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The St. Clair River, which flows from Lake Huron to Lake St Clair, receives discharges and emissions from numerous petroleum refineries, petrochemical facilities, and other sources. We used a multi-factor ANOVA to test for spatial and temporal changes in concentrations of trace metals/metalloids in homogenates of fish from Lake Huron (reference site) and two river sites - an industrialized region (Stag Island) and downstream Walpole Island/Chenal Ecarte. In 2002/2003 and in 2014, we sampled 20 adult fish of each sex of the following species: shorthead redhorse (Moxostoma macrolepidotum), yellow perch (Perca flavescens); we added emerald shiner (Notropis atherinoides; unsexed) in 2014. There was a temporal decline of most metals/metalloids in shorthead redhorse at the river sites. Linear Discriminant Analysis separated the 2014 shorthead redhorse by site. Emerald shiners had higher concentrations of metals/metalloids, apart from mercury, than the other species; those concentrations were highest at Chenal Ecarte, which warrants further research. Tissue concentrations of mercury, which declined temporally at Stag Island and Walpole Island, were above the protective guidance for wildlife consumers at all sites, but were lower than predicted to affect fish health. Apart from increased liver size (ANCOVA) in shorthead redhorse at Walpole Island (2014), the health variables in the riverine fish were stable or differed slightly from reference, which indicated good health and reproductive potential. In shorthead redhorse, tissue metals correlated inconsistently with health indices. Further research could ascertain if temporal declines in metals/metalloids in riverine SHRH are benefits of remediation actions or fluctuations with other causes.

This study examines the temporal and spatial variability of the floodplain trophic contribution to the fish community of Lake Saint-Pierre, a large (≈ 300 km2), shallow (≈ 3 m) widening of the St. Lawrence River (Quebec, Canada). We hypothesized that floodplain contribution to fish diet would be maximal during the early growing period following the seasonal flood and at sites located closest to the floodplain. Carbon stable isotope ratios (δ13C) of invertebrates and 35 fish species were analyzed at the beginning and at the end of two growing seasons, at increasing distances from the floodplain. Floodplain contribution, in the form of exported aquatic invertebrates, was estimated at the fish community (littoral versus main river), species and individual fish level, using a stable isotopic mixing model and a linear mixed model selection. As hypothesized, fish captured in the early part of the growing season near the floodplain benefitted from the largest floodplain contribution, which decreased during the late growing season. In addition, floodplain contribution differed among fish species, being higher in small or immature littoral species (northern pike, yellow perch, blackchin and golden shiners) than for larger taxa inhabiting the main river channel (shorthead redhorse, white sucker and channel catfish). Our study revealed that floodplain production during the early growing season represents a key food resource to a large portion of the riverine food web, thus highlighting the essential role of the floodplain in human-altered temperate rivers.

In July 2016, a Husky Energy pipeline spilled 225,000 L of diluted heavy crude oil, with a portion of the oil entering the North Saskatchewan River near Maidstone, SK, Canada. This event provided a unique opportunity to assess potential effects of a crude oil constituent (namely polycyclic aromatic hydrocarbons, PAHs) on a possible sensitive indicator of freshwater ecosystem health, the gut microbiota of native fishes. In summer 2017, goldeye (Hiodon alosoides), walleye (Sander vitreus), northern pike (Esox lucius), and shorthead redhorse (Moxostoma macrolepidotum) were collected at six locations upstream and downstream of the spill. Muscle and bile were collected from individual fish for quantification of PAHs and intestinal contents were collected for characterization of the microbial community of the gut. Results suggested that host species is a significant determinant of gut microbiota, with significant differences among the species across sites. Concentrations of PAHs in dorsal muscle were significantly correlated with gut community compositions of walleye, but not of the other fishes. Concentrations of PAHs in muscle were also correlated with abundances of several families of bacteria among fishes. This study represents one of the first to investigate the response of the gut microbiome of wild fishes to chemical stressors.

Large-bodied fish assemblages were assessed in large rivers across Ontario. The objectives of this study were to (i) determine if there were relationships in large-bodied fish species within rivers; (ii) determine what factors explain the variability in the abundance of large-bodied fish within rivers across Ontario; and (iii) assessed variation in large-bodied fish biodiversity among these river. Standardized index netting was conducted at 22 sites across 12 major rivers and sampled 3889 fish representing 26 species. Species associations were evident based on correspondence analysis. Walleye, Common White Sucker, Northern Pike and Lake Whitefish formed one group; Silver Redhorse, Shorthead Redhorse and Lake Sturgeon (adult and juvenile) formed another; Burbot, Longnose Sucker and Sauger were closely associated; and Lake Cisco, Yellow Perch, Rock Bass, Smallmouth Bass and Brown Bullhead grouped. Canonical correspondence analysis was conducted to link species abundance patterns to environmental conditions. Walleye, Common White Sucker, Lake Whitefish and Smallmouth Bass were ubiquitous. Northern Pike abundance was negatively correlated with river discharge and longitude. Burbot, Sauger and Longnose Sucker abundance were positively correlated with deep rivers and discharge. Whereas Lake Cisco, Yellow Perch and Rock Bass abundance were greater in wider rivers with lower discharge. Lake Sturgeon (adult and juvenile), Silver Redhorse and Shorthead Redhorse abundance were greater in narrow, longer rivers. Juvenile Lake Sturgeon abundance was positively correlated with longitude and river discharge. Mean species diversity and richness of large-bodied fish among all sites was 1.58 (0.36 SD) and 7.7 (2.6 SD). Species diversity was not significantly related to any of the variables used in the Generalized Linear Model; however, species richness was significantly related to maximum depth. This study demonstrated subtle differences in environmental variables affecting large-bodied fish at the landscape scale rather than those observed at the river scale.

