Historic and recent age structure and growth of endangered Lost River and shortnose suckers in Upper Klamath Lake, Oregon

Seventy-four lapilli from Lost River suckers captured in Upper Klamath Lake in 1970 during a snag fishery on spawning adults and 192 lapilli from adults sacrificed from 2001–2006 were examined to determine age and growth parameters; lapilli from 165 shortnose suckers sacrificed from Upper Klamath Lake from 2001–2006 were also examined. Relative marginal distance analyses indicated that growth marks were annuli and formed in December–January. Lost River suckers from the historic collection were aged to 57 years, while Lost River and shortnose suckers from the recent collection were aged to 40 years and 24 years, respectively. Larger and older Lost River suckers were represented in the historic collection compared to the recent collection. Uncoupling of otolith length and fish length in Lost River suckers as well as a large spread in the predicted age- at-size for shortnose suckers precluded the ability to back-calculate size-at-age. Likelihood ratio tests indicated the growth model parameters were significantly different at both the sex and collection level. Growth in body length for both species appeared determinate in that growth was rapid until maturity, and then slowed over several years until growth in length was nearly nonexistent; a 650–700 mm Lost River sucker could be between 14 and 57 years old, while a 460 mm shortnose sucker could range from 12–24 years old. In contrast, while growth in body length slowed for both species, body mass continued to increase. This growth strategy, which is also found in other western lake suckers, may allow for more energy to be utilized for reproduction and help populations persist in spite of years of limited recruitment or recruitment failure.     

Abundance,size, and feeding success of larval shortnose suckers and Lost River suckers from different habitats of the littoral zone of Upper Klamath Lake

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.     

Postglacial dispersal of longnose suckers, Catostomus catostomus, in the Mackenzie and Yukon Drainages

The role played by stream transfers and reversals in the postglacial dispersal of fish populations in the Yukon and Mackenzie River drainages of Canada was analysed using genetic and meristic data from longnose sucker (Catostomus catostomus Forrester) populations. The hypothesis the suckers dispersed from the Yukon River into the Mackenzie River via the Peel River was evaluated. Meristic data (gill rakers and lateral line scales) were uninformative for this analysis. Genetic affinity between the Yukon River and upper Peel River populations, and between Mackenzie and lower Peel River populations is suggested by transferrin allele frequencies. These affinities support the view that longnose suckers inhabiting the middle and upper regions of the Peel River are derived from Beringian and Mississippian ancestors, while suckers in the lower Peel are descended from Mississippian stock. Evidence for dispersal by way of the Eagle River was not found. Affinities of sucker populations in other river systems in the region are also described.     

Serum calcium concentrations in white sucker, Catostomus commersoni Lacepède, and bluegill, Lepomis macrochirus Rafinesque, in northern Wisconsin lakes: relation to pH and waterborne calcium

We measured serum calcium concentrations in mature white suckers and bluegills collected from clear-water Wisconsin lakes before spawning. The mean serum calcium concentration in female white suckers was greater in a circumneutral lake than in two naturally acidic lakes, whereas mean concentrations in fish from the two acidic lakes did not differ. Serum calcium concentrations in female bluegills from four acidic and four circumneutral lakes varied among lakes, but no relation was apparent between serum calcium level and either lake pH or waterborne calcium. In contrast, a strong negative correlation between mean serum calcium concentration and relative density of bluegill populations in the eight lakes was observed, suggesting that serum calcium levels in this species are affected by density-dependent factors. Mean serum calcium concentrations were substantially lower in mature male bluegills than in females, which is the norm prior to spawning. We hypothesized that serum calcium levels in female white suckers are depressed by exposure to pH 6.0 or less in calcium-poor waters. The utility of serum calcium concentrations, measured before spawning, as a measure of pH-related stress on populations of white suckers and other synchronous spawners merits further study. However, this measure is probably not useful for evaluating acid stress on fish species such as the bluegill, which have asynchronous reproductive cycles.     

Recent,small beginnings: genetic analysis suggests Catostomus rimiculus (Klamath smallscale sucker) in the Smith River,California, are introduced

Identification of introduced species can be important to understanding ecological systems and meeting conservation and management goals, but the process can be surprisingly challenging. The Klamath smallscale sucker Catostomus rimiculus seems likely to be native to the Smith River because the drainage separates two basins believed to be within the fish's native range, the Rogue and Klamath rivers. Further, C. rimiculus is broadly distributed in the Smith River, and the indigenous Dee-ni’ People of the Smith River have a unique word for sucker. Nonetheless, a historical survey of fishes that described C. rimiculus from the Rogue and Klamath rivers did not include C. rimiculus among the fishes of the Smith River. To determine whether the genetic structure of the Smith River C. rimiculus reflects expectations for a native sucker population, the authors of this study examined variation in microsatellite and mitochondrial genetic markers from the Smith River and surrounding drainages. The genetic analyses revealed a pattern consistent with extreme founder effects in Smith River C. rimiculus, as would be expected from a single introduction of six or fewer effective individuals. The sharing of a high-frequency haplotype between the Smith River and Klamath River that is not detected in the Rogue River suggests the Klamath River as the likely source for the introduction. The findings highlight that local-scale introductions can be easily overlooked because the newly established populations can appear to be parts of contiguous natural distributions.     

Microsatellite markers for the June sucker (Chasmistes liorus mictus), Utah sucker (Catostomus ardens), and five other catostomid fishes of western North America

We developed and optimized five new microsatellite markers for the genetic management of the endangered June sucker. We report the cross‐amplification of these markers, and seven microsatellites previously developed for Klamath Basin suckers, in seven catostomid species of western North America. No linkage disequilibrium was detected between pairs of loci. Since most of these loci exhibited conserved priming sites, they may be useful for landscape‐scale studies of speciation and patterns of gene flow among multiple sucker lineages.     

Methylparathion, carbaryl and aldrin impact on nitrogen metabolism of prawn, Penaeus indicus

Changes in hepatopancreas, muscle and gill tissue nitrogen metabolic profiles were studied in a penaeid prawn, Penaeus indicus, following its exposure to sublethal concentrations of methylparathion, carbaryl and aldrin. In all the insecticide exposed prawn tissues, Ammonia levels were significantly increased and a shift in the nitrogen metabolism towards the synthesis of urea and glutamine was observed. Inhibition of glutamate oxidation to ammonia and alpha-ketoglutarate by glutamate dehydrogenase suggests a mechanism whereby hyperammonemia is reduced by minimizing the addition of further ammonia to the already existing elevated ammonia pool. Increased alanine and aspartate aminotransferases demonstrates the onset of gluconeogenesis. Mechanisms to detoxify the ammonia by enhancing the synthesis of urea and glutamine at the cellular level was observed in the selected tissues pave way for the survivability of prawns in insecticide polluted environs.     

Development of a quantitative assay to measure expression of transforming growth factor β (TGF-β) in Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) and evaluation of potential pitfalls in use with field-collected samples

The Nature Conservancy is in the process of restoring the Williamson River Delta in an attempt to recreate important juvenile habitat for the endangered shortnose sucker Chasmistes brevirostris and the endangered Lost River sucker Deltistes luxatus. Measurement of TGF-β mRNA expression level was one of the indicators chosen to evaluate juvenile sucker health during the restoration process. TGF-β mRNA expression level has been correlated with disease status in several laboratory studies and TGF-β mRNA expression level has been used as a species-specific indicator of immune status in field-based fish health assessments. We describe here the identification of TGF-β and a possible splice variant from shortnose sucker and from Lost River sucker. The performance of a quantitative RT-PCR assay to measure TGF-β mRNA expression level was evaluated in field-collected spleen and kidney tissue samples. The quality of extracted RNA was higher in tissues harvested in September compared to July and higher in tissues harvested at lower temperature compared to higher temperature. In addition, the expression level of both TGF-β and 18S as assessed by qRT-PCR was higher in samples with higher quality RNA. TGF-β mRNA expression was lower in kidney than in spleen in both Lost River sucker and shortnose sucker.     

Cypermethrin induced changes in nitrogen metabolism of fish, Tilapia mossambica

At sublethal concentrations, cypermethrin caused a decrease in total proteins and an increase in free amino acids, protease, alanine aminotransferase and aspartate aminotransferase in liver, brain and gill tissues of Tilapia mossambica. Nitrogen metabolic profiles like ammonia, urea and glutamine were also elevated in all the tissues as a consequence of cypermethrin toxicity. Glutamate dehydrogenase, AMP deaminase and adenosine deaminase activity was also increased in the present study.     

Regression,proliferation and development of lip papillomas in wild white suckers,Catostomus commersoni,held in the laboratory

Synopsis Epizootics of skin neoplasms in teleost species have been documented within the Great Lakes region over the last decade. The white sucker,Catostomus commersoni, has been proposed as a sentinel species to monitor environmental health in these systems. The prevalence of skin neoplasia is elevated in white suckers and other fish taken from chemically polluted sites or from lake regions adjacent to heavy industry. Lip papillomas regress and proliferate spontaneously in captive wild suckers. It is important to investigate the relevance of these observations to papilloma etiology to determine whether the prevalence of this disease is a suitable biomarker for environmental health. White suckers were captured in the spring of 1992 and 1993 during annual spawning runs (mid to late April) at the Ganaraska River, which discharges into Lake Ontario at Port Hope, Ontario. Under crowded laboratory conditions, there was either proliferation of existing papillomas or development of new papillomas. However, in uncrowded conditions, existing papillomas either regressed completely or there was no development of new papillomas. Protein Kinase C (PKC), a proposed marker enzyme for hyperplasia and neoplasia, was used to determine if regressing and proliferating papillomas could be differentiated on the basis of biochemical activity. PKC activity was lower in proliferating papillomas, but not significantly different from papillomas sampled initially from Ganaraska River suckers. Regressing papillomatous tissue displayed a significantly higher level of enzyme activity than either proliferating or unchanged papillomas, but the PKC activity of regressing papillomas was not significantly different from that of normal lip epidermis.     

Infection by a black spot-causing species of Uvulifer and associated opercular alterations in fishes from a high-desert stream in Wyoming

Black spot is a common disease syndrome of freshwater fishes. This study provides information on the rank of density of the black spot agent and opercular bone alterations associated with at least one digenean, Uvulifer sp., infecting native and non-native catostomids and cyprinids of the Upper Colorado River Basin. We evaluated the density rank of pigmented metacercariae and associated alterations in the operculum of the bluehead sucker Catostomus discobolus, flannelmouth sucker C. latipinnis, white sucker C. commersoni, catostomid hybrids, roundtail chub Gila robusta, and creek chub Semotilus atromaculatus, sampled from Muddy Creek, Wyoming, USA in 2003 or 2004. All fish species contained individuals that exhibited gross signs of the black spot agent. Bluehead and flannelmouth suckers had 100% prevalence of infection. Although the other suckers and chubs contained encysted metacercariae in at least one individual, the presence of pigmented metacercariae was not apparent (i.e. based on gross observations) in many individuals. Catostomids had higher densities of metacercariae than cyprinids, as shown by frequency distributions of density ranks. Opercular holes (i.e. holes that completely penetrated the opercle and were in direct association with the pigment associated metacercariae) and pockets (depressions on the external surface of the opercle associated with metacercariae) were abundant among catostomids but rare among cyprinids.     

Concentrations and distribution of Fe,Zn and Cu in tissues of the white sucker (Catostomus commersoni) in relation to elevated levels of metals and low pH

This study examines whether the process of lake acidification influences the accumulation of Fe, Zn and Cu in the tissues of the white sucker (Catostomus commersoni). Concentrations of Fe, Zn and Cu were measured in the liver, kidney and muscle of white sucker sampled from 4 acidic (pH range 4.8–5.3), 1 slightly acidic (pH = 5.8) and 3 circumneutral (pH = 6.3, 6.4) lakes located in south-central Ontario, Canada. Pearson product-moment correlation coefficients were used to determine relationships between average elemental concentrations in the 3 tissues and both sediment and water metal concentrations plus lake pH, DOC and alkalinity. Despite the 1000-fold difference in H+ concentration among the 8 study lakes, tissue concentrations of Fe, Zn and Cu did not correlate with lake pH. Average Fe, Zn and Cu tissue concentrations did not correlate with metal concentrations in lake water. Only Zn concentrations in the liver and muscle were correlated with Zn concentrations in the sediment (r = 0.83 and r = 0.88, P < 0.05). Iron and Cu were regulated by the white sucker over a wide range of lake pH and metal concentrations in both the water and sediment. In contrast, Zn tissue concentrations were correlated with sediment Zn concentrations, the latter are thought to result from Zn inputs of anthropogenic origin.     

Thermal stratification and benthic foraging patterns of white sucker

Abundances of white sucker, 100–500 mm FL, were not significantly different among the epilimnia, metalimnia and portions of the hypolimnia shallower than 20 m in each of two lakes. However, small suckers < 