental conflicts among mitochondrial and nuclear data for several species of Cyprinella. Interestingly, nuclear trees recovered some species resolved as polyphyletic with mitochondrial variation as monophyletic. While we remain highly supportive of phylogenetic studies using mitochondrial genes and genomes, this study does highlight the utility of nuclear data by identifying issues of possible hybridization or retained ancestral polymorphisms and lineage sorting that can yield erroneous hypothesis in studies using only mit-DNA analyses, while shedding invaluable light on the phylogeny of this controversial group of shiners.

Freshwater fish assemblages are sensitive to changes in land use, but it is unclear how rapidly assemblages respond to such change or how closely they track physical changes in the stream environment. We monitored fish assemblages at the outflow of three watersheds on the outer coastal plain of Mississippi over a period of 8 y. The watersheds differed in patterns of land use, being predominantly forested, rapidly urbanizing, and long-urbanized, respectively. Watersheds were distinct in fish species composition, differing primarily in abundance of Etheostoma lynceum, E. stigmaeum, Luxilus chrysocephalus and Lythrurus roseipinnis. Species richness was consistently greatest at the predominantly forested site and least at the urbanized site. Fish assemblages were distinguishable in terms of substrate preference, water-speed, silt tolerance, and trophic habit. The stream draining the urbanizing watershed showed an increase in richness of species of high silt tolerance and a decrease in richness of tho...

Local extirpations of the federally endangered Topeka Shiner (Notropis topeka) have been linked to the introduction of Largemouth Bass (Micropterus salmoides). However, because other native minnow species have persisted at these locations, our objective was to test whether Topeka Shiners were more susceptible to predation by Largemouth Bass than other native minnows. We conducted behavioral observations of Topeka Shiners, Red Shiners (Cyprinella lutrensis), Bluntnose Minnows (Pimephales notatus), and Common Shiners (Luxilus cornutus) in an indoor experimental stream, in which we examined the interactive effects of cover and the presence of a predator on longitudinal and lateral position, height in water column, cover use, and activity of these minnows. Significant differences in habitat use and response to bass were observed among species, but there was no evidence to suggest that Topeka Shiners would be more susceptible to predation than other native species. Subsequent experiments in outdoor ex...

A review of specimens previously reported as Dactylogyrus banghami from cyprinid fishes in North American Gulf of Mexico Coastal drainages revealed 6 different species: Dactylogyrus beckeri from Cyprinella venusta; Dactylogyrus perlus from Luxilus chrysocephalus isolepis; Dactylogyrus sp. cf. beckeri from Lythrurus atrapiculus and Lythrurus bellus; Dactylogyrus hydrophloxi n. sp. from Notropis baileyi; Dactylogyrus magnibulbus n. sp. from Notropis longirostris and Notropis ammophilus; and Dactylogyrus parvibulbus n. sp. from Notropis texanus and Notropis hypsilepis.

Most freshwater food web models assume that fish occupy the top trophic level. Yet many diet studies and a few caging and artificial stream experiments suggest that birds may be top predators in many freshwater systems. We conducted a large-scale field experiment to test whether avian predators affect the size distribution and abundance of fish in two midwestern streams. We used a combination of netting and perches to manipulate predation by Great Blue Herons (Ardea herodias) and Belted Kingfishers (Ceryle alcyon), and measured the response in the fish assemblage. Bird exclusions caused significant increases in medium size classes of two common prey, striped shiners (Luxilus chrysocephalus) and central stonerollers (Campostoma anomalum). We show that these species of piscivorous birds can alter the abundance of common prey and thus need to be considered more fully when attempting to explain the structure of aquatic food webs. Corresponding Editor: O. J. Schmitz.