Summary The goal of this study was to compare the possible locations, timing, and characteristics of potentially spawning shovelnose sturgeon (Scaphirhynchus platorynchus), blue sucker (Cycleptus elongatus), and associated species during the spring of 2007–2015 in the 149-km-long lower Wisconsin River, Wisconsin, USA, a large, shallow, sand-dominated Mississippi River tributary. A 5-km index station of two pairs of rocky shoals surrounded by sandy areas was electrofished for shovelnose sturgeon and blue sucker in a standardized fashion a total of 40 times from late March through mid-June, the presumed spawning period. On one date in 2008 and two dates in 2012, all rocky shoals and adjacent sandy areas in the lowermost 149 km of the river were also electrofished for both species. Shovelnose sturgeon and blue sucker appeared to spawn in the limited rocky areas of the river along with at least four other species: mooneye (Hiodon tergisus), quillback (Carpiodes cyprinus), smallmouth buffalo (Ictiobus bubalus), and shorthead redhorse (Moxostoma macrolepidotum), usually at depths of 0.8–2.0 m and surface velocities of 0.4–1.0 m/s. However, apparently spawning shovelnose sturgeon were found only on mid-channel cobble and coarse gravel shoals within a single 7-km segment that included the 5-km index station, whereas apparently spawning blue suckers were encountered on these same shoals but also more widely throughout the river on eroding bluff shorelines of bedrock and boulder and on artificial boulder wing dams and shoreline rip-rap. Both species showed evidence of homing to the same mid-channel shoal complexes across years. Blue sucker tended to concentrate on the shoals earlier in the spring than shovelnose sturgeon, usually from late April through mid-May at water temperatures of 8.0–15.5°C along with quillback and shorthead redhorse. In comparison, shovelnose sturgeon usually concentrated on the shoals from mid-May through early June at 13.5–21.8°C along with mooneye and smallmouth buffalo. Based on recaptures of tagged fish, at least some shovelnose sturgeon and blue sucker returned to the shoals at one-year intervals, although there was evidence that female blue sucker may have been more likely to return at two-year intervals. Most shovelnose sturgeon could not be reliably sexed based on external characteristics. Spawning shovelnose sturgeon ranged from 487 to 788 mm fork length, 500–2400 g weight, and 5–20 years of age, whereas spawning blue sucker ranged from 495 to 822 mm total length, 900–5100 g weight, and 5–34 years of age, although age estimates were uncertain. Females were significantly larger than males for both species although there was overlap. Growth in length was negligible for tagged and recaptured presumably spawning shovelnose sturgeon and low (3.5 mm/y) for blue sucker, suggesting that nearly all growth may have occurred prior to maturity and that fish may have matured at a wide range of sizes.

We explored tissue concentrations of polychlorinated biphenyls (PCBs), chlorinated pesticides, and relevant organochlorines and fish health in the following adult wild fish in the St. Clair River Area of Concern (Ontario, Canada): shorthead redhorse (Moxostoma macrolepidotum), yellow perch (Perca flavescens), and emerald shiner (Notropis atherinoides). We collected adult fish from sites within the river's industrial zone (Stag Island), a downstream site adjacent to Walpole Island (Chenal Ecarte), and an upstream reference site in Lake Huron in 2002/2003 and 2014. We tested for trends in tissue concentrations of organic contaminants across sites and over time; we assessed the potential effects of contaminants on morphological indicators of fish health across sites by year. Over the 12-year period, the tissue concentrations of most PCBs declined at the river sites, except for some non-legacy PCBs (PCB11 and 185), which increased in yellow perch at Stag Island, a new observation for fish in the St. Clair River AOC. There was little difference between the concentrations of calculated toxic equivalents (TEQs) of the Lake Huron and the St. Clair River fish in 2014, except for emerald shiners from Stag Island which had elevated ΣPCB and TEQs. Each fish species at all sites exceeded the Canadian tissue residue guideline for PCBs for the protection of mammalian wildlife consumers of aquatic biota, but fish-derived TEQs indicated little potential health risk to fish. Over time, hexachlorobutadiene and hexachlorobenzene concentrations increased in some fish at Stag Island by about 8- and 4-fold, respectively, whereas they decreased at other sampling locations. Principal Component Analysis followed by Linear Discriminant Analysis of the 2014 SHRH data suggested that although the fish separated by site, tissue concentrations of PCB and organochlorine contaminants did not have consistent relationships to the morphological health indicators, including egg production in females, which implied the absence of causative relationships.

Fishways are increasingly constructed to maintain longitudinal connectivity for fish in numerous river systems where migrations are interrupted by anthropogenic barriers, although there is a paucity of information on the biological effectiveness of fishways for most species. We evaluated fishway approach behaviour, and quantified attraction and passage efficiency of three catostomid species (silver redhorse Moxostoma anisurum, river redhorse M. carinatum and shorthead redhorse M. macrolepidotum) that undertake annual obligate spawning migrations through the Vianney-Legendre vertical slot fishway at the St. Ours Dam, in the Richelieu River, Quebec, Canada. Use of PIT tagging alone enabled quantification of attraction and passage efficiency and these were; 51, 17 and 50 % for attraction efficiency and passage efficiencies were 88, 50, and 69 % for silver, river, and shorthead redhorse, respectively. Silver redhorse had significantly shorter entrance delay and passage duration times than shorthead redhorse. Attraction efficiency was different among release locations for silver redhorse, and passage efficiency increased with size for shorthead redhorse. For all species, failure to ascend the fishway was most likely to occur before the second turning basin (before the 32 m mark) in the fishway (84 % of failures). Silver redhorse had significantly lower passage failure rates than river and shorthead redhorse. Activity patterns in the three species during fishway passage were different; crepuscular activity patterns were observed in shorthead and river redhorse, whereas silver redhorse activity peaked between 23:00 and 02:00 then decreased through the remainder of the day. To further evaluate fishway approach behaviour we fitted an additional sample of each species with external radio tags, although nearly all radio tagged individuals (n = 119) rapidly moved downstream upon release immediately post-tagging. Subsequently, our results were confounded by the behavioural impairments associated with external radio tagging and fallback. These results demonstrate the value of multispecies fishway evaluations and highlight the variation among individual species fishway performance within a single genus.

