Differences in Species Composition and Feeding Ecology of Catostomid Fishes in Two Distinct Segments of the Missouri River, North Dakota, U.S.A.

In 1997 and 1998, we sampled the Missouri River, North Dakota to determine if anthropogenic disturbances had influenced catostomid species composition and feeding ecology. We compared two distinct river segments, the Missouri River between the mouth of the Yellowstone River and Lake Sakakawea (the Yellowstone–Sakakawea segment (YSS)), a moderately altered segment and the Missouri River between Garrison Dam and Lake Oahe (the Garrison–Oahe segment (GOS)), a highly altered segment. The segments exhibited greatly different sucker communities. Bigmouth buffalo, Ictiobus cyprinellus, smallmouth buffalo, Ictiobus bubalus, and river carpsucker, Carpiodes carpio, represented 94% of the sucker catch in the YSS, whereas in the GOS, white sucker, Catostomus commersoni, and longnose sucker, Catostomus catostomus, constituted 98% of the sucker catch. In the YSS, high zooplankton densities led to greater sucker zooplanktivory and food niche overlap than in the GOS. Intense anthropogenic disturbances to the GOS are associated with the differences in sucker species composition, prey density and composition, and sucker feeding ecology between the two segments.     

Tumors in fish from the Detroit River

A fish tumor survey was conducted in the Lower Detroit River during 1985 to 1987. Five species of fish were collected from sediment deposition zones and were examined for neoplasia. Neoplasms and related lesions were found in bullhead (Ictalurus nebulosus), walleye (Stizostedion vitreum), redhorse sucker (Moxostoma, sp), white sucker (Catostomus commersoni), and bowfin (Amia calva). Overall, 8.2 percent of the fish examined had oral/dermal lesions and 10.1 percent had liver lesions. Liver and skin tumors were found to be age-related in bullheads and size-related in walleye. Based on the fish surveyed, the incidence of tumors in fish from the Detroit River was similar to that observed in other chemically contaminated waterways.     

The effects of pulp mill effluent on the sex steroid binding protein in white sucker (Catostomus commersoni) and longnose sucker (C catostomus)

The objective of this study was to characterize the effects of pulp mill effluent on the properties of the sex steroid binding protein (SBP) in the plasma of white sucker (Catostomus commersoni) and longnose sucker (C. catostomus). SBPs which specifically bind estradiol and testosterone with high affinity (k(D) approximately 3 nM) and low capacity (B(max) approximately 73-81 nM) were identified in both species. Subsequent studies determined if the properties of the SBP in white sucker exposed to bleached kraft mill effluent (BKME) at Terrace Bay, ON, and in longnose sucker exposed to BKME at Grande Prairie, AB. differed from appropriate reference fish. There were no effects of BKME exposure on the binding affinity (k(D)) of the SBP in either species, but there was a significant increase in the binding capacity (B(max)) of longnose sucker SBP exposed to BKME. The livers of nai;ve white sucker exposed to effluent at Terrace Bay or a bleached sulfite/groundwood mill in Edmundston, NB, rapidly accumulated compounds of differing hydrophobicity that bound to both the white sucker and goldfish (Carassius auratus) SBP. Conversely, there was reduced accumulation of SBP ligands in the bile of effluent-exposed fish. We have demonstrated that constituents present within pulp mill effluent bind to both the white sucker and goldfish SBP, and that native species residing downstream of pulp mill effluents may experience modifications in the properties of their SBP.     

Growth chronologies of white sucker, Catostomuscommersoni, and lake trout, Salvelinusnamaycush: a comparison among lakes and between trophic levels

A growth chronology index was used to determine whether changes in ecosystem structure and function in lakes could be associated with fish growth histories. Growth chronologies were compared for white suckers, Catostomus commersoni, from Little Moose (oligotrophic), Oneida (eutrophic), and Cayuga (mesotrophic) lakes (New York) from opercular bone growth increments, and for lake trout, Salvelinus namaycush, from Little Moose Lake using otolith growth. The longevity of these species allowed the development of chronologies from 17 to 33 years in length using only contemporary collections. We used these chronologies to examine whether fish growth histories could be used as an index for ecosystem-scale changes. Specifically, we examined whether zebra mussel, Dreissena polymorpha, invasion in Oneida and Cayuga lakes in the early 1990s, and treatment of sewage effluent from dwellings around Little Moose Lake beginning during the late 1980s could be detected in white sucker and lake trout growth chronologies. White sucker growth in Oneida and Cayuga Lakes did not differ before and after zebra mussel invasions. Neither white sucker nor lake trout growth chronologies from Little Moose Lake reflect changes in growth expected with reduced productivity levels associated with improved sewage treatment. Growth chronologies of these two species did not detect the ecosystem-scale changes that occurred in the study lakes.     