Cyprinids in small streams tend to segregate spatially to reduce competitive interaction and avoid predation. Understanding environmental parameters by which these fishes segregate provides valuable information on structure of fish guilds. Previous multivariate analyses of field data suggest spatial segregation occurs vertically within the water column and in relation to aquatic plants. In an experimental flume we controlled water flow and these two parameters to further investigate microhabitat partitioning of three cyprinid species: blacktail (Cyprinella venusta), bluntface (C. camura), and striped shiners (Luxilus chrysocephalus). Fish distribution relative to the environmental parameters was quantified with videography and expressed as percent occurrence. We observed significant differences across fish treatments in microhabitat selection relative to water flow and water column, and differences in species overlaps. These data support the idea that vertical position in water column is a major ...

Recent theoretical work suggests that predator impact on local prey density will be the result of interactions between prey emigration responses to predators and predator consumption of prey. Whether prey increase or decrease their movement rates in response to predators will greatly influence the impact that predators have on prey density. In stream systems the type of predator, benthic versus water-column, is expected to influence whether prey increase or decrease their movement rates. Experiments were conducted to examine the response of amphipods (Gammarus minus) to benthic and water-column predators and to examine the interplay between amphipod response to predators and predator consumption of prey in determining prey density. Amphipods did not respond to nor were they consumed by the benthic predator. Thus, this predator had no impact on amphipod density. In contrast, amphipods did respond to two species of water-column predators (the predatory fish bluegills, Lepomis macrochirus, and striped shiners, Luxilus chrysocephalus) by decreasing their activity rates. This response led to similar positive effects on amphipod density at night by both species of predatory fish. However, striped shiners did not consume many amphipods, suggesting their impact on the whole amphipod "population" was zero. In contrast, bluegills consumed a significant number of amphipods, and thus had a negative impact on the amphipod "population". These results lend support to theoretical work which suggests that prey behavioral responses to predators can mask the true impact that predators have on prey populations when experiments are conducted at small scales.

Samples of Luxilus cornutus, Luxilus chrysocephalus, and their hybrids were collected along hypothesized routes of dispersal from Pleistocene refugia to examine the significance of geographic variation in patterns of intro- gression between these species. Patterns of allozyme and mitochondrial DNA (mtDNA) variation were generally consistent with those from previous studies. Tests of Hardy-Weinberg equilibrium revealed significant deficiencies of heterozygotes in all samples, indicating some form of reproductive isolation. Mitochondrial DNAs of each species were not equally represented in F1 hybrids; however, this bias was eliminated when the two largest samples were excluded from the analysis. Backcross hybrids exhibited biased mtDNA introgression, as samples from Lake Erie (eastern) and Lake Michigan (western) drainages showed significant excesses of mtDNAs from L. chrysocephalus and L. cornutus, respectively, relative to frequencies of diagnostic allozyme markers. The extent and direction of allozyme and mtDNA introgression was quantified by calculating isolation index values from morphologically "pure" individuals of each species from each locality. Analysis of variance of these measures identified limited introgression of allozyme variants with no geographic pattern, but significant differences in direction of mtDNA introgression between drainages (i.e., postglacial dispersal route). Association between patterns of mtDNA introgression and dispersal route across the latitudinal width of the contact zone is best explained by genetic divergence during past isolation of ancestral pop- ulations from these drainages. These results identify a significant role for historical effects in the evolution of repro- ductive isolation and the process of speciation.

The cyprinid fishes Luxilus cornutus and Luxilus chrysocephalus hybridize extensively in a zone extending through the Great Lakes region with extensive introgression of L. cornutus mtDNA occurring in populations of L. chrysocephalus south of the present hybrid zone in Ohio. Western populations of these two species occur adjacent to one another in Missouri but hybridization has never been observed. In order to determine if hybridization has occurred historically in Missouri, allopatric populations of L. chrysocephalus were analysed for mtDNA introgression. Extensive introgression of L. ***cornutus mtDNA was observed in most populations of L. chrysocephalus in Missouri resulting in the elimination of L. chrysocephalus mtDNA in many populations. Luxilus cornutus mtDNA in L. chrysocephalus is found approximately 300 km south of extant L. cornutus populations in Missouri. Luxilus chrysocephalus mtDNA was replaced by four unique L. cornutus mtDNA haplotypes, with one particular haplotype becoming fixed in several L. chrysocephalus populations. The pattern of introgression suggests that historically L. cornutus occupied a more southern distribution in Missouri bringing it into contact with western populations of L. chrysocephalus and resulting in a hybrid zone.