Associations between environmental variables and reproductive condition of six catostomid (family Catostomidae) species were evaluated in the Baraboo River, Wisconsin. Electrofishing and hoop net surveys conducted from Mar. to Jun. of 2001 and 2002 revealed white sucker (Catostomus commersoni) reached spawning condition first, followed by quillback (Carpiodes cyprinus) in both years. These two species were followed by the overlapping spawning times of spotted sucker (Minytrema melanops), golden redhorse (Moxostoma erythrurum), shorthead redhorse (M. macrolepidotum), and silver redhorse (M. anisurum). The first axis of a principal component analysis (PCA; based on six environmental variables) explaining 47% of the variation in the environmental variables represented water temperature, flow, and day of the year. The second axis explaining an additional 26% of variation depicted the magnitude of shorter-term changes in water temperature and flow. The best-fitting multinomial logit model to explain v...

Adult Black Redhorse (Moxostoma duquesnei) were seined from the Grand River, Ontario and artificially spawned in May 2007 and May 2008. Eggs hatched after 9–16 days at a mean temperature of 20°C, and after 11–25 days at a mean temperature of 17°C. Eggs did not develop fully at temperatures

We compared detection efficiency for three lengths (12, 23 and 32 mm) of half-duplex (HDX) passive integrated transponder (PIT) tags for both manual tracking and fixed array applications. In a stream we used a wand-type manual tracking antenna and determined that detection efficiency was considerably influenced by tag size (i.e., 20% for 12 mm, 43% for 23 mm, and 81% for 32 mm) and water depth. Vertical and horizontal read range also varied among tag sizes (lower for smaller tags) and orientation (12-mm and 23-mm tags oriented perpendicularly failed to read in the horizontal test). Using a fixed PIT array, we also compared the detection efficiency of the same three sizes of PIT tags in Shorthead Redhorse Moxostoma macrolepidotum released into a fishway. Again, detection efficiency increased with tag size: 12 mm = 55.8 ± 9.2% (mean ± SE), 23 mm = 91.0 ± 1.8%, and 32 mm = 97.0 ± 1.5%. When using PIT telemetry on smaller fish species and/or life stages, we suggest that researchers consider the tag s...

A shift from target species to ecosystem restoration has generated interest in developing fishways that are capable of passing entire fish communities. Although a number of multispecies fishways now exist in North America, evaluations of these fishways are lacking. We used a passive integrated transponder antenna array to quantify passage success and passage duration of fish using a vertical slot fishway (85 m in length, 2.65 m elevation rise, 12 regular pools and 2 turning basins) at a low head dam on the Richelieu River in Quebec, Canada. Fourteen of the 18 tagged species re-ascended the fishway, and passage efficiency was highly variable among species (range 25%–100%); however, it was >50% for five of the species well represented in this study (n > 10) (Atlantic salmon, channel catfish, smallmouth bass, walleye and white sucker). Passage duration was likewise highly variable both among and within species (e.g. 1.0–452.9 h for smallmouth bass, 2.4–237.5 h for shorthead redhorse). Although this fishway design was not uniformly successful in passing fish of all species, this study does reveal the species that have problems with ascent and provides an estimate on the time spent in the fishway that is an important component of passage delay. Such information could be used to inform future design refinements to facilitate passage of the entire assemblage with minimal delay. Copyright © 2012 John Wiley & Sons, Ltd.

Summary Understanding the trophic ecology of closely-related species is important for providing insight on inter-specific competition and resource partitioning. Although catostomids often dominate fish assemblages in lotic systems, little research has been conducted on their ecology. This study was developed to provide information on the trophic ecology of catostomids in several Iowa rivers. Food habits, diet overlap, and gill raker morphology were examined for highfin carpsucker Carpiodes velifer, quillback C. cyprinus, river carpsucker C. carpio, golden redhorse Moxostoma erythrurum, shorthead redhorse M. macrolepidotum, silver redhorse M. anisurum, and northern hogsucker Hypentelium nigricans sampled from four Iowa rivers (2009). Diet overlap among all species was calculated with Morista’s index (C). Food habit niche width was quantified with Levin’s index (B) and similarity in gill raker morphology was compared with analysis of covariance. Values from Morista’s index suggested significant overlap in the diets of highfin carpsucker and river carpsucker (C = 0.81), quillback and river carpsucker (C = 0.66), and shorthead redhorse and silver redhorse (C = 0.67). Levin’s index indicated that golden redhorse (B = 0.32), quillback (B = 0.53), and river carpsucker (B = 0.41) had the most generalized feeding strategies as their food niche widths were substantially wider than the other species. Gill raker length and spacing were positively correlated with the standard length of the fish for all species (gill raker length: r2 = 0.67–0.88, P ≤ 0.01; gill raker spacing: r2 = 0.63–0.73, P ≤ 0.01). Slopes of regression of gill raker length and spacing to standard lengths were significantly (P ≤ 0.05) different among species, indicating that rates of change in gill raker morphology with body length varied among species. Differences in gill raker morphology likely allow catostomids to partition resources and reduce competitive interactions.

