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The blue sucker (Cycleptus elongatus) is a widespread North American catostomid fish that appears to be declining throughout much of its range. Here, we describe the isolation and characterization of eleven microsatellite loci developed for population genetic studies in the genus. We show that an additional step of cloning and sequencing can be useful in isolating paralogous loci that often co-amplify in polyploid organisms. Finally, we present results of cross-species amplifications tests in nine other taxa, including four catostomids. [ABSTRACT FROM AUTHOR]

The genetic variation, phylogeny and biogeography of catostomid fishes were investigated based on mitochondrial cytochrome b and nuclear 18S-ITS1-5.8S DNA sequences. The pair-wise genetic distance of cytochrome b for 17 catostomids varied considerably, from 1·00% ( Chasmistes brevirostris and Deltistes luxatus) to 23·3% ( Cycleptus elongatus and Moxostoma anisurum). The size of the 18S-ITS1-5.8S sequence ranged from 315 bp ( Moxostoma robustum) to 575 bp ( Ictiobus cyprinellus). The 18S-5.8S region was conservative and the length of ITS1 regions was found to vary considerably among the seven catostomids. It is interesting that the primitive I. cyprinellus and Myxocyprinus asiaticus had longer ITS1 regions than suckers from the Catostominae. Based on the nucleotide substitution model, the nuclear 18S-5.8S gene had a faster evolution rate than the mitochondrial cytochrome b gene. In a phylogenetic analysis, 17 catostomids from 14 genera representing three subfamilies were not distinctly divergent. Nevertheless, three major genetically divergent clades were identified. Clade I (95% bootstrap) included general Catostomus, Thoburnia, Xyrauchen, Chasmistes and Deltistes. Clade II (94% bootstrap) included Hypentelium, Moxostoma and Scartomyzon. Clade III (77% bootstrap) was a monophyletic Ictiobinae containing I. cyprinellus and Carpiodes carpio. The biogeography of old world catostomids followed a disperse event, and the speciation of the extant catostomids was a vicariance event. The earliest catostomid evolved in Asia from one branch of ostariophysans in the early Tertiary. Before the Eocene, catostomids belonging to the genus Amyzon had a wide, trans-Pacific distribution over Asia and North America. Later, oceanic ingression and the Tertiary glacial event forced catostomids to evolve on both mainlands, respectively. The present disjunct distribution pattern of catostomids was presumably due to competitive pressure from cyprinids, geographical events, their Late Cenozoic radiation in North America and glacial events. The divergence time based on the mitochondrial and nuclear DNA sequences suggests that catostomids began to diverge in the early or mid-Miocene, which agrees with the fossil evidence. [ABSTRACT FROM AUTHOR]

Abstract: Savanna plant species are capable of regenerating both sexually and asexually. The importance of each regeneration mechanism depends on the species, the type and the intensity of disturbance. This paper describes the relative importance of sexual and asexual regeneration for the restoration of a selectively cut savanna woodland in Burkina Faso. Plantlets regenerated sexually or asexually were determined by excavating the below ground system and assessing basal and aerial sprouts within 144 quadrats along transects in 2, 5, 10 year-cut and control plots. The result shows that seedling sprouts were predominant (83%) compared to root sucker (4%), coppice (5%), water sprout (2%) and layering (less than 1%). True seedlings constituted a minor component (5%) of the plantlet population. A total of 54 woody species was found in the plantlet population with 52 presenting seedling sprouts. Twelve species were found regenerating from both seeds and root buds; of which Dichrostachys cinerea, Pteleopsis suberosa and Detarium microcarpum had the highest number of plantlets. Feretia apodanthera was the only layering species encountered in the sampled area. Coppices, root suckers and water sprouts showed higher height and bigger collar diameter compared to seedling sprouts and true seedlings. It can be concluded that sexual reproduction is the dominant mechanism of seedling recruitment in this disturbed savanna-woodland, and that its success relies on the ability of plantlets of seed origin to resprout abundantly. [Copyright &y& Elsevier]

The present study concerned the morphology and surface ultrastructure of a plagiorchid, Glossidium pedatum, from bagrid fish of the river Nile in Egypt . Adult G. pedatum have an elongate body, tapered towards the anterior and posterior ends. Their oral sucker is small, sub-terminal and rounded, measuring 0.200 mm in diameter. Sensory papillae around the oral sucker usually occur in small clusters of three to eight each. The ventral sucker is large, situated at the anterior end of the second third of the body, 0.299 mm in diameter, and is surrounded by three pairs of sensory papillae. Both suckers have rounded rims covered by tegumental spines. On the anterior part of the ventral surface of the body tegumental spines are small, pointed and closely spaced. A small triangular area of tegument anterior to the ventral sucker is devoid of spines. Tegumental spines on the mid-region of the body slightly increase in size and number, especially towards the lateral aspects and posterior to the ventral sucker. Towards the posterior end of the body the spines progressively decrease in both size and number. The dorsal side exhibits similar surface features but the spines are less numerous and slightly smaller. [ABSTRACT FROM AUTHOR]

Spawning aggregations of five species of catostomids were observed on the two mid-channel gravel bars of the Savannah River, Georgia and South Carolina, in 2004 and 2005 to assess the degree of spatial and temporal overlap in the use of this habitat and determine the habitat preferences leading to segregation. Spawning catostomids showed a considerable amount of temporal overlap in their use of these mid-channel gravel bars. The observed temporal overlap was consistent between 2004 and 2005 and corresponded to temperatures at which species were present. The distribution of catostomids was not uniform at the upstream gravel bar. Carpsuckers Carpiodes sp., spotted sucker Minytrema melanops and robust redhorse Moxostoma robustum both demonstrated some spatial overlap with notchlip redhorse Moxostoma collapsum; however, their overall distributions were different from one another. Northern hogsucker Hypentelium nigricans was present across the gravel bars, apparently as an egg predator. Spawning catostomids segregated based on flow, depth, slope and substratum size. Whether due to limited habitat availability or changes in the timing of reproduction due to altered cues, temporal and spatial overlap occurs between spawning catostomids despite the apparent partitioning of available spawning habitat. It is unclear, however, if this overlap results in excessive mortality in the early life-history stages of these species. Results suggest spatial overlap among catostomid species was minimized due to species spawning in areas within a narrow range of conditions. Intraspecific interactions such as nest site superimposition or disturbance may be a concern. [ABSTRACT FROM AUTHOR]