The longevity of 7 forms of actinosporean spores and the reaction of 6 forms of actinosporeans to fish mucus were investigated. The maximum longevity of actinosporean spores kept at ambient laboratory temperatures was 14 days. Spore longevity ranged from 11 to 14 days among actinosporeans. The reaction of spores to fish mucus varied among the actinosporeans. Triactinomyxon F of Xiao and Desser, 1998 reacted only to the mucus of the common shiner Luxilus cornutus, and golden shiner Notemigonus crysoleucas, whereas the aurantiactinomyxon form of Xiao and Desser, 1998, and raabeia B of Xiao and Desser, 1998 reacted readily to mucus of all fish species tested. The differences in reaction to fish mucus among actinosporeans may indicate their different host range. These results indicate that actinosporean spores are short-lived and that actinosporeans respond to their hosts by chemodetection.

The nematode Rhabdochona cotti Gustafson, 1949 is redescribed from specimens collected from the intestine of the blue ridge sculpin Cottus caeruleomentum (a new host record), a recently described fish species, from Little Fishing Creek in Maryland, USA. The measurements of these specimens, collected in November 2005, are generally smaller than those reported in the original description of R. cotti, this being probably associated with the nematode’s seasonal maturation cycle or the different host species. As revealed by SEM, the deirids of R. cotti are simple (not bifurcate), in which this species differs from almost all North American congeners. Of these, simple deirids, filamented eggs and a rounded tail tip in females occur only in Rhabdochona longleyi, but it distinctly differs from R. cotti in the smaller number of anterior prostomal teeth (6 vs. 14). Rhabdochona rotundicaudatum is considered a junior synonym of Rhabdochona cascadilla; numerous specimens of the latter were collected from Semotilus atromaculatus, Luxilus cornutus and Notropis rubellus from the type locality (Eramosa River, Ontario, Canada) (unpublished). Rhabdochona paxmani and Rhabdochona salmonis are synonymized with Rhabdochona kisutchi, whereas Rhabdochona californiensis is considered a junior synonym of R. cascadilla. The need of a taxonomic revision of North American species of Rhabdochona is stressed.

The concentrations of 20 polychlorinated biphenyl (PCB) congeners were measured in periphyton, herbivorous fish (stoneroller minnows, Campostoma anomalum), and omnivorous fish (striped shiners, Luxilus chrysocephalus) in an industrially contaminated stream and a reference stream in eastern Tennessee. The sum of the concentrations of the 20 congeners, normalized by dry mass, was one to two orders of magnitude higher in stonerollers and shiners than in periphyton. Normalizing PCB concentrations by lipid mass reduced concentration differences between periphyton and stonerollers, but PCBs per unit lipid in stonerollers were still 50-350% higher than those in periphyton. Shiners had significantly higher lipid-specific PCB concentrations than did stonerollers, so a trophic hierarchy of primary producerherbivoreomnivore was evident in lipid-specific PCB concentrations. Differences in lipid type, exposure duration, and exposure sources may account for the trophic-level differences in total PCBs. Congener profiles were roughly similar in periphyton, stonerollers, and shiners: five congeners (IUPAC numbers 101, 110, 138, 153, and 180) constituted60% of the total mass of PCBs analyzed in all three trophic levels. However, stoneroller and shiner tissue was enriched in congeners 153, 118, and 187 relative to periphyton; congeners 153 and 187 are resistant to metabolic breakdown by monooxygenases found in fish liver. Principal component analysis of congener percentages separated periphyton from fish and distinguished between sampling locations.