Catostomids are among the most widespread and ecologically important groups of fishes in North America, particularly in large river systems. Despite their importance, little information is available on their population demographics and even less is known about factors influencing their population dynamics. The objectives of this study were to describe annual mortality, recruitment variation, and growth of eight catostomid species, and to evaluate the effects of discharge and temperature on year-class strength and growth in Iowa rivers. Catostomids were sampled from 3-km reaches in four nonwadable rivers during June–August 2009. Northern hogsucker, Hypentelium nigricans, golden redhorse, Moxostoma erythrurum, and shorthead redhorse, M. macrolepidotum, typically lived 6–8 years, had very stable recruitment, and had high total annual mortality (i.e., 40–60%). Golden redhorse exhibited the fastest growth of all species. Growth of northern hogsucker and shorthead redhorse was intermediate to the other catostomids. Highfin carpsucker, Carpiodes velifer, quillback, Carpiodes cyprinus, and white sucker, Catostomus commersonii, had high growth rates, low mortality (i.e., 25–30%), and relatively stable recruitment. River carpsucker, Carpiodes carpio, and silver redhorse, M. anisurum, had higher maximum ages (up to age 11), slower growth, lower total annual mortality (20–25%), and higher recruitment variability than the other species. Neither discharge nor temperature was strongly related to recruitment of catostomids. In contrast, several interesting patterns were observed with regard to growth. Species (e.g., carpsuckers, Carpiodes spp.) that typically consume prey items most common in fine substrates (e.g., chironomids) had higher growth rates in reaches dominated by sand and silt substrate. Species (e.g., northern hogsucker) that consume prey associated with large substrates (e.g., plecopterans) had much faster growth in reaches with a high proportion of rocky substrates. Temperature was weakly related to growth of catostomids; however, discharge explained a substantial amount of the variation in growth of nearly all species. Results of this study provide important information on the autecology of catostomids that can be used for comparison among species and systems. These data also suggest that connection of rivers with their floodplain is an important feature for catostomids in temperate river systems. Published in 2011 by John Wiley & Sons, Ltd.

In order to identify leech species prevalent in Lake St. Clair, Michigan, U.S.A,. and understand their effect on fish hosts, fish were collected during May 2006 and 2007 from Anchor Bay, Lake St. Clair in the Laurentian Great Lakes Basin. Throughout the study, 2,117 fish from 21 species were examined for the presence of leeches. Overall, 1,064 leeches were collected from 165 individual fish and identified morphologically. Hosts included the channel catfish, freshwater drum, northern pike, northern shorthead redhorse sucker, quillback sucker, rock bass, smallmouth bass, walleye, and yellow perch. Leeches attached to hosts had a prevalence of 7.79%, with a mean intensity of 6.45 leeches/infected fish and an abundance of 0.50 leeches/examined fish. Collected leeches were identified as Actinobdella pediculata (Glossiphonidae), Placobdella montifera (Glossiphonidae), and Myzobdella lugubris (Piscicolidae), which was the most commonly occurring species. The freshwater drum had the highest prevalence, m...

Summary Despite comprising a large portion of riverine fish biomass, very little demographic information is available for redhorse sucker (Moxostoma spp.) populations in Ontario (Canada). Information is presented on size and age structure, growth, and mortality of black redhorse (M. duquesnei), a threatened fish species, and shorthead redhorse (M. macrolepidotum) in the Grand River, Ontario. Estimates of body condition, adult mortality, longevity, and maximum attained length were very similar for both species. However, the more abundant shorthead redhorse reached maturity at a smaller size and younger age and grew at a slower rate than the black redhorse. Compared to populations in more southerly parts of its range, Grand River black redhorse grew more slowly, matured later and at a larger size, reached a higher maximum length and age, and was characterized by lower adult mortality rates. Reflective of its central location in the species range, the age and length characteristics of the Grand River population of shorthead redhorse were intermediate of, and overlapped with, other sampled populations.

Larval fishes were sampled in the Milk River, Missouri River drainage, Montana from May to August 2002, 2003 and 2004 to describe temporal spawning distribution in relation to spring discharge. Total larval catch-per-unit-effort (CPUE) in 2002 (28.9 fish/100 m3) was an estimated 29 times greater than in 2003 (0.99 fish/100 m3) and 16 times greater than in 2004 (1.78 fish/100 m3). In 2003 and 2004 more than one third of the total catch occurred before 12 June whereas in 2002, only 5% of the total catch occurred before 12 June. Marked differences in larval species composition were also observed between years, suggesting that a later peak in discharge may benefit some species and an earlier peak others. In 2002, when flows peaked later (at 77 m3 s−1), common carp Cyprinus carpio represented 37% of the total larval catch. Common carp were proportionally less abundant in 2003 (7.2%) and 2004 (1.4%) than in 2002. In 2004, when flows peaked (at 163 m3 s−1) 32 days earlier than in 2002 but only 15 days earlier than in 2003 (at 73 m3 s−1), shorthead redhorse Moxostoma macrolepidotum and suckers Catostomus sp. were the numerically dominant taxa. These results indicate that the timing, not necessarily the magnitude, of peak spring discharge may influence spawning success in the lower Milk River, as indicated by larval fish catches. Copyright © 2008 John Wiley & Sons, Ltd.