We collected and analyzed 2,707 large fish from 626 stream/river sites in 12 western U.S. states using a probability design to assess the regional distribution of whole fish mercury (Hg) concentrations. Large (>120 mm total length) fish Hg levels were strongly related to both fish length and trophic guild. All large fish that we sampled exceeded the wet weight detection limit of 0.0024 μg·g-1, and the mean Hg concentration in piscivores (0.260 μg·g-1) was nearly three times that of nonpiscivores (0.090 μg·g-1). Fish tissue Hg levels were not related to local site disturbance class. After partialing out the effects of fish length, correlations between Hg and environmental variables were low (r < 0.3) for the most common genera (trout and suckers). Stronger partial correlations with Hg (r > 0.5) were observed in other genera for pH, stream size, and human population density but patterns were not consistent across genera. Salmonids, the most common family, were observed in an estimated 125,000 km of stream length, exceeded 0.1 μg Hg·g-1 (deemed protective for fish-eating mammals) in 11% of the assessed stream length, and exceeded the filet equivalent of 0.3 μg Hg·g-1 (USEPA tissue-based water quality criterion) in 2.3% of that length. Piscivores were less widespread (31,400 km), but they exceeded the 0.1 and 0.3 μg Hg·g-1 criteria in 93% and 57% of their assessed stream length, respectively. Our findings suggest that atmospheric transport is a key factor relative to Hg in fish across the western United States. [ABSTRACT FROM AUTHOR]

We visually censused Warner sucker cohorts in a low gradient stream reach and determined microhabitat use from random availability data. For above-water visual censuses (AVC), we counted aggregations while slowly wading through Honey Creek three times both years. Underwater visual censuses (UVC) were done in 1993 by snorkeling. Mean focal point velocity (FPV) during AVC significantly differed by year but not by census date, and mean depth did not differ for either. In 1993 we found suckers used microhabitats with FPV between >3 to 6 cm/s (X1² = 3.93, P < 0.05) and depth between >20 to 40 cm (X1² = 4.5, P < 0.05). Suckers avoided areas where FPV exceeded 15 cm/s (Xl² = 18.7, P < 0.001) and depth between >60 to 80 cm (X1² = 8.1, P < 0.005). Aggregate abundance was significantly related to both distance to (r64 = -0.45, P = 0.0002) and percentage (r64 = 0.44, P = 0.0003) submerged vegetation. We found 97% of suckers (N/m³) in riffle/run habitat during UVC. When mean flow was used as a continuous variable, we found suckers occupied habitats >3 cm³/s and avoided habitats >2 cm³/s in a disproportionate manner relative to availability. These results suggest young suckers select vegetated areas with moderate flow and relatively shallow depths during first few months of life. This information improves our understanding of ecological habits of early life stages of a rare western catostomid during stream residence, which could be useful for conservation management in low gradient stream reaches of Warner Basin. [ABSTRACT FROM AUTHOR]

A new fossil Ictiobus species is described, based on an abundant collection of well-preserved isolated bones found in lacustrine deposits of Pliocene (Blancan) age near Tula de Allende, state of Hidalgo, central Mexico. This fossil Ictiobus species shows the diagnostic character of the genus. In the palatine bone the ethmoid process is longer than the premaxillary process. Suspensorial pleural ribs with trapezoidal shape and a dentary bone with extremely short and wide gnathic ramus are the characters that support the creation of this new Ictiobus species. The fossil record of Ictiobus, the first known in Mexico, extends the paleogeographical distribution known of this genus, which had been previously restricted to the USA. [ABSTRACT FROM AUTHOR]

Research on populations from radioactively contaminated areas around Chornobyl has produced ambiguous results for the presence of radiation effects. More studies are needed to provide information on whether radiation exposure at Chornobyl significantly affected genetic diversity in natural populations of various taxa. Eleven and nine variable microsatellite loci were used to test for differences in genetic diversity between reference and Chornobyl populations of two cattail species ( Typha angustifolia and Typha latifolia, respectively) from Ukraine. Our purpose was to determine whether radiation had a significant impact on genetic diversities of the Chornobyl Typha populations, or if their genetic composition might be better explained by species demography and/or changes in population dynamics, mainly in sexual and asexual reproduction. Populations closest to the reactor had increased genetic diversities and high number of genets, which likely were due to factors other than radiation including increased gene flow among Chornobyl populations, enhanced sexual reproduction within populations, and/or origin of the genets from seed bank. Both Typha species also demonstrated small but significant effects associated with latitude, geographical regions, and watersheds. Typha's demography in Ukraine possibly varies with these three factors, and the small difference between Chornobyl and reference populations of T. latifolia detected after partitioning the total genetic variance between them is probably due primarily to these factors. However, the positive correlations of several genetic characteristics with radionuclide concentrations suggest that radiation may have also affected genetics of Chornobyl Typha populations but much less than was expected considering massive contamination of the Chornobyl area. [ABSTRACT FROM AUTHOR]

Abstract: In the absence of chemical vegetative management tools, young regenerating trembling aspen (Populus tremuloides) is typically removed mechanically from sites intended for white spruce (Picea glauca) regeneration. In many cases the aspen vigorously re-suckers and re-sprouts after cutting all the stems. A field study was established to test whether the regeneration of aspen can be reduced by maintaining residual saplings and/or by the timing of cleaning. It was further tested how these treatments affect root carbohydrate reserves. Nine healthy, 10-year-old aspen stands were manually cleaned to three residual aspen densities (0, 500, and 1500 stems per hectare) at three times of the year (late summer, winter, and spring). Retaining residual aspen reduced regeneration by 23–39% relative to complete removal; however, the amount of regeneration was not affected by season. Height growth and leaf area was reduced in spring cleanings compared to late summer and winter and in both residual trees treatments compared to the complete removal. The vast majority of regeneration was from stump sprouting. Generally, as the residual density increased, regeneration decreased; however, regeneration after the first growing season was still too abundant for these treatments to be a viable option for density management of aspen. Maintaining residual stems reduced the root carbohydrate reserves in root associated with regeneration compared to reserves in roots associated with residual saplings or in the control plot. Only in the complete removal treatment did root reserves recover to control levels within one growing season. [Copyright &y& Elsevier]