Host fishes, fecundity estimates, and gravid periods were identified for four species of freshwater mussels from the Lake Pontchartrain basin, Louisiana. Two of the mussel species have broad distributions both in the Mississippi River and elsewhere in Louisiana: Villosa lienosa (Conrad, 1834) and Lampsilis teres (Rafinesque, 1820). The other two species have more restricted distributions: Quadrula refulgens (Lea, 1868) and Lampsilis ornata (Conrad, 1835). Lampsilis ornata is listed as a species of concern in Louisiana. Of the 23 species of fishes tested as potential hosts, we found 4 previously unknown hosts for Villosa lienosa: Lepomis megalotis, Lepomis humilis, Lepomis microlophus and Lepomis cyanellus, and confirmed 2 previously documented: Lepomis macrochirus and Micropterus salmoides. Villosa lienosa was gravid from April until June and had an estimated fecundity of 38,562 + 3,073 glochidia/female. For Lampsilis ornata we established a host relationship with Luxilus chrysocephalus, and confirmed Micropterus salmoides as a host. Lampsilis ornata was gravid from February until April and had a fecundity estimate of 451,214 + 27,239 glochidia/female. Lampsilis teres was gravid from April until September and had a fecundity estimate of 407,333 + 24,727 glochidia/female. We confirmed three hosts for L. teres: Micropterus salmoides, Pomoxis annularis, and Lepomis humilis, and identified two new hosts: Lepomis microlophus and Notropis venustus. Only a single Quadrula refulgens was found gravid in late June and its fecundity was estimated at 32,450 glochidia and a host was identified as Pylodictis olivaris.

This report summarizes the monitoring of fish kills in upper East Fork Poplar Creek (EFPC) from July 1990 to June 1993. Since the opening of Lake Reality (LR) in 1988, total numbers of fish inhabiting upper EFPC have increased. However, species diversity has remained poor. Water quality data have been collected in upper EFPC during the time period covered in this report. Total residual chlorine (TRC) levels have exceeded federal and state water quality criteria over the years. However, with the installation of two dechlorination systems in late 1992, TRC levels have been substantially lowered in most portions of upper EFPC. By June 1993, concentrations of TRC were 0.04 to 0.06 mg/L at the north-south pipes (NSP) and below detection limits at sampling station AS-8 and were 0 to 0.01 mg/L at the inlet and outlet of LR. The daily chronic fish mortality in upper EFPC has been attributed to background stress resulting from the continuous discharge of chlorine into upper EFPC. Mean daily mortality rates for 22 acute fish kills were three fold or more above background and usually exceeded ten fish per day. Total number of dead fish collected per acute kill event ranged from 30 to over 1,000 fish; predominant species killed were central stonerollers (Campostoma anomalum) and striped shiners (Luxilus chrysocephalus). Spills or elevated releases of toxic chemicals, such as acids, organophosphates, aluminum nitrate, ammonia, or chlorine, were identified as possible causative agents; however, a definitive cause-effect relationship was rarely established for any acute kills. Ambient toxicity testing, in situ chemical monitoring, and streamside experiments were used to examine TRC dynamics and ambient toxicity in EFPC.

The size of seven neural structures was compared in 51 species of Notropis, Pteronotropis, Cyprinella, Luxilus, Lythrurus, and Hybopsis, and related to the turbidity of the species’ habitat. This last parameter was assessed for each species by personal communication with 42 ichthyologists. To control for size differences among species, all analyses were performed on the residuals from a regression of each character on standard length. Principal components analysis (PCA) of the residuals produced four significant PC-axes that together explained 65% of the total variation represented in the original variables. The size of brain structures concerned with vision, olfaction, and gustation was correlated with habitat turbidity. Two-way Analyses of Covariance (ANCOVAs) revealed significant differences between species in the size of all structures. Sexual dimorphism was found in the size of the olfactory bulb and the cerebellum, and significant two-way interactions (species vs. sex) were detected for the telencephalo, optic lobes, cerebellum, vagal lobe, and the eye. Cluster analysis indicated that neither similar turbidity preference nor shared phylogeny is alone sufficient to explain the observed differences in brain morphology.