Fish surveys throughout the Wateree River in 2004–2005 documented the presence of 8 catostomid species—Carpiodes sp. cf. Cyprinus (quillback), Erimyzon oblongus (creek chubsucker), Ictiobus bubalus (smallmouth buffalo), Minytrema melanops (spotted sucker), Moxostoma collapsum (notchlip redhorse), M. macrolepidotum (shorthead redhorse), Scartomyzon rupiscartes (striped jumprock), and Scartomyzon sp. undescribed species (brassy jumprock)—but failed to document C. sp. cf. velifer (highfin carpsucker), Moxostoma sp. cf. Erythrurum (Carolina redhorse), or M. robustum (robust redhorse). Four native (quillback, spotted sucker, notchlip redhorse, and shorthead redhorse) and the nonnative small-mouth buffalo were collected in sufficient numbers to allow observations of unique aggregations. Based on time of year, expression of milt, presence of tubercles, and published thermal preferenda during spawning, we believe these aggregations were associated with spawning, although direct observations of spawning b...

Redhorse, Moxostoma spp., are considered to be negatively affected by dams although this assertion is untested for Canadian populations. One hundred and fifty-one sites in the Grand River watershed were sampled to identify factors influencing the distribution of redhorse species. Individual species of redhorse were captured from 3 to 32% of sites. The most widespread species were golden redhorse, M. erythrurum (30%) and greater redhorse, M. valenciennesi (32%), while river redhorse, M. carinatum, was only found along the lower Grand River. Redhorse were absent from the highly fragmented Speed River sub-watershed and upper reaches of the Conestogo River and the Grand River. Redhorse species richness was positively correlated to river fragment size and upstream drainage area. Generalized additive models (GAMs) were applied to evaluate the influence of river fragment length, connectivity and habitat on species distribution. Principal component analysis reduced habitat data to three axes representing: channel structure, substrate, and pool, riffle and run habitats (PC1); gradient and drainage area (PC2); and cover (PC3). GAMs indicate that PC2 was important for predicting black redhorse and greater redhorse site occupancy and PC1 was important for golden redhorse. River fragment length was important for predicting site occupancy for shorthead redhorse, but not other species.

Boat-electrofishing surveys and fishway monitoring were undertaken to describe the characteristics of redhorse (Moxostoma spp.) spawning runs in the Grand River, Muskegon River and Trent River. Spawning began in early May and was complete by mid-June. Timing of spawning varied among species, rivers, and years. Shorthead redhorse and silver redhorse spawned earlier and at lower water temperatures than black redhorse and river redhorse. Differences between rivers and years likely resulted from differences in the timing of suitable water temperatures and suitable flow levels, respectively. Spawning males were generally smaller, more numerous, and present in spawning areas earlier than females. While males reached sexual maturity at a younger age than females, there were no overall differences in the ages of spawning male and female redhorse.

Adult greater redhorse Moxostoma valenciennesi, were seined from the Grand River, Ontario, and artificially spawned in May 1997 and May 1998. Eggs hatched after 6–8 d at a mean temperature of 19 C. Eggs and larval development of 9–22-mm specimens are described. Ontogeny of larval greater redhorse was compared to that of other syntopic Moxostoma species from previously published studies, including river redhorse (M. carinatum), black redhorse (M. duquesnei), golden redhorse (M. erythrurum), shorthead redhorse (M. macrolepidotum), copper redhorse (M. hubbsi) and spotted sucker (Minytrema melanops). There was significant overlap between most meristic variables that were compared. However, the majority of greater redhorse (up to 18-mm) have myomere counts (27–33 pre-anal myomeres, 9–10 postanal myomeres and 39–42 total myomeres) that are different from other sympatric redhorse species and spotted suckers and may allow identification of greater redhorse as small as 9-mm.

Our understanding of biological design criteria to facilitate fishway passage design is limited, partially due to the lack of understanding of biological motivators, cues and constraints, as well as a lack of biological performance evaluations of structures once they are built. The Vianney-Legendre vertical slot fishway on the Richelieu River, Quebec, passes large numbers of migrating redhorse (Moxostoma spp.) upriver to spawning grounds each year. We evaluated the physiological capacity and relative swimming ability of three redhorse species (M. anisurum, M. carinatum, M. macrolepidotum, silver, river and shorthead redhorse respectively) to determine how these biotic factors relate to variation in fishway passage success and duration. Shorthead redhorse had higher maximum metabolic rates and were faster swimmers than silver and river redhorse. River redhorse recovered their lactate and glucose concentrations more quickly than silver and shorthead redhorse, and river redhorse were second in terms of metabolic recovery and swim speed. Additionally, fish sampled from the top of the fishway had nearly identical lactate, glucose and pH values compared to control fish. Using passive integrated transponders in 2010 and 2012 we observed that passage success and duration was highly variable among redhorse species and was not consistent among years suggesting that other factors such as water temperature, timing of the study and river flows modulate passage success. Clearly additional research is needed to understand how organismal performance, environmental conditions, and other factors (including abundance of conspecifics and other co-migrants) interact with fishway design features to dictate which fish will be successful and to inform design of future fishways. Our research suggests that there may be an opportunity for a rapid assessment approach where manual chasing and sampling of fish from the top of the fishway are used to determine which species (or sizes of fish) are exceeding their physiological capacity during passage. Fil: Hatry, Charles. Carleton University; Canadá Fil: Thiem, Jason D.. Carleton University; Canadá Fil: Binder, Thomas R.. Carleton University; Canadá Fil: Hatin, Daniel. Ministère des Ressources Naturelles et de la Faune; Canadá Fil: Dumont, Pierre. Ministère des Ressources Naturelles et de la Faune; Canadá Fil: Stamplecoskie, Keith M.. Carleton University; Canadá Fil: Molina, Juan Manuel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Bahia Blanca. Instituto de Ciencias Biologicas y Biomedicas del Sur; Argentina. Carleton University; Canadá Fil: Smokorowski, Karen E.. Fisheries and Oceans Canada. Great Lakes Laboratory for Fisheries and Aquatic Sciences; Canadá Fil: Cooke, Steven J.. Carleton University; Canadá