Metacercariae of Diplostomum spathaceum in the eyes of fishes from Yellowstone Lake, Wyoming

Fish were collected from Yellowstone Lake, Wyoming (USA). Metacercariae of Diplostomum spathaceum was found in the lens of 11 of 12 longnose suckers (Catostomus catostomus). The mean number of metacercariae per sucker was 59 and the average age of the fish was 11.6 yr. There was no correlation between age and intensity of parasites (r = 0.24). Of 10 cutthroat trout (Salmo clarki) examined, there were metacercariae present in six. The metacercariae were found outside of the lens tissue in the trout; they occurred in the vitreous humor and the retina. These may be a different species from those found in the suckers.     

Fish shoal composition: mechanisms and constraints

Observations were made on three fish species (banded killifish (Fundulus diaphanus), golden shiner (Notemigonus crysoleucas) and white sucker (Catostomus commersoni)) in a temperate lake (New Brunswick, Canada) in order to investigate the relationship between shoal choice behaviour of individual fishes and shoal composition. Encounters between shoals were observed to take place every 1.1 min per shoal and an encounter lasted 3.7 s on average. The duration of shoal encounters was influenced by shoal size but not by differences between shoals in either body length or species. Conversely, the outcome of shoal encounters (i.e. ences between shoals in either body length or species. Conversely, the outcome of shoal encounters (i.e. whether or not an individual changes shoal) was influenced by body length and species differences but not by shoal size. Together, these results suggest that encounter duration itself is unlikely to have an important influence on encounter outcome. The collection of ten entire fish shoals showed that they were assorted by species and body length. A simulation model demonstrated that individual shoal choice behaviour alone could account for the generation and maintenance of the observed levels of size assortedness of shoals without invoking the existence of other sorting mechanisms such as differential swimming speeds. However, the generation of species assortedness was not predicted by the model. Furthermore, our data suggest that fish density acts as a constraint on shoal choice, influencing both shoal size and composition. This work has implications for studies on information transfer and reciprocal altruism within populations.     

The role of trophic bottlenecks in stunting: a field test of an allocation model of growth and reproduction in yellow perch, Perca flavescens

Synopsis Stunting in freshwater fish populations may be due to low availability of one or more prey components within their diet. If the limiting prey constitute a trophic level (i.e. zooplankton, benthos, or fish), we define the phenomenon as a trophic bottleneck. Growth of a non-stunted population of yellow perch, Perca flavescens, was simulated using an allocation model based on reported ontogenetic shifts in diet (planktivory to benthivory to piscivory). The model was then perturbed by limiting the available ration individually for each of the three feeding types. The resulting simulated growth curves all reflected lower growth rates than the unperturbed state and the shape of the curve differed between the limited food types. Only the reduced benthic ration produced a simulated growth that matched that observed for the stunted yellow perch of Lac Hertel (Québec). To test the hypothesis that benthic ration was limiting growth in Lac Hertel, all the fish species in the lake were sampled for diet composition and total length at age. We predicted that species feeding upon benthic invertebrates should exhibit the slow growth characteristic of stunting (based on the results of the allocation model). Of the seven fish species found in Lac Hertel, four were stunted: yellow perch, pumpkinseed, Lepomis gibbosus, rock bass, Ambloplites rupestris, and brown bullhead, Ictalurus nebulosus. Three species were non-stunted: northern pike, Esox lucius, golden shiner, Notemigonus crysoleucas, and white sucker, Catostomus commersoni. All stunted species fed on benthic invertebrates and all non-stunted species, except the white sucker, did not feed upon benthos. The prediction of the allocation model was thus supported.     

Sodium and potassium ATPase of the teleost fish Catostomus commersoni. Sequence, protein structure and evolutionary conservation of the alpha-subunit.