Despite use of several character sets, phylogenetic relationships among species groups of the cyprinid genus Luxilus remain unresolved. To address this problem, cytochrome b was sequenced from representatives of each taxonomic unit within the genus and from several outgroups. When all outgroups were included, distance and parsimony analyses identified a single topology: (((L. cerasinus, L. zonatus group) L. cornutus group) L. coccogenis group). However, this topology was not appreciably better than alternative hypotheses from different character sets, and monophyly of the genus was not well supported. Saturation effects associated with contrasts involving the outgroup Cyprinella may have impacted resolution. When only Lythrurus was used as the outgroup, the same topology was recovered, and, except for the placement of L. cerasinus, relationships were well supported. General concordance of these results with those based on morphological characters provides support for a close relationship of the cornutus and zonatus groups and for basal position of the coccogenis group.

bers of the family Cyprinidae remain unresolved, and the genus Luxilus remains one of its most controversial groups. In this study, restriction endonuclease analysis of mitochondrial DNA (mtDNA) was used to infer relationships among species of Luxilus, providing an additional character set for evaluating relationships within the genus. Phylogenetic analysis of these data resolved the major groups previously described from morphology and allozymes (the L. coccogenis species group containing L. coccogenis and L. zonistius; the L. cornutus species group consisting of L. albeolus, L. cornutus, L. chrysocephalus chrysocephalus, and L. c. isolepis; the L. zonatus species group containing L. cardinalis, L. pilsbryi, and L. zonatus; and the L. cerasinus species group containing L. cerasinus). Branching order within these groups were well resolved and consistent with previous hypotheses of relationship, with some minor exceptions. The relationships among the species groups (including L. cerasinus) were uncertain. Evaluation of previously proposed relationships of the subgroups within Luxilus relative to the mtDNA data suggests that several of these hypotheses are equally probable, implying that the present data are incapable of resolving phylogenetic relationships at this level of divergence. Correlation between mtDNA sequence divergences and allozyme distances from this and other studies of cyprinids suggests that cleavage site data from the entire mtDNA molecule will most likely be informative for phylogenetic study of cyprinids when mtDNA divergences and allozyme distances are less than 9.5% and 0.20, respectively.

Chromosomal nucleolus organizer region (NOR) phenotypes are documented for all extant taxa of the North American cyprinid genus Luxilus. All nine species, including two subspecies of L. chrysocephalus (L. c. chrysocephalus and L. c. isolepis), possess 2n = 50 chromosomes. Five species and one population of L. c. isolepis from the Blue River in Oklahoma possess a single pair of NORbearing chromosomes. These included L. cerasinus and L. c. isolepis from Oklahoma (NOR phenotype C), L. zonistius (NOR phenotype D,), and all three species (L. cardinalis, L. pilsbryi, and L. zonatus) of the L. zonatus group (NOR phenotype Dj). Four taxa (L. albeolus, L. coccogenis, L. c. chrysocephalus, and L. cornutus) and populations of L. c. isolepis from Alabama, Mississippi, and Louisiana possess two pairs of NOR-bearing chromosomes (NOR phenotype C, D,). A serial banding procedure (Z-banding) was used to test homology of C, D,, and D, NOR chromosomes. The NOR chromosome data support monophyly of the L. cornutus group (L. albeolus, both subspecies of L. chrysocephalus, and L. cornutus) and L. coccogenis. Assuming the L. coccogenis group (L. coccogenis and L. zonistius) is monophyletic, as suggested by morphological, allozymic, and mtDNA data, the chromosomal data support the hypothesis that the L. coccogenis and L. cornutus groups are sister taxa and that L. cerasinus is sister to the L. coccogenis groupL. cornutus group clade. Because the D, NOR chromosome of all three species of the L. zonatus group does not occur elsewhere in Luxilus, there is no chromosomal evidence for a phyletic relationship between the L. zonatus group and any other species in Luxilus. The hypothesis that the L. coccogenis group is sister to the L. cornutus group suggests that the "missing" species of Luxilus in the Ohio River-northern Atlantic slope drainages may have been a member (or ancestor) of the L. cornutus group.