Gill nets and electrofishing were utilized in the Missouri River below Fort Randall Dam, South Dakota to sample river carpsucker (Carpiodes carpio), shorthead redhorse (Moxostoma macrolepidotum), and shovelnose sturgeon (Scaphirhynchus platorynchus). Shorthead redhorse, shovelnose sturgeon, and river carpsucker all exhibited significant monthly variation in mean relative weight (Wr) during at least one sample year (P < 0.05). In general, Wr values for all species tended to be highest early in the year followed by a steady decline to a seasonal low during the later sample months. Shorthead redhorse and river carpsucker catch per unit effort (CPUE) followed a similar bimodal pattern of spring and fall peaks with lower CPUE during summer. Catch per unit effort of shovelnose sturgeon was highest in the fall at the lower site (P < 0.001, October 1998; P = 0.006 and P = 0.009, September and October 1999) with no differences found at the upper site. Within-site variations in size generally were not sign...

American Electric Power’s Conseville Station and Muskingum River Plant, located on the Muskingum River in southeastern Ohio, utilize once-through cooling for seven (combined) generating units. Both facilities had approved 316(a) variances that required maintenance of a baseline fully-mixed downstream temperature of 31.6°C (88.9°F). Fish sampling conducted during critical conditions in Summer 1993 indicated the presence of thermally-sensitive redhorse suckers ( Moxostoma sp.) at river temperatures >32.2°C (90.0°F). Because the assumed upper tolerance limit for redhorse suckers (31.6°C) was extrapolated from field observations, we determined the actual thermal tolerance of suckers using fish collected locally. During September 1996 golden and shorthead redhorses were collected from the nearby Walhonding River. The short-term upper thermal tolerances were determined by the ultimate upper incipient lethal temperature (UUILT) and the critical thermal maximum (CTM) endpoints. For shorthead redhorse the calculated UUILT was 33.3°C (91.9°F), and the CTM was 35.1°C (95.2°F). For golden redhorse a similar CTM was obtained; however, a reliable UUILT could not be extrapolated due to procedural problems. The results of these tests played a role in Ohio EPA approving a higher fully-mixed downstream limit. This study demonstrates the value of obtaining thermal tolerances experimentally when assumed tolerance values are considered suspect.

The presence of neutralizing antibodies against viral hemorrhagic septicemia virus (VHSV-IVb) was investigated in sera of 13 fish species collected from Lake St. Clair, Michigan, USA, a VHSV-endemic water body. We tested 297 sera collected May 2004-June of 2010, using a complement-dependent 50% plaque neutralization test (50% PNT). Neutralizing antibodies were detected in 23% (67/297) of the samples. The highest overall antibody prevalence (85%, 34/40) and mean positive antibody titer (12,113 ± 11,699 SD) were detected in muskellunge (Esox masquinongy). Antibodies were also detected in 50% (15/30) of sampled northern pike (E. lucius), 25% (15/61) of freshwater drum (Aplodinotus grunniens), and 7% (3/41) of smallmouth bass (Micropterus dolomieu). All sera from channel catfish (Ictalurus punctatus), lake sturgeon (Acipenser fulvescens), quillback (Carpiodes cyprinus), rock bass (Ambloplites rupestris), shorthead redhorse (Moxostoma macrolepidotum), silver redhorse (M. anisurum), walleye (Sander vitreus), white perch (Morone americana), and yellow perch (Perca flavescens) were negative. Antibodies in one or more fish species were detected in all sampling years (2004, 2006, 2007, 2009, and 2010), whereas in parallel sampling periods, VHS virus was detected only in 2006 and 2009. Our results suggest the continued presence of VHSV-IVb in the Lake St. Clair ecosystem, and underscore the importance of assessing immune responses of fish populations to determine prior virus exposure.

Examination of some freshwater and brackishwater (estuarine) fishes in South Carolina in October 2009 yielded, in addition to other parasites, 2 little-known nematode species identified as Dichelyne fastigatus Chandler, 1935 (Cucullanidae), from the red drum, Sciaenops ocellatus (Linnaeus), from an estuary, and Rhabdochona ovifilamenta Weller, 1938 (Rhabdochonidae), from the shorthead redhorse, Moxostoma macrolepidotum (Lesueur), from Lake Moultrie. Light and scanning electron microscopy (the latter used for the first time for these species) made it possible to describe several important, but previously unreported, taxonomic features in D. fastigatus, such as the location of the excretory pore and deirids, the shape of deirids and a gubernaculum, the shape and size of eggs, the presence of precloacal ventral oblique muscle bands, and 11 pairs of caudal papillae and a pair of phasmids. It distinctly differs from the most similar Dichelyne cotylophora (Ward and Magath, 1917), a parasite of North American freshwater percids, in the number and arrangement of postanal papillae and by a markedly elevated cloacal region. Records of Dichelyne lintoni Barreto, 1922, from S. ocellatus probably concern D. fastigatus. Examination of R. ovifilamenta revealed a high degree of morphologic and biometric variability in this species. Based on our analysis, Rhabdochona laurentiana Lyster, 1940 , Rhabdochona milleri Choquette, 1951, and Rhabdochona catostomi Kayton, Kritsky, and Tobias, 1979, are synonymized with R. ovifilamenta Weller, 1938, typically a parasite of North American catostomids.