The alpha-subunit of a Na+/K+ ATPase has been cloned by analysing a lambda gt11 library constructed from polyA+ RNA from the hypothalamic region of the teleost fish Catostomus commersoni (white sucker). The cDNA clone consists of 3853 bp and predicts a protein of 1027 amino-acid residues. Alignment of the sucker sequence with protein sequences previously published for alpha-subunits from various species reveals a high degree of homology throughout the entire sequence containing five potential sites for N-glycosylation, a phosphorylation site and a site for binding fluorescein 5'-isothiocyanate (FITC). A hydropathy profile predicts a secondary structure of the Na+/K+ ATPase alpha-subunit with at least eight membrane-spanning domains. Northern and southern blot analyses suggest the existence of two distinct Na+/K+ ATPase alpha-subunit genes in the sucker genome.     

Temperature preference and tolerance of hybrid carp (female grass carp,Ctenopharyngodon idella x male bighead,Aristichthys nobilis)

Synopsis This study examined the effects of various pH values on sperm motility times of white suckers,Catostomus commersoni, from two artificially acidified lakes in the Experimental Lakes Area (ELA), northwestern Ontario. White sucker sperm were active (motile) in water at all pH values tested (3.0–7.0). The maximum sperm motility time was 76.9 seconds and the minimum time was 51.9 seconds. Sperm motility times of fish from Lake 302N were similar to those of fish from Lake 223 at all pH values except pH 5.0 and 5.5. At these two pH values, sperm motility times of Lake 223 fish were longer than those of Lake 302N fish. In both lakes sperm motility at ambient lake pH levels (Lake 223 + 5.1, Lake 302N + 6.3) were similar to those at pH 7.0. Motility times of all fish tested were within the range of time during which fertilization normally occurs, indicating that reproductive failures in Lake 223 were probably not caused by impairment of sperm motility times.     

Physiological stress response of Mountain Whitefish (<Emphasis Type="Italic">Prosopium williamsoni</Emphasis>) and White Sucker (<Emphasis Type="Italic">Catostomus commersoni)</Emphasis> sampled along a gradient of temperature and agrichemicals in the Oldman River,Alberta

Species differences in tolerance to environmental stressors can contribute to differences in species distribution and abundance along river gradients. Climate change and intensive agriculture are likely to have major effects on fish populations in temperate zones, yet understanding of the interactions between temperature and chemical stressors on fish physiology is limited. The objective of this study was to compare the stress responses of the Mountain Whitefish, (Prosopium williamsoni, a cold-water fish) and White Sucker (Catostomus commersoni, a cool-water fish), along a temperature and pesticide gradient in the Oldman River, Southern Alberta in spring and summer. Fish were seined, placed into an enclosure, and plasma cortisol, glucose, liver glycogen, and condition factor were measured. Plasma acetylcholinesterase (AChE) activity was used as an indicator of exposure to organophosphate and carbamates pesticides. Whitefish had lower plasma AChE activity and lower liver glycogen reserves compared to suckers at all sites and all sampling times but the differences in plasma cortisol were not species-specific and there were no differences in plasma glucose levels, except at one site. Plasma cortisol increased, and plasma glucose decreased along a downstream river gradient in whitefish in both spring and summer; in sucker only plasma cortisol fluctuated and only in the summer. Liver glycogen decreased along the river gradient in both species at both seasons. Our study detected important species-specific differences in AChE activities and responses of the physiological stress axis, suggesting that whitefish are more sensitive to temperature and pesticide stress than suckers.     

Evolutionary and physiological variation in cardiac troponin C in relation to thermal strategies of fish

Striated muscle contraction is initiated when troponin C (TnC) binds Ca(2+), which activates actinomyosin ATPase. We investigated (i) the variation between cardiac TnC (cTnC) primary structure within teleost fish and (ii) the pattern of TnC expression in response to temperature acclimation. There were few differences between rainbow trout (Oncorhynchus mykiss), yellowfin tuna (Thunnus albacares), yellow perch (Perca flavescens), goldfish (Carassius auratus), white sucker (Catostomus commersoni), and icefish (Chaenocephalus aceratus) in cTnC amino acid sequence. No variation existed in the regulatory Ca(2+)-binding site (site 2). The site 3 and 4 substitutions were limited to residues not directly involved in Ca(2+) coordination. Fish cTnC primary structure was highly conserved between species (93%-98%) and collectively divergent from the highly conserved sequence seen in birds and mammals. Northern blots and polymerase chain reaction showed that thermal acclimation of trout (3 degrees, 18 degrees C) did not alter the TnC isoform pattern. While cardiac and white muscle had the expected isoforms-cTnC and fast troponin C (fTnC), respectively-red muscle unexpectedly expressed primarily ftnC. Cold acclimation did not alter myofibrillar ATPase Ca(2+) sensitivity, but maximal velocity increased by 60%. We found no evidence that TnC variants, arising between species or in response to thermal acclimation, play a major role in mitigating the effects of temperature on contractility of the adult fish heart.     