Allozyme electrophoresis, restriction endonuclease analysis of mitochondrial DNA (mtDNA), and principal component analysis (PCA) of scale counts were used to characterize hybridization between Luxilus cornutus and L. cerasinus at a single locality (Barbour Creek, James River drainage, southwestern Virginia). PCA provided some separation between these species and L. albeolus from allopatric populations; however, overlap among all three species prevented complete discrimination of these forms with morphological characters alone. Application of morphological and genetic characters diagnostic for L. cornutus and L. cerasinus identified many hybrids in Barbour Creek. Most were F,s (as indicated by heterozygous genotypes at all four diagnostic allozyme loci) and exhibited mtDNAs of L. cerasinus. These data were contrasted with other hybridizing species of the genus Luxilus, which showed more extensive introgression. In addition, one individual exhibited morphological and genetic characteristics consistent with its identification as L. albeolus, providing the first report of this species in the James River. These results do not refute or support the hypothesis of hybrid origin for L. albeolus but highlight the difficulty of discriminating among ancestral polymorphism, convergence, and past hybridization.

Comparison of allozymes and restriction endonuclease cleavage maps of mitochon- drial DNA (mtDNA) was used to infer phylogenetic relationships among four species of minnows in the cyprinid genus Notropis. Statistical analysis of the allozyme data supported the monophyly of N. chrysocephalus and N. cornutus (subgenus Luxilus) relative to N. photogenis and N. rubellus (subgenera Notropis and Hydrophlox, respectively). In contrast, statistical analysis of the mtDNA cleavage site data provided no resolution for these relationships. Given the rapid rate of vertebrate mtDNA evolution, mtDNA data were expected to provide greater taxonomic resolution than allozyme data. Four possible reasons for this discrepancy were considered; two of these, rate heterogeneity between genes and lineages and introgressive hybridization, were analyzed in detail. Comparison of sequence divergence estimates among genetically different regions of the same mtDNA and among mtDNAs of different species revealed significant variation in the relative rates of change. This variation can lead to intramolecular and interspecific differences in levels of convergence, and, thus, to a loss of phylogenetic resolution. Because of the propensity for these species to hybridize and the possibility of mtDNA introgression, the potential impact of hybridization and introgression was also considered. Given the internal factors affecting the evolution of mtDNA and the population genetic processes affecting its transmission, assumptions of rate homogeneity and of strict vertical inheritance should be closely scrutinized when con- structing phylogenies with mtDNA data. (Mitochondrial DNA; Notropis; evolutionary rates; hybridization; convergence.)

Electrophoretic analyses were performed on blood proteins of the five members of the Notropiscornutus species group. The protein systems included two plasma esterases, transferrin, a pre-albumin and hemoglobin. Plasma protein polymorphism within and between taxa was common. Hemoglobin appeared to be a more consistent and conservative character for assessing phylogenetic relationships. As deduced by both biochemical and morphological evidence, N. cerasinus is the most primitive member of the species group. Uniqueness for several biochemical characters suggests that the striped shiner should be afforded full species recognition as N. isolepis but additional study is needed concerning its relationship with N. cornutus chrysocephalus . The closest biochemical similarity was between the forms interpreted here as subspecies N. cornutus cornutus and N. c. chrysocephalus. N. albeolus clearly evolved from N. c. cornutus but early hybridization with N. cerasinus resulted in limited introgression from that species.