The cestode Nomimoscolex sudobim Woodland, 1935 (Proteocephalidea) is redescribed on the basis of its type-specimens and recently collected material found in the intestine of the ‘sudobim’ Pseudoplatystoma fasciatum (Siluriformes: Pimelodidae) (type-host), from the Amazon River (near the type-locality). Nomimoscolex pertierrae n. sp. is described from the ‘surubi’ Pseudoplatystoma corruscans from the Paraná River around Porto Rico. Among fifteen known Nomimoscolex species, only N. sudobim possess a cortical uterus in combination with osmoregulatory canals some distance internal to the proglottis margins, as in N. pertierrae n. sp. N. pertierrae differs from N. sudobim, which exhibits the most similarity with the former species, in the morphology of the scolex, the size and unusual shape of microtriches (slender digitiform) on the internal and marginal regions of the suckers, and in the lower mean number of testes [(114 in N.␣pertierrae, ranging between 216 (recently collected material) and 240 (type-material) in N. sudobim)]. The material described as N. sudobim by Pavanelli & Rego (1992) from the intestine of P. corruscans is considered to be N. pertierrae. The utility of microtriches as characters for distinguishing between species is demonstrated in the clear differences in the shape of those of N. pertierrae and N. sudobim. The morphology of microtriches warrants more attention in future studies on the taxonomy of proteocephalidean cestodes. [ABSTRACT FROM AUTHOR]

The evolutionary potential of a species is determined by its genetic diversity. Thus, management plans should integrate genetic concerns into active conservation efforts. The copper redhorse ( Moxostoma hubbsi) is an endangered species, with an endemic distribution limited to the Richelieu River and a short section of the St Lawrence River in Quebec, Canada. The population, gradually fragmented since 1849, is characterized by a decline in population size and a lack of recruitment. A total of 269 samples were collected between 1984 and 2004 and genotyped using 22 microsatellite loci, which indicated that these fish comprise a single population, with a global FST value of only 0.0038. Despite a small census size (∼500), a high degree of genetic diversity was observed compared to common values for freshwater fishes (average number of 12.5 alleles/locus and average HO of 0.77 ± 0.08). No difference was observed between expected and observed pairwise values of relatedness (rxy: −0.00013 ± 0.11737), suggesting an outbred population. Long-term N e was estimated at 4476 whereas contemporary N e values ranged from 107 to 568, suggesting a pronounced yet gradual demographic decline of the population, as no bottleneck could be detected for the recent past. By means of simulations, we estimated N e would need to remain at more than ∼400 to retain 90% of the genetic diversity over 100 years. Overall, these observations corroborate other recent empirical studies confirming that long generation times may act as a buffering effect contributing to a reduction in the pace of genetic diversity erosion in threatened species. [ABSTRACT FROM AUTHOR]

We recorded the movement of Sacramento suckers, Catostomus occidentalis, and hitch, Lavinia exilicauda, before and during a controlled flood release on a regulated California Central Valley River, using radio telemetry. Both species made small, local movements (<550 m) during pre-flood flows. During flood releases, some individual suckers made significantly larger movements (>8100 m) both up and downstream of pre-flood flow locations within the main channel while others did not. In contrast, increased flows did not significantly influence hitch movement from a side-channel pool. Sacramento suckers tended to move upstream during flow increases and downstream during flow reductions while no strong relationship for hitch was apparent. These data show that native Central Valley fishes may exhibit a variety of responses to flow change, including schooling and spawning activity, movements to refugia from higher velocities and no marked change. Managers must take into account life history, age and timing associated with specific species when implementing controlled flow strategies. [ABSTRACT FROM AUTHOR]

The Lost River sucker ( Deltistes luxatus) is a federally listed, endangered species inhabiting the hypereutrophic waters of Upper Klamath Lake in southern Oregon, USA. High pH (≥10) and elevated ammonia concentrations (≥1 mg NH3-N/L) often occur during blooms of cyanobacteria ( Aphanizomenon flos-aquae) in the lake, with major fish kills sometimes following a mid- or late-summer “crash” of the cyanobacterial population. Previous histopathology analyses and bacterial sampling indicated that infections of the pathogenic bacterium Flavobacterium columnare might contribute to the fish kills. We hypothesized that prior exposure to adverse water quality conditions increases the susceptibility of Lost River suckers to F. columnare infections. To test this, we exposed juvenile Lost River suckers to four sublethal ammonia concentrations at pH 9.4 for 62 d. On day 31, fish in half of the aquaria were exposed to F. columnare. As expected, survival of the Lost River suckers decreased in aquaria inoculated with F. columnare. Ninety-four percent of the fish that died were infected by F. columnare in the gills, kidney, or skin, whereas none of the survivors or unexposed control fish was infected. However, contrary to our hypothesis, survival of the fish exposed to F. columnare increased significantly ( p < 0.05) as unionized ammonia concentrations increased. Our results suggest that complex interactions can complicate prediction of the responses of fish to concurrent chemical stressors and bacterial pathogens. [ABSTRACT FROM AUTHOR]

In most wadeable streams of the mid-Atlantic Highlands region of the eastern USA, physical habitat alteration is the primary stressor for fish. Models that predict the occurrence of stream-fish species based on habitat measures can be useful in management, and predicted probability of occurrence can be a measure of habitat suitability with which to compare alternative habitat management scenarios and assess the effectiveness of stream restoration. We developed such models for each of 13 mid-Atlantic Highlands stream-fish species and species groups by using multiple logistic regression and six instream habitat measures: depth, temperature, substrate, percent riffles, cover, and riparian vegetation. The predictive ability of the models ranged from 61% to 79% in cross-validation and from 38% to 85% on an independent data set. The models predicted well for both the original and test data sets for black bass Micropterus spp., brook trout Salvelinus fontinalis, darters Etheostoma and Percina spp., shiners Notropis spp., and suckers Hypentelium and Moxostoma spp. Suitable habitat for most of the fish species groups was characterized by intermediate depth, a high percentage of cobble and riparian vegetation, and a low percentage of instream cover. The relatively high predictive ability and reasonable responses to habitat measures indicated that these models could be useful for management. However, the models were more sensitive to depth and temperature than to measures that are more commonly affected by restoration activities, such as cover and riparian vegetation. [ABSTRACT FROM AUTHOR]