Metazoan arasites of fish from the Smallwood Reservoir, Labrador, Canada

Three-hundred and thirty-two fish of eight species (5 Salmo salar , 68 Salvelinus fontinalis , 32 S. namaycush , 102 Coregonus clupeaformis , 1 Prosopium cylindraceum , 107 Esox lucius , 14 Catostomus catostomus , 3 Couesius plumbeus ) from the Smallwood Reservoir, Labrador, Canada, were examined for metazoan parasites, using conventional parasitological techniques.
Fifteen genera of parasites were recovered (two of Monogenea, two of Digenea, four of Cestoda, three of Nematoda, two of Acanthocephala and two of Copepoda), these including seven new host records.
Significant differences were noted in the prevalence of the various parasites which were common to the different species of fish examined. No differences were recorded in the parasite burden of male and female fish. There was no correlation between the number of parasite species per infected fish and host age except in the case of Salvelinus namaycush . Food items of the fish examined were also noted.     

Pyloric caecal morphology of brook charr,Salvelinus fontinalis,in relation to diet

Synopsis Brook charr, Salvelinus fontinalis, shifts its diet from zoobenthos to pelagic prey when living sympatrically with white sucker, Catostomus commersoni, in lakes of the Laurentian Shield. We tested the hypothesis that this diet difference would have a significant impact on their pyloric caecal morphology in 5 lakes containing allopatric brook charr populations and 6 other lakes containing both brook charr and white sucker. We observed that the mean length of the most posterior caecum of charr was significantly greater in sympatry than in allopatry (X ± 1 SD: 9.91 ± 1.12 mm versus 8.44 ± 0.67 mm). This is equivalent to an increase of 18% of total pyloric caecal mass (dry weight) in sympatric brook charr. These results indicate that this response to differences in diet, well known in birds, also occurs in fish.     

Segregation by species and size classes of rainbow trout,Salmo gairdneri,and Sacramento sucker,Catostomus occidentalis,in three California streams

Synopsis The hypothesis that Sacramento suckers, Catostomus occidentalis, compete with rainbow trout, Salmo gairdneri, for space in streams was examined by measuring microhabitat utilization of both species in three California streams. Two streams were similar in most respects except one contained only trout and one contained trout and a large population of suckers. The third stream, formed by the union of the first two, contained trout and a small population of suckers. The species overlapped in five of the six microhabitat variables measured: maximum depth, mean water column velocity, focal point velocity, surface water velocity, and substrate type. However, the species had strong vertical segregation; there was little overlap between species in focal point depth. Mean focal point velocities were also significantly different. Suckers roamed over and generally remained in contact with the bottom while trout held position in the water column. Microhabitat utilization by trout in the stream without suckers was similar to in the stream with a higher sucker density. Differences in microhabitat utilization by trout between the third stream and the other two was attributed to the larger size of the third stream. Both sucker and trout showed a similar within-species segregation of size classes - fish under 50 mm in length sought shallow water. Size-specific trends indicated ontogenic shifts in resource utilization which reduced overlap within species. These results suggest that competition for space between trout and suckers was not a major factor regulating microhabitat utilization of trout, although the possibility that larger suckers may displace small trout needs further study.     

Spatial and temporal variation of fish communities in secondary channels of the San Juan River, New Mexico and Utah

Spatial and temporal variation of fish communities in four secondary channels of the San Juan River between Shiprock, NM and Bluff, UT were investigated from July 1993 through November 1994. Fish abundance and habitat availability data were collected to determine if physical attributes of sites influenced spatial and temporal variation in their fish communities. Stability of habitat was shown to positively influence the stability of the fish community. Analysis of variance revealed greater spatial than temporal variation in the abundance of red shiner, Cyprinella lutrensis, fathead minnow, Pimephales promelas, and flannelmouth sucker Catostomus latipinnis, while speckled dace, Rhinichthys osculus showed greater temporal variation. Ordination, using detrended correspondence analysis, revealed variation in fish communities by site, date, and sample year. Spatial variation was greatest during low-flow periods when the greatest differences in habitat among the four sites occurred. Spring runoff had the greatest temporal effect on the fish communities in secondary channels and appeared to reset the communities by displacing those species that were less resistant to increased current velocities. This annual event may help maintain native fish species adapted to these conditions in the San Juan River while moderating the abundance of nonnative fish species.     