Population samples for all taxa in the subgenus Luxilus of Notropis were genetically analysed by vertical starch gel electrophoresis to detect protein variability. A total of 38 alleles were resolved at 17 presumptive loci. Protein systems examined included adenylate kinase, aspartate aminotransferase, creatine kinase, calcium-binding proteins, general protein, glucosephosphate isomerase, glycerol-3-phosphate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, phosphoglucomutase, and superoxide dismutase. A phylogenetic analysis of the molecular data allows the recognition of four species-groups: (a) the cornutus group including Notropis albeolus, N. chrysocephalus chrysocephalus, N. c. isolepis , and N. cornutus : (b) the zonatus group including N. pilsbryi and N. zonatus ; (c) the coccogenis group including N. coccogenis and N. zonistius ; and (d) the cerasinus group comprised of N. cerasinus alone. Notropis cerasinus exhibits little genetic affinity for the cornutus species-group and is most closely related to the coccogenis species-group. Both phenetic and phylogenetic analyses deny specific status to the isolepis form. A further analysis of isozyme variability at the Pgm-A and Gpi-A loci may clarify the relationship between N. cornutus and N. chrysocephalus .

1. 1. Eight species of the subgenus Luxilus of Notropis (Cyprinidae) were compared with respect to their lactate dehydrogenase and malate dehydrogenase isozyme patterns. 2. 2. This isozymic analysis permitted the resolution of the three distinct phyletic groups within the subgenus. 3. 3. Extensive polymorphism was observed at the lactate dehydrogenase C locus, the function of which is restricted primarily to the liver.

Two forms of the Notropis cornutus (Luxilus) complex occur syntopically in the Grand River system. These have been interpreted by some authors as separate species and by others as subspecies. The forms can be distinguished morphologically by the number of predorsal scales and by pigmentation pattern. It has also been suggested that the upper lethal temperatures of the two differ.This is the first report of a study of these features in syntopic populations. The results indicate that neither physiological nor morphological characters can establish the taxonomic status of these forms and that what is needed is a detailed study of the breeding behaviour of these forms in areas of syntopy.

Foods, feeding periodicity and microhabitat use are reported for coexisting Notropis albeolus, N. ardens and N. cerasinus in the upper Roanoke River drainage, Virginia. All three species primarily occupied pool habitats, ate aquatic insect larvae or terrestrial adult insects, and were diurnal feeders. Notropis ardens (subgenus Lythrurus) was ecologically segregated from N. albeolus and N. cerasinus (both subgenus Luxilus) in vertical spacing in the water column and in taxa of foods used. The two Luxilus species were ecologically more similar, segregated only by vertical differences in microhabitat. Overlaps in resource use among the three species pairs suggested congruence of phylogenetic and ecological similarities. INTRODUCTION The phenomenon of resource partitioning is well-documented in reptile, bird and mammal communities (cf., Pianka, 1973; Schoener, 1974), and in numerous freshwater fish communities closely related, coexisting species differ ecologically, e.g., in microhabitat, food or feeding chronology (Hartley, 1948; Keast, 1965, 1966, 1978; Zaret and Rand, 1971; Werner and Hall, 1976, 1979; Werner et al., 1977). It has often been assumed that some segregation in resource use is a requisite for coexistence of species, and that observed ecological differences among coexisting taxa result from past or present competitive interactions. However, uncritical acceptance of a competition model to account for ecological differences among coexisting fish species may be unwarranted (Sale, 1979), and the plausibility of alternative hypotheses should be considered. Mendelson (1975), for example, suggested that coexisting minnows used resources in patterns set by morphological preadaptation. In eastern North America, minnows of the genus Notropis (Cyprinidae) often occur in multispecies aggregations, using habitats and foods that superficially appear similar. However, Starrett (1950), Whitaker (1977), Gillen and Hart (1980) and Hoover (1981) showed trophic segregation among coexisting Notropis species, and Moyle (1973) and Baker and Ross (1981) demonstrated that coexisting Notropis species segregated vertically into different microhabits. Mendelson (1975) showed that four coexisting Notropis were ecologically segregated more by use of space than by diet. While these studies suggest the importance of dietary and microhabitat segregation among coexisting Notropis, there has been too little comparative research within this diverse genus (at least 119 species) to permit generalization about mechanisms that facilitate species coexistence. In this study we evaluate ecological segregation among three syntopic Notropis species, with emphasis on microhabitat, food and feeding chronology in a complex upland stream system. We also provide information on cold vs. warm weather ecology of the species. Our study focuses on Notropis albeolus (white shiner, subgenus Luxilus), N. ardens (rosefin shiner, subgenus Lythrurus) and N. cerasinus (crescent shiner, subgenus Luxilus), which are the three most common Notropis in the upper Roanoke River drainage above Salem, Virginia (Jordan, 1889; Cairns et al. 1971; Jenkins, 1979). All three coexist in the river mainstream and in larger tributaries, but N. cerasinus occurs somewhat further 'Address reprint requests to Matthews.