The distribution of fishes in Dauphin Lake, a large, shallow, turbid, prairie lake in west-central Manitoba, was examined using gillnets. Catch per unit effort was used to assess differences in distribution thai may be attributed lo year, season, lake zone (inshore, offshore), substratum, water depth, water temperature, turbidity and presence of other fish species. Although 13 species were caught, only the distributions of the six most abundant was analysed. Variation in number of species caught was attributed mainly to lake zone, water depth and water temperature. White sucker (Catastomus commersoni) distribution can be explained by zone and temperature. Shorthead redhorse (Moxostoma macrolepidotum) catches were related to depth and temperature. Cisco (Coregonus artedii) catches varied with year, zone and temperature. Variances in northern pike (Esox Indus) distribution reflected year and zone. Walleye (Stizostedkm vitreum) varied with year, depth and temperature and differences in the catches of yellow perch (Pertaflurescens) were attributed to year, depth, temperature and turbidity. They were also positively correlated to the numbers of northern pike caught.

Relative abundance of fishes in different habitat types and sampling areas of a reservoir in eastern Wyoming was assessed with experimental gill nets during summer 1989. Seven of 12 species captured in the gill nets were numerous enough to enable statistical evaluation: quillback (Carpiodes cyprinus), common carp (Cyprinus carpio), walleye (Stizostedion vitreum), gizzard shad (Dorosoma cepedianum), shorthead redhorse (Moxostoma macrolepidotum), channel catfish (Ictalurus punctatus), and yellow perch (Perca flavescens). All seven species were significantly more numerous in samples from littoral and offshore bottom areas than in samples from offshore surface areas throughout the summer. Common carp and walleye were significantly more abundant in the upstream portion of the reservoir throughout the summer, whereas quillback, gizzard shad, shorthead redhorse, and channel catfish were more abundant in the upstream portion during early summer.

17alpha-ethynylestradiol (EE2), a synthetic estrogen prescribed as a contraceptive, was measured in Shorthead Redhorse Suckers (ShRHSs) (Moxostoma macrolepidotum) collected near a wastewater treatment plant (WWTP) in the St. Clair River (Ontario, Canada). We detected EE2 in 50% of the fish samples caught near the WWTP (Stag Island), which averaged 1.6+/-0.6ng/g (wet weight) in males and 1.43+/-0.96ng/g in females. No EE2 was detected in the samples from the reference site (Port Lambton) which was 26km further downstream of the Stag Island site. Only males from Stag Island had VTG induction, suggesting the Corunna WWTP effluent as a likely source of environmental estrogen. EE2 concentrations were correlated with total body lipid content (R(2)=0.512, p

The shorthead redhorse (sr) Moxostoma macrolepidotum is endemic in North America, while in Canada the copper redhorse (cr) Moxostoma hubbsi is classified as endangered. A commercial heterologous carp vitellogenin (VTG) sandwich ELISA underestimates VTGs in these species. Hybrid ELISAs, using anti-carp VTG antibodies and purified sr- and cr-VTGs as standards, were validated to measure VTGs in plasma and surface mucus of redhorse species. The hybrid ELISAs showed good precision, sensitivity and accuracy. Following induction with beta-estradiol 3-benzoate (E2B), levels of plasma VTG (mean+/-SEM) in male sr increased from 2.7+/-1.5 microg/ml to 16.5+/-2.2mg/ml. In immature cr, plasma VTG increased to 70.1+/-13.8 mg/ml after induction, from an initial value of 37.7+/-51.0 microg/ml. Levels of VTG in mucus from E2B-injected fish were highly correlated (p0.0001) with levels in plasma, but not in a non-induced mature female. Hybrid assays are a good compromise between homologous and heterologous assays, especially for small-bodied or endangered fish species. The performance of the hybrid assays strongly suggests they could be used to determine exposure of these species to estrogenic contaminants and contribute to restoration efforts of the copper redhorse.

Vitellogenin (VTG), the egg yolk precursor protein, was purified from plasma of estradiol-3-benzoate (E2B)-treated male shorthead redhorse (Moxostoma macrolepidotum) and immature copper redhorse (Moxostoma hubbsi) by a two-step chromatographic procedure without precipitation. Intact VTGs appeared as dimers with apparent molecular masses, determined by gel filtration, of approximately 425 kDa (copper redhorse) and approximately 450 kDa (shorthead redhorse). In native polyacrylamide gel electrophoresis (PAGE), dimeric redhorse VTGs appeared as a 520 kDa band. Both VTGs were reduced to a single monomer of approximately 150 kDa in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) under reducing and nonreducing conditions, indicating that monomers are not linked by disulfide bonds in the dimer form. The purified proteins were characterized as phospholipoglycoproteins. Isoelectric focusing of both VTGs revealed components with isoelectric points ranging from 5.3 to 6.0, suggesting charge heterogeneity. The amino acid composition of both VTGs contains a high proportion of nonpolar amino acids and was similar to those of other teleosts. An antibody developed against carp (Cyprinus carpio) VTG showed cross-reactivity with VTG from both redhorse species. Using this antibody, VTG was detected in plasma and surface mucus of E2B-treated redhorse. This is the most extensive report on purification and characterization of vitellogenin from catostomidid species.