Fish community structure and environmental correlates in the highly altered southern Sacramento-San Joaquin Delta

We sampled 11 sites in the southern Sacramento-San Joaquin Delta from 1992–1999, to characterize fish communities and their associations with environmental variables. Riparian habitats were dominated by rock-reinforced levees, and large water diversion facilities greatly influenced local hydrodynamics and water quality. We captured 33 different taxa, only eight of which were native. None of the native species represented more than 0.5% of the total number of individuals collected. The abundance of native species was consistently low but typically peaked during high outflow periods. Fish communities were predominantly structured along environmental gradients of water temperature and river flow. Native species (tule perch, Hysterocarpus traski, & Sacramento sucker, Catostomus occidentalis) were associated with conditions of high river flow and turbidity, while the majority of the non-native species were associated with either warm water temperature or low river flow conditions. The exceptions were the non-native striped bass, Morone saxatilis, and white catfish, Ameiurus catus, which were positively associated with relatively high river flow. Variation in fish community structure was greater among river locations within years than within river locations among years, thus fish communities at each river location were consistently different each year. Differences in fish communities among river locations were correlated with river flow and turbidity. We predict that the fish communities of this region will remain numerically dominated by non-native species if the environmental conditions we observed persist in the future.     

Competition for food between an introduced crayfish and two fishes endemic to the Colorado River basin

Synopsis Crayfish are not native to the Colorado River basin (CRB), however they are now established in portions of the mainstem and in many tributaries. I used density manipulation experiments in a laboratory setting to determine intra- and interspecific competition for food between Orconectes virilis, an aggressive polytrophic crayfish now common in the CRB, and two native fishes: Gila chub, Gila intermedia, and flannelmouth sucker, Catostomus latipinnis. I tested each fish species in separate trials. Growth of Gila chub decreased when animal densities increased, however they were more affected by intraspecific competition than by crayfish presence. In contrast, growth of flannelmouth suckers was more affected by crayfish than by intraspecific competition. Crayfish growth was not significantly altered by presence of either fish. Crayfish thus reduced fish growth by competition for food, but the effect differed markedly between the two species. An erratum to this article can be found at .     

Lake acidity,fish predation,and the distribution and abundance of some littoral insects

Densities of Corixidae (Hemiptera), larval Odonata, and large larval Trichoptera were estimated in the littoral zone of small lakes in an acid-stressed area near Sudbury, Ontario. Fish were present in some lakes and absent in others, and fishless lakes occurred across a wide range of pH. Corixidae were significantly more abundant in lakes without fish than in lakes with fish, and their numbers were not related to the pH of fishless lakes. Anisoptera (Odonata) larvae tended to be more numerous in benthic samples from fishless lakes than from lakes with fish, and their exuviae were significantly more abundant around fishless lakes. In most lakes, the assemblage was dominated by three species; Leucorrhinia glacialis, Libellula julia, and Cordulia shurtleffi. In lakes containing white sucker, Catostomus commersoni, Gomphus spp. were most numerous. In the most acid fishless lakes, L. julia was uncommon, and L. glacialis was extremely abundant. In fishless lakes, numbers of Anisoptera larvae and exuviae were negatively correlated with pH, though species richness was positively correlated with pH. Exuviae of Zygoptera (Odonata) were more abundant around fishless lakes, irrespective of pH. Larvae of Limnephilus (Trichoptera) were most abundant in non-acid fishless lakes, and absent at pH<5.2. Abundances of Banksiola (Trichoptera) were negatively correlated with the pH of fishless lakes.     

Microsatellite markers for the endangered razorback sucker, Xyrauchen texanus, are widely applicable to genetic studies of other catostomine fishes

We developed 10 polymorphic microsatellite markers for the federally endangered razorback sucker, Xyrauchen texanus. PCR optimization and cross-species amplification experiments indicated that these markers will be useful for analysis of fine-scale population structure in razorback and two other sucker species; the white sucker, Catostomus commersonii and the Rio Grande sucker, C. plebeius. Alleles at locus Xte4 did not overlap when compared between razorback and bluehead (C. discobolus) suckers and permits detection of F1 hybrids. These microsatellite markers appear widely applicable for identifying genetic consequences of population decline, hatchery rearing and release, and hybridization in razorback and other castostomine suckers.