The cardinal shiner, Notropis cardinalis, is described as a new member of the subgenus Luxilus in the zonatus species group. It is restricted to the Arkansas and Red river drainages in the Interior Highlands of North America. The new species differs from its close relatives N. pilsbryi and N. zonatus primarily in breeding color patterns, but it is also distinguished by meristic and morphometric features. Distributions of morphological characters of members of the zonatus group are congruent with previously described patterns of genic variation and support the recognition of three species in the Interior Highlands. Phylogenetic analysis of morphological and allozyme characters suggest that N. cardinalis and N. pilsbryi are sister species, and both are in turn sister to N. zonatus. THE cyprinid subgenus Luxilus of Notropis has received considerable taxonomic and systematic attention, probably more than any other species group within the genus. Most of these research efforts have focused on the zonatus species group of the highland streams west of the Mississippi River and east of the Great Plains, most commonly referred to as the Interior Highlands. Since the descriptions of Notropis zonatus and N. pilsbryi, researchers have disagreed as to the number of species involved. Hubbs and Ortenburger (1929) and Hubbs and Brown (1929) placed the two species in synon

(1931). Observations on the Spawning Temperature of Luxilus Cornutis. Transactions of the American Fisheries Society: Vol. 61, No. 1, pp. 215-215.

Nests and/or nest-related behaviors are described for Micropterus dolomieui, Semotilus atromaculatus, Nocomis biguttatus, and Campostoma anomalum in a stream in eastern Oklahoma. Behavior of Notropis pilsbryi over a Semotilus atromaculatus nest is described, and commnents on reproductive behaviors in this and other species of the subgenus Luxilus (genus Notropis) are given. Until recently, information on the breeding habits of North American minnows has been provided primarily by the studies of a limited number of ichthyologists such as Hankinson, Reighard, Forbes and Richardson, Trautman, Hubbs, and Raney (see Miller, 1961, 1964 for citations). Most other contributors to this field have worked primarily with one or two species, and data from this group of authors is often secondary to other life history data and consequently less detailed, though there are numerous exceptions to this general statement, such as the studies of Marshall (1946), Pfeiffer (1955), Van Duzer (1939), Reed (1957), Outten (1957) and others. The majority of these studies, and particularly the most complete and detailed descriptions, have dealt with northern species primarily in New York, Michigan, Ohio, Illinois, and Pennsylvania. The breeding activities of minnows in other regions, the southwest and great plains in particular, are relatively poorly known. Although many streams in this region are too turbid to permit direct observation of behavior in nature, many streams along the western edge of the Ozarks in eastern Oklahoma are clear and include the western-most representatives of our Great Lakes trans-Mississippi fish fauna. Some observations on the behavior of various fish species have been made in some of these streams and clear lakes of eastern and southern Oklahoma by George A. Moore, Carl D. Riggs, and their students. The sparse nature of our knowledge of the breeding activities of cyprinid fishes in this area has prompted preparation of this paper, partly to encourage others to carry out investigations on these interesting fishes and partly to provide some data useful in comparing the behavior of local forms with their eastern cognates.