Lissorchis macropharynx (Digenea: Lissorchiidae) is described from the shorthead redhorse, Moxostoma macrole-pidotum (LeSueur) (Catostomidae) from the Assiniboine River drainage of southern Manitoba. The species is morphologically similar to Lissorchis hypentelii in possessing a similar body shape (widest at the ovarian region and a relatively long hindbody), a distinctly trilobed and relatively posteriorly situated ovary, and in the distribution of the vitellaria. It differs from L. hypentelii and all other lissorchiids in possessing a massive pharynx that is generally equal in length to or longer than the oral sucker and almost as deep as the cervical region of the body it occupies, a protruding acetabular region with an aspinose ridged/folded and grooved anterior surface, and a massive cirrus sac that reaches the level of the ovary. Museum specimens of Lissorchis spp. from M. macrolepidotum from other drainages in Manitoba and Wisconsin were also identified as L. macropharynx.

Shorthead redhorse eggs hatched 8 days after fertilization at a mean temperature of 15.6 C. The total length (TL) of newly hatched larvae averaged 10.0 mm (range, 9.3–10.4 mm); their standard (notochord) length averaged 9.4 mm (range, 8.7–9.9 mm). They were melanophore-free, had slightly upturned urostyles, and incomplete mouths. Melanophores appeared for the first time in larvae of 10.2 mm TL. Fin rays were visible in caudal, dorsal, pectoral, anal, and pelvic fins by 12.9, 15.8, 16.0, 16.7, and 18.8 mm TL, respectively. Transformation of shorthead redhorse to the mesolarval phase occurred by 12.4 mm TL and to metalarval phase by 16.2 mm TL. Protolarvae of the shorthead redhorse can be distinguished from those of northern hog sucker (Hypentelium nigricans) from the Susquehanna River by their smaller standard (notochord) length and larger postanal length as percentages of TL, and their fewer preanal myomeres. Shorthead redhorse mesolarvae lack the melanophore-free area between the eyes found in n...

Larval fish drift in the rocky-bottomed Susquehanna River (northeastern Pennsylvania) was investigated during 1974-1975. Near SSES (Susquehanna Steam Electric Station) at least 18 species of drifting larvae were collected by nets mounted on a stationary boat or by pumping. Maximum densities of 15.4 and 27.1 larvae/10 m3 were found in June 1974 and 1975, respectively. Quillback, Carpiodes cyprinus (56%), minnows (25%), and carp, Cyprinus carpio (14% of the total) were the most abundant larvae caught in 1974 by pumping. The few larvae that drifted during the day were mostly near the bottom. Large numbers of quillback, white sucker (Catostomus commersoni), shorthead redhorse (Moxostoma macrolepidotum), and tessellated darter (Etheostoma olmstedi) larvae drifted near the river surface at night. Drift was maximum at about 2400 h. Overall, the day/night drift ratio was 1/3.8. In 1974 at Falls, the control station upstream of SSES and several intervening coal mine effluents, maximum density of drifting ...

Larval phases of the longnose sucker (Catostomus catostomus) and golden redhorse (Moxostoma erythrurum) are described and compared with their congeners, the white sucker (C. commersoni) and shorthead redhorse (M. macrolepidotum). Catostomus catostomus has a greater head length and eye diameter than C. commersoni through all developmental phases. Catostomus catostomus also has a smaller posterior gas bladder chamber, relative to the anterior chamber, than C. commersoni. Moxostoma erythrurum averages fewer total myomeres (41 versus 44) than its congener and has greater preanal lengths, head lengths, and eye diameters. Larvae of C. catostomus and M. erythrurum are compared with characters presented in existing keys to larval catostomids to help determine if those characters are satisfactory for separation of sucker genera. Five different body measurements are allometrically related to total length in both species.

The incidence of attack by the sea lamprey (Petromyzon marinus) was studied on freshwater teleosts of similar and different size. Splake (Salvelinus namaycush × Salvelinus fontinalis), carp (Cyprinus carpio), and white suckers (Catostomus commersoni) were attacked a significantly greater number of times than lake whitefish (Coregonus clupeaformis), burbot (Lota lota), shorthead redhorse suckers (Moxostoma macrolepidotum), and brown bullheads (Ictalurus nebulosus). Lampreys rarely preyed upon walleye (Stizostedion vitreum vitreum). Most attacks occurred between the head and caudal peduncle below the lateral line and particularly in the region behind the pectoral fins. Lampreys attacked the largest individuals of any species more frequently than the smaller representatives. The presence of lampreys on a fish did not further the incidence of attack on that fish. None of the species of fish appeared to avoid lamprey attacks, nor did they avoid fish on which lampreys were attached. Only rarely were fish observed to dislodge lampreys.

Shorthead redhorse were observed spawning on 17 and 18 May 1976 in Big Rock Creek, Illinois, at 16 C in a manner similar to that described for other redhorse species. Spawning behavior and reproductive characteristics are described for the species.

Catch rates for all species combined were higher in hoop nets baited with soybean cake than in unbaited hoop nets. However, baited and unbaited nets differed in the fish species for which they were most selective. Significantly more common carp (Cyprinus carpio), channel catfish (Ictalurus punctatus), smallmouth buffaloes (Ictiobus bubalus), and bluegills (Lepomis macrochirus) were caught in hoop nets baited with soybean cake than in unbaited nets, but unbaited nets caught more flathead catfish (Pylodictis olivaris), shorthead redhorse (Moxostoma macrolepidotum), black crappies (Pomoxis nigromaculatus), and freshwater drum (Aplodinotus grunniens). Abundance of these species may influence the choice of baited or unbaited hoop nets and mesh size. All of our nets were set parallel with the current with the mouth facing downstream.