Abstract: Reports of decreasing quaking aspen (Populus tremuloides) cover in forests of the western USA have caused concern about the long-term persistence of aspen on landscape scales. We assessed changes in overstory aspen dominance on the Uncompahgre Plateau in western Colorado over a 20 year period. We measured stand density, species composition and regeneration in 53 undisturbed, mature pure aspen, pure conifer, and mixed aspen/conifer stands originally inventoried between 1979 and 1983. Ages of overstory and understory trees were used to evaluate long-term change in regeneration and overstory development. While pure aspen stands occupy 16% of the study area, mixed aspen and conifer stands cover 62% of the forested landscape on the Uncompahgre Plateau. Pure aspen stands were self-thinning, but stable over the twenty-year study period, with high amounts of regeneration and without conifer invasion. Mixed stands of aspen and conifer had undergone significant change. In aspen dominated mixed species stands, conifer basal area increased from 10 to 23m2 ha−1 in the last 20 years, while aspen basal area decreased. In conifer dominated mixed species stands, conifer basal area increased from 18 to 24m2 ha−1. Most overstory aspen in pure aspen stands were between 80 and 120 years old. Substantial aspen suckering was occurring, but all suckers were &#60;20 years old, indicating lack of current growth into the overstory. Aspen suckering was occurring in mixed species stands, but again, most suckers were &#60;20 years old, and few overstory trees were &#60;100 years old. In contrast, understory and overstory conifers spanned ages from &#60;20 to over 250 years old. Aspen dominance is decreasing in the forested communities of the study area. Pure stands are likely to persist without decline for a considerable time. Mixed stands are likely to continue to experience a decrease in overstory aspen canopy dominance. These changes are probably within the historic range of variability, but restoration of aspen canopy cover consistent with an early- to mid-seral landscape condition would require disturbances such as fire or cutting to create canopy gaps to permit growth of suckers into the overstory of mixed species stands. [Copyright &y& Elsevier]

The productivity of hybrid aspen stands in southern Sweden, originating from clone selections performed during the 1980s, was investigated. Thirteen former research and demonstration sites were included. Repeated measurements of tree diameters and heights were taken, from which yields were estimated. The results indicate that the mean annual increment, obtained without any artificial addition of fertilizers or irrigation, will exceed 20 m3 of stem wood ha−1 a−1 during a 20–25-year rotation period. This corresponds to a total average woody biomass production, including branches, of over 8 tonnes dry matter ha−1 a−1. These production levels show that hybrid aspen is a competitive alternative for short rotation forestry in Sweden, and that the clone selection programme has greatly enhanced productivity, compared with published growth rates of the material previously used. For comparison, two stands that regenerated via root suckers from material used in the breeding programme up to the 1960s were included. They showed higher growth than the 13 planted stands, mainly due to higher stem density and faster height development. This indicates that even further increases in hybrid aspen yield are possible in stands derived from suckers of the most recently selected clones. Thinning studies, including three different weights of thinning, were carried out on five of the sites. Five years after the start of the treatments, stands given no thinning showed significantly higher current annual increment, but significantly smaller mean stem diameter than stands in which thinning was applied. However, the faster diameter development (and thus higher volumes of valuable wood assortments) associated with heavier thinnings may compensate economically under current market conditions for the loss in total volume production. [ABSTRACT FROM AUTHOR]

Abstract: The surface of the tegument of the scolex and the immature proglottides of Monticellia belavistensis, M. ventrei, Nomimoscolex chubbi, and N. lopesi is described using scanning electron microscopy. Only blade-like spiniform microtriches and filiform microtriches were observed in the species studied. The types, size and density of microtriches on the apical region surface of the scolex, central cavity surface of suckers, marginal ring surface of suckers, non-adherent surface of suckers, proliferation zone surface, and immature proglottis surface were compared among these species. The distribution pattern of the microtriches was not a reliable feature to discriminate among the genera considered in this study. It varied in each of the species of Monticellia examined, and did not permit to split the heterogeneous genus Nomimoscolex. However, the microthrix pattern can be regarded as an additional diagnostic feature to distinguish among species of proteocephalideans. Further comparative research involving other species of proteocephalid taxa is needed to elucidate the systematic value of the tegumental morphology. [Copyright &y& Elsevier]

This article presents information related to ecology. Rhizomatous multi-stemmed erect deciduous shrub, strongly suckering, mature clones forming impenetrable thickets. Rhizomes (R.)woody, with orange-brown cortex and triangulate scale leaves. Rhizome branches and suckers emerge from axillary buds subtended by scale leaves. No subspecies of rosa rugosa have been recognized in the British Isles. Despite the many cultivated varieties of the species, mainly forms close to the wild type are seen naturalized.

The decline of aspen (Populus tremuloides) in the western United States is well known but the role that pocket gophers (Thomomys spp.) may play in that decline is not known. We investigated the effects of pocket gophers on aspen regeneration in Utah through a series of 4 treatments comprised of baited and fenced plots. The treatments were control (no treatment), baited (pocket gopher removal), fenced (ungulate exclusion), and fenced and baited combined. Fencing reduced browsing rates and increased the height and growth of aspen suckers but did not affect their density. Pocket gopher removal had no effect. Aspen suckers on control plots were the only ones that showed no increase in growth between spring and fall. Overall, these results indicate that the effect of pocket gophers on aspen regeneration is minimal compared to the effects of browsing by ungulates and livestock. [ABSTRACT FROM AUTHOR]

We investigated the potential of prepositioned grid electrofishers as a means of collecting broodstock for the rare robust redhorse Moxostoma robustum. We found that combined with visual observation, this technique allowed for the efficient capture of fish in breeding condition. We were able to harvest eggs in the field and bring only fertilized eggs into the hatchery. There was no need to induce spawning hormonally. Although their use is limited by water depth and clarity, prepositioned grid electrofishers used in conjunction with visual observation warrants further consideration as an effective tool for the collection of reproductively active broodstock for conservation purposes. [ABSTRACT FROM AUTHOR]

Abstract Two new species of hemiurine hemiurid are described from Spratelloides robustus off Woodman Point in southern Western Australia. Hemiurus lignator n. sp. differs from its congeners by a combination of similar-sized suckers, long sinus-sac, tandem testes, relatively elongate shape and unthickened seminal vesicle wall. Parahemiurus xylokopos n. sp. differs from its congeners in a combination of its squat form, its distinctly lobed vitellarium and the proximity of the gonads to the ventral sucker. P. merus (Linton, 1910) is reported from Acanthopagrus australis,Pomatomus saltatrix and Trachinotus coppingeri off northern New South Wales, Caranx sexfasciatus, Scorpis lineolata, Siganus nebulosus, Thunnus tonggol and T. coppingeri off southern Queensland, Cephalopholis boenak and Euthynnus affinis off Heron Island, southern Great Barrier Reef, P. saltatrix off southern Western Australia and Priacanthus hamrur off New Caledonia. [ABSTRACT FROM AUTHOR]

Catostomid fishes are a diverse family of 76+ freshwater species that are distributed across North America in many different habitats. This group of fish is facing a variety of impacts and conservation issues that are somewhat unique relative to more economically valuable and heavily managed fish species. Here, we present a brief series of case studies to highlight the threats such as migration barriers, flow regulation, environmental contamination, habitat degradation, exploitation and impacts from introduced (non-native) species that are facing catostomids in different regions. Collectively, the case studies reveal that individual species usually are not threatened by a single, isolated factor. Instead, species in general face numerous stressors that threaten multiple stages of their life history. Several factors have retarded sucker conservation including widespread inabilities of field workers to distinguish some species, lack of basic natural history and ecological knowledge of life history, and the misconception that suckers are tolerant of degraded conditions and are of little social or ecological value. Without a specific constituent group lobbying for conservation of non-game fishes, all such species, including members of the catostomid family, will continue to face serious risks because of neglect, ignorance, and misunderstanding. We suggest that conservation strategies should incorporate research and education/outreach components. Other conservation strategies that would be effective for protecting suckers include freshwater protected areas for critical habitat, restoration of degraded habitat, and design of catostomid-friendly fish bypass facilities. We believe that the plight of the catostomids is representative of the threats facing many other non-game freshwater fishes with diverse life-history strategies globally. [Copyright &y& Elsevier]

Toxicity tests using standard effluent test procedures described by the U.S. Environmental Protection Agency were conducted withCeriodaphnia dubia, fathead minnows (Pimephales promelas), and seven threatened and endangered (listed) fish species from four families: (1) Acipenseridae: shortnose sturgeon (Acipenser brevirostrum); (2) Catostomidae; razorback sucker (Xyrauchen texanus); (3) Cyprinidae: bonytail chub (Gila elegans), Cape Fear shiner (Notropis mekistocholas) Colorado pikeminnow (Ptychocheilus lucius), and spotfin chub (Cyprinella monacha); and (4) Poecillidae: Gila topminnow (Poeciliopsis occidentalis). We conducted 7-day survival and growth studies with embryo-larval fathead minnows and analogous exposures using the listed species. Survival and reproduction were also determined withC. dubia. Tests were conducted with carbaryl, ammonia-or a simulated effluent complex mixture of carbaryl, copper, 4-nonylphenol, pentachlorophenol and permethrin at equitoxic proportions. In addition, Cape Fear shiners and spotfin chub were tested using diazinon, copper, and chlorine. Toxicity tests were also conducted with field-collected effluents from domestic or industrial facilities. Bonytail chub and razorback suckers were tested with effluents collected in Arizona whereas effluent samples collected from North Carolina were tested with Cape Fear shiner, spotfin chub, and shortnose sturgeon. The fathead minnow 7-day effluent test was often a reliable estimator of toxic effects to the listed fishes. However, in 21 % of the tests, a listed species was more sensitive than fathead minnows. More sensitive species results varied by test so that usually no species was always more or less sensitive than fathead minnows. Only the Gila topminnow was consistently less sensitive than the fathead minnow. Listed fish species were protected 96% of the time when results for both fathead minnows andC. dubiawere considered, thus reinforcing the value of standard whole-effluent toxicity tests using those two species. If the responses of specific listed species are important for management decisions, our study supports the value in developing culture and testing procedures for those species. [ABSTRACT FROM AUTHOR]

A study of the fish faunas in all or parts of seven Illinois river basins revealed an average loss of 8.4 species per basin over approximately the last 100 y. In contrast, between the 1980s and 1990s, five basins showed an increase in the species richness (number of species) and two showed a statistically significant increase (paired t-test) in the species richness per sample site. Only the Kaskaskia River basin had a significant decline (paired t-test) in the species richness per sample site between the 1980s and 1990s. Minnows (Cyprinidae) had the largest number of species showing declines over the last 100 y and was followed in decreasing order by darters and perches (Percidae), catfishes (Ictaluridae), suckers (Catostomidae), topminnows (Fundulidae) and sunfishes (Centrarchidae). Changes in the overall fauna since the 1980s show an increase in species occurrence, but minnows and catfishes showed little net change and suckers, sunfishes and darters showed a positive increase in occurrence. [ABSTRACT FROM AUTHOR]

The Native Fishes Work Group, formed in 1991, developed and implemented a protocol to enhance the dwindling razorback sucker population in Lake Mohave, Arizona-Nevada. This large, genetically diverse population is severely reduced in size as a result of recruitment failure associated with predation on larvae. To circumvent this problem, wild larvae are captured, reared in protective custody until they are large enough to escape predation, and then released back into the lake. We present results of a monitoring program designed to assess the effectiveness of the sampling design in transmitting the high genetic diversity found in wild adults. Variation in a fragment from the mitochondrial DNA gene cytochromebwas examined by analysis of single-stranded polymorphisms and direct sequencing. Samples were characterized from three life history stages. Characterization of wild adults verified previous results that identified considerable diversity and provided baseline data. Samples of larvae from several temporal collections from throughout the spawning season and four geographical areas were characterized for 7 years (1997–2003) to assess the transmission of genetic variation from wild adults to larvae. Several analyses identified significant differences among temporal collections, resulting from sampling errors associated with finite number of females spawning at a given time and place. Comparisons among areas and years failed to identify significant variation, indicating that pooled collections for each year possess the same levels and patterns of genetic variation. Examination of repatriates representing 11 years (1992–2002) also failed to identify significant differences among cohorts; however, some sample sizes were small and theamovamay lack sufficient power to detect differences. Contrasts of wild adults, larvae, and repatriates identified statistically significant differences among collections within these three groups; however, levels of variation are small and not biologically meaningful. More importantly, this analysis failed to detect significant differences among adults, larvae, and repatriates indicating that the program has been achieving its goal of transmitting variation from adults through the larvae and into the repatriate population. The reproductive capability of repatriates has not been examined, so it is unknown if the program will maintain genetic variation found in the original adult population. This will be most easily achieved by periodic monitoring of genetic variation in larval samples. If levels of variation become reduced in repatriates, levels and patterns of diversity in larvae are also expected to become reduced, and deviations in estimates of genetic diversity may become larger and more frequent. If this is the case, intervention may be necessary to ensure that certain individuals are not over-represented in the repatriate population. [ABSTRACT FROM AUTHOR]

The variability in size structure and relative abundance(CPUE; number of fish≥200 mm total length,LT, collected per hour of electrofishing or trammel netting) of three native Colorado River fishes, the endangered humpback chubGila cypha, flannelmouth suckerCatostomus latipinnusand bluehead suckerCatostomus discobolus, collected from electrofishing and trammel nets was assessed to determine which gear was most appropriate to detect trends in relative abundance of adult fishes. Coefficient of variation(CV) of CPUE ranged from 210 to 566 for electrofishing and 128 to 575 for trammel netting, depending on season, diel period and species. Mean CV was lowest for trammel nets for humpback chub( P = 0·004) and tended to be lower for flannelmouth sucker( P = 0·12), regardless of season or diel period. Only one bluehead sucker>200 mm was collected with electrofishing. Electrofishing and trammel netting CPUE were not related for humpback chub( r = −0·32,P = 0·43) or flannelmouth sucker( r = −0·27,P = 0·46) in samples from the same date, location and hour set. Electrofishing collected a higher proportion of smaller(<200 mmLT) humpback chub( P < 0·001), flannelmouth suckers( P < 0·001) and bluehead suckers( P < 0·001) than trammel netting, suggesting that conclusions derived from one gear may not be the same as from the other gear. This is probably because these gears fished different habitats, which are occupied by different fish life stages. To detect a 25% change in CPUE at a power of 0·9, at least 473 trammel net sets or 1918 electrofishing samples would be needed in this 8 km reach. This unattainable amount of samples for both trammel netting and electrofishing indicates that detecting annual changes in CPUE may not be practical and analysis of long-term data or stock assessment models using mark-recapture methods may be needed to assess trends in abundance of Colorado River native fishes, and probably other rare fishes as well. [ABSTRACT FROM AUTHOR]

Catostomidae represent an important family of freshwater fishes mainly distributed in North America, but also found in Eurasia. This paper describes the development of microsatellite DNA markers for a highly threatened member of this family, the Copper redhorse ( Moxostoma hubbsi), as well as cross-catostomids amplifications. 168 tetra-nucleotide loci were screened to develop 21 polymorphic markers, with an average number of 8.5 alleles per locus and observed heterozygosity ranging between 0.52 and 1.00. Successful amplification was obtained for 12 other members of the family at between seven to 19 loci, with between two to 18 loci being polymorphic per species. [ABSTRACT FROM AUTHOR]

The primary objective of the present study was to test whether agricultural chemical runoff was associated with in-stream genotoxicity in native fish. Using Sacramento sucker (Catostomus occidentalis), we combined field-caging experiments in an agriculturally dominated watershed with controlled laboratory exposures to field-collected water samples, and we coupled genotoxicity biomarker measurements in fish with bacterial mutagenicity analysis of water samples. We selected DNA strand breakage as a genotoxicity biomarker and Ames Salmonella mutagenicity tests as a second, supporting indicator of genotoxicity. Data from experiments conducted during rainfall runoff events following winter application of pesticides in 2000 and 2001 indicated that DNA strand breaks were significantly elevated in fish exposed to San Joaquin River (CA, USA) water (38.8, 28.4, and 53.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively) compared with a nearby reference site (15.4, 8.7, and 12.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively). Time-course measurements in field experiments supported a linkage between induction of DNA strand breakage and the timing of agricultural runoff. San Joaquin River water also caused significant reversion mutation in two Ames Salmonella tester strains. Salmonella mutagenicity corroborated in-stream effects, further strengthening a causal relationship between runoff events and genotoxicity. Potentially responsible agents are discussed in the context of timing of runoff events in the field, concordance between laboratory and field exposures, pesticide application patterns in the drainage, and analytical chemistry data. [ABSTRACT FROM AUTHOR]

We examined near-shore habitat use by larval shortnose and Lost River suckers in the lower Williamson River and Upper Klamath Lake of south-central Oregon. Emergent macrophytes Scirpus, Sparganium and Polygonum supported significantly more, larger, and better-fed larvae than submergent macrophytes, woody vegetation, or open water. Abundance, size, and gut fullness were similar for sucker larvae collected from different emergent macropytes. During the larval period, there was no evidence of density dependant effects or habitat shifts. Ranked catch per unit effort data indicated potential predators also were more likely to use emergent macrophytes, but ordination indicated larvae and potential predators were differentially distributed along a vegetation structure-water depth gradient with larvae in shallow vegetated areas. Between-habitat differences appeared to be due to larval sucker selection for, or better survival in, emergent macrophytes, rather than differential access or exclusion from other habitats. The importance of emergent macrophytes appears to be related to increased foraging success and reduced predation. Because larvae in emergent macrophytes have a size and gut fullness advantage, the amount of emergent habitat could affect early survival. However, interannual differences in recruitment to the adult population may or may not be dependent on larval dynamics. Our results suggest larval sucker access to emergent macrophytes may be necessary, but perhaps not sufficient, for promoting good year class formation. [ABSTRACT FROM AUTHOR]

Condition factors and growth rates of postlarval (young-of-year) fishes in a Central California river were compared in order to determine the relative importance of floodplain and riverine habitats for rearing. Sampling took place between April and June of 2001 and 2002 in the lower Cosumnes River and its floodplain. Sacramento splittail showed higher condition and length increment in floodplain habitats of than in riverine habitats. Sacramento suckers showed differences in condition between sites, but suckers from the floodplain had lower weight increments than those from the river. The weight increment in Sacramento splittail was not significantly different between habitats. In addition, two alien species, common carp and golden shiner, had similar condition factors and growth rates. This study shows the usefulness of condition factor and growth rate in evaluating the importance of different habitats for early life history stages of fishes. [ABSTRACT FROM AUTHOR]

Hybridization with the introduced white sucker, Catostomus commerson, has been blamed in part for the decline of the Rio Grande sucker, C. plebeius, in the upper Rio Grande basin of Colorado and New Mexico but without convincing evidence. Here we report results from a genetic study of hybridization between the two species across their sympatric range in New Mexico. We used two nuclear microsatellite markers and one mitochondrial DNA marker to identify hybrids. These genetic methods detected no F1 or backcross hybrids in larvae, young-of-the-year or adults from the upper Rio Grande basin. This indicates that hybridization between the two species occurs rarely, if ever. [ABSTRACT FROM AUTHOR]

Fishes were collected in four mainstem reaches and eight tributary reaches in the Keya Paha River basin during May and June 2002. Most reaches were characteristically run habitats with sand substrates and riparian pastures. Data were combined with historical records to construct a basin-wide ichthyofaunal list which comprised 38 species from seven families. Dominant species were sand shiners (Notropis ludibundus; 47%), red shiners (Cyprinella lutrensis; 37%), and brassy minnows (Hybognathus hankinsoni; 8%). Dominant game species were bluegill (Lepomis machrochirus) and channel catfish (Ictalurus punctatus). We found one species previously listed as rare in South Dakota-plains topminnow (Fundulus sciadicus), and four species not previously found in the Keya Paha River - silver chub (Macrhybopsis storeriana), river carpsucker (Carpiodes carpio), northern pike (Esox lucius), yellow perch (Perca flavescens). [ABSTRACT FROM AUTHOR]

The sequencing analysis of the mitochondrial DNA control region (mtCR DNA) was performed to assess the genetic divergence and population structure of the Chinese sucker Myxocyprinus asiaticus (Cypriniformes Catostomidae) using four sample lots from natural populations of the Yangtze River. The mtCR DNA sequences of approximately 920 base pairs were obtained. A total of 223 nucleotide positions were polymorphic, and these defined 39 haplotypes. Of the 39 haplotypes, 37 (90%) were not shared, and among the populations as a whole there was little sharing of haplotypes. The average haplotype diversity (0.958) and the average nucleotide diversity (0.052) indicated a higher level of genetic diversity of Chinese sucker through the river. Analysis of molecular variation (AMOVA) of data revealed significant partitioning of variance (P < 0.001) among populations (60.29%), and within populations (39.71%). The topology according to the neighbor joining and maximum parsimony methods showed mosaic composition of the 39 haplotypes, suggesting that the populations were not completely divergent. The pairwise F statistic values, however, indicated that the population structuring existed to some extent among the geographic populations. There was a positive relationship between the aquatic distance and the genetic distance (Fst) among the populations (P < 0.05). Based on our data, it is suggested that genetic drift, gene flow, and stochastic events are the possible factors influencing the population structure and genetic variation. [ABSTRACT FROM AUTHOR]

In early May, 1-m sections of trembling aspen (Populus tremuloides Michx.) roots in a forest cutblock were carefully exposed and examined for damage. Undamaged roots were subjected to one of three wounding treatments (scrape, sever, or uninjured control) and were then reburied to either the full normal organic layer depth or to one third of the normal depth. Following one growing season, the roots were reexposed and assessed for aspen sucker numbers and growth rates. Results indicate that injured roots produced suckers nearly twice as often as uninjured roots. Further, injured roots produced more suckers per root, and these suckers were taller and had greater leaf area. Roots buried under shallow organic layers also generated more suckers, regardless of injury type. The side of injury (distal or proximal) did not affect any of the measured variables. The present study suggests that moderate wounding of aspen roots increases initial sucker numbers and growth rates. [ABSTRACT FROM AUTHOR]

We studied growth, condition, spawning period, activity patterns, and movement in the Salish Suckers of Pepin Brook in British Columbia's Fraser Valley. Radiotelemetry showed that fish were crepuscular, had home ranges averaging 170 m of linear channel, made their longest movements during the spawning period (March to early July), and rarely crossed beaver dams. Relative to closely related catostomids, Salish Suckers are small, early maturing, and have a prolonged spawning period. These characteristics are likely to impart good resilience to short-term disturbances of limited spatial scale and to facilitate successful reintroductions to suitable habitat. The chronic, large-scale disruptions that affect their habitat in Canada, however, are likely to cause further extirpations over time. Given its limited geographic distribution, management of the Salish Sucker should focus on protecting all remaining habitat and exploiting opportunities for habitat restoration and reintroduction into suitable habitats throughout their historic range. [ABSTRACT FROM AUTHOR]

Examines cestodes of peruvian freshwater stingrays. Analysis of the histological sections of the cysts; Presence of a scolex bearing suckers and apical organ; Characterization of ribosomal DNA.

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. [ABSTRACT FROM AUTHOR]

We conducted swimming performance tests on native and nonnative fishes commonly found in Arizona streams to evaluate the extent of differences in swimming ability among species. Fishes with similar mean lengths were subjected to stepwise increases in water velocity in a laboratory swim tunnel until fish could no longer maintain position. Nonnative fathead minnows Pimephales promelas and red shiners Cyprinellalutrensis exhibited swimming abilities similar to native longfin dace Agosia chrysogaster, speckled dace Rhinichthys osculus and spikedace Meda fulgida. Nonnative mosquitofish Gambusia affinis exhibited swimming ability similar to native Gila topminnows Poeciliopsis occidentalis. Desert suckers Catostomus clarki, bluehead suckers Catostomus discobolus and speckled dace exhibited behavioral responses to high water velocities that may confer energetic advantages in swift water. Differences in swimming ability do not appear to adequately explain the disproportionate removal of nonnative fishes via flooding. Behavioral responses to high flows are more likely the mechanism that allows native fish to persist in streams during flood events. [ABSTRACT FROM AUTHOR]

Abstract Aim To assess the roles of dispersal and vicariance in shaping the present distribution and diversity within Hypentelium nigricans , the northern hogsucker (Teleostei: Cypriniformes). Location Eastern United States. Methods Parsimony analyses, Bayesian analyses, pairwise genetic divergence and mismatch plots are used to examine patterns of genetic variation across H. nigricans . Results Species relationships within the genus Hypentelium were consistent with previous hypotheses. However, relationships between haplotypes within H. nigricans revealed two deeply divergent groups, a clade containing haplotypes from the New and Roanoke rivers (Atlantic Slope) plus Interior Highlands and upper Mississippi River and a clade containing haplotypes from the Eastern Highlands, previously glaciated regions of the Ohio and Wabash rivers, and the Amite and Homochitto rivers of south-western Mississippi. Main conclusions The phylogenetic history of Hypentelium was shaped by old vicariant events associated with erosion of the Blue Ridge and separation of the Mobile and Mississippi river basins. Within H. nigricans two clades existed prior to the Pleistocene; a widespread clade in the pre-glacial Teays-Mississippi River system and a clade in Cumberland and Tennessee rivers. Pleistocene events fragmented the Teays-Mississippi fauna. Following the retreat of the glaciers H. nigricans dispersed northward into previously glaciated regions. These patterns are replicated in other clades of fishes and are consistent with some of the predictions of Mayden's (Systematic Zoology, 37, 329, 1988) pre-Pleistocene vicariance hypothesis. [ABSTRACT FROM AUTHOR]

Herein we describe a simple method for developing species-diagnostic markers that would permit the rapid identification of hybrid individuals. Our method relies on amplified length polymorphism (AFLP) and single strand conformation polymorphism (SSCP) technologies, both of which can be performed in any molecular biology facility using standard laboratory equipment. We demonstrate the utility of the AFLP-SSCP method by developing three taxon-specific markers that will be suitable for monitoring introgression in endangered Klamath basin suckers. [ABSTRACT FROM AUTHOR]

Abstract Blue sucker Cycleptus elongatus (L.) in the upper Yazoo River basin, Mississippi, USA was studied using overnight hoop net sets (n = 4093) during 1988 and 1990–1998 to determine the influence of channel dredging. There were 264 blue suckers captured, ranging from 3 to 11 years of age. Length ranged from 265 to 700 mm and weight from 120 to 4700 g. Concurrent studies with smaller mesh hoop nets failed to capture any juvenile blue suckers. Catch-per-unit-effort (CPUE: fish net-1 ) declined throughout the study in the Yalobusha River, a river subjected to channel dredging during 1988 and 1994. With the exception of limited hydraulic dredging in the Tallahatchie River, there was no dredging in the other Yazoo River tributaries, nor were there declines in blue sucker catch rates in these rivers. Throughout the upper Yazoo River basin, blue sucker stocks were dominated by adult fish, and there was little evidence of reproduction or recruitment. Conservation of the blue sucker in the upper Yazoo River basin should include actions that ensure the functional integrity of this floodplain river ecosystem and elimination of channel dredging throughout the basin. [ABSTRACT FROM AUTHOR]

Presents a study which investigated the abundance biological characteristics of the blue sucker in the James River and the Big Sioux River, South Dakota. Materials and methods; Results; Discussion.

A recent phylogenetic study based on morphological, biochemical and early life history characters resurrected the genus Scartomyzon (jumprock suckers, c. eight–10 species) from Moxostoma (redhorse suckers, c. 10–11 species) and advanced the understanding of relationships among species in these two genera, and the genealogical affinities of these genera with other evolutionary lineages within the tribe Moxostomatini in the subfamily Catostominae. To further examine phylogenetic relationships among moxostomatin suckers, the complete mitochondrial (mt) cytochrome b gene was sequenced from all species within this tribe and representative outgroup taxa from the Catostomini and other catostomid subfamilies. Phylogenetic analysis of gene sequences yielded two monophyletic clades within Catostominae:Catostomus +Deltistes+Xyrauchen+Erimyzon+Minytrema andMoxostoma + Scartomyzon+Hypentelium+Thoburnia. Within the Moxostomatini,Thoburnia was either unresolved or polyphyletic; Thoburnia atripinnis was sister to a monophyleticHypentelium . In turn, this clade was sister to a monophyletic clade containing Scartomyzon andMoxostoma . Scartomyzon was never resolved as monophyletic, but was always recovered as a polyphyletic group embedded within Moxostoma, rendering the latter genus paraphyletic if ‘ Scartomyzon ’ continues to be recognized. Relationships among lineages within theMoxostoma and ‘ Scartomyzon ’ clade were resolved as a polytomy. To better reflect phylogenetic relationships resolved in this analysis, the following changes to the classification of the tribe Moxostomatini are proposed: subsumption of ‘ Scartomyzon ’ into Moxostoma; restriction of the tribe Moxostomatini to Moxostoma; resurrect the tribe Erimyzonini, containing Erimyzon andMinytrema , classified as incertae sedis within Catostominae; retain the tribe Thoburniini. Copyright 2002 The Fisheries Society of the British Isles. Published by Elsevier Science Ltd. All rights reserved. [Copyright &y& Elsevier]

The influence of three propagation practices and three corm types of enset on the production of suckers was investigated. After removal of apical buds, mother corms were uprooted and immediately replanted, not uprooted from original positions and uprooted and transferred to new planting holes three months later. Three corm types: whole, halved and quartered corms were used. Suckers were harvested one year after removal of apical buds. After harvest, the suckers were sorted into three size groups: undersized, small and medium to large. The number of suckers produced per plot, from four planting holes, ranged from 40 to 141 depending on the treatments. Halved and quartered mother corms, when transferred to new planting holes three months after removal of apical buds, produced fewer suckers. On the other hand, the halved corms, when uprooted and replanted immediately after removal of apical buds or not uprooted from their original growing sites, gave earlier differentiation of buds and produced more suckers. The halved corms also gave more medium to large suckers than whole and quartered corms when evaluated across all the propagation methods. An increase in the number of vigorous suckers from halved corms is possible because of elimination of the strong apical dominance while leaving reasonable portions of the mother corm to sustain initiation, growth and development of suckers. Therefore, halved corms uprooted and immediately replanted or left in situ can be used to produce more suckers with better growth. [ABSTRACT FROM AUTHOR]

Investigations of a fish kill at an irrigation reservoir in the Deschutes River basin, Oregon, documented at least 153 dead largescale suckers Catostomus macrocheilus, all heavily infected with large Ligula intestinalis (Cestoda). Moribund fish nearshore were similarly infected, with no evidence of secondary disease or infection. Morbidity and mortality in all cases was probably due to severe mechanical damage to internal host organs resulting from infection with multiple, large L. intestinalis. The pathology of L. intestinalis documented in largescale sucker in this study contrasts sharply with previous accounts and may represent a new and emerging disease for largescale suckers. Copyright 2002 The Fisheries Society of the British Isles. Published by Elsevier Science Ltd. All rights reserved. [Copyright &y& Elsevier]

Presents a study that detected the historic levels of genetic diversity in the Chinese sucker (Myxocyrinus asiaticus Bleeker) by using DNA fingerprinting on blood samples collected between 1949 and 1952. Comparison of the historic DNA with that of breeding stock from 2002; Impact of overfishing and large dams on the wild populations of the Chinese sucker; Demonstration of reduced genetic variability in a farmed population of the Chinese sucker by DNA fingerprinting.

1. Larval net-winged midges (Diptera: Blephariceridae) possess six ventral suckers that enable them to inhabit swift streams. Each sucker consists of a suction disc and a cavity with a piston. Large muscles are inserted within the piston, as well as at the base of the suction disc. This structure infers that both attachment and release of the sucker is achieved by vertical movements of the piston. 2. Live observations of blepharicerid larvae revealed that the sucker is indeed attached by an upward movement of the piston, but that the cavity is flooded when the sucker is released. The piston is lowered only at the end of a sucker ‘step’, expelling water from the cavity. 3. During foraging, the maxilla and the piston of the first sucker are moved synchronously, indicating that the first sucker functions as a holdfast thus facilitating grazing. 4. The adhesive forces, as well as the relative size of blepharicerid suckers, differ amongst species. They are highest in Hapalothrix lugubris and lowest in Liponeura cordata, which correlates with the hydraulic stress to which the larvae of these species are exposed in their preferred habitat. The balance between the efficiency of their retention structure and the hydraulic conditions of their preferred habitat defines a key dimension of their ecological niche. [ABSTRACT FROM AUTHOR]

This article presents information related to thallium concentration in lake trout from Lake Michigan. The average concentration of thallium in 37 lake trout samples was determined to be 140.8 ± 110.5 ng/g wet weight and is similar to reported values for brook trout, white sucker and yellow perch in the Adirondack lakes in the U.S. Assuming that the dry weight concentration of thallium in biota is ten times higher than the wet weight concentration the dry weight concentration of thallium in lake trout is estimated to be approximately 1.5 mg/kg. The bioaccumulation factor of thallium in lake trout calculated to 10000, using an average thallium concentration in Lake Michigan water of 14 ng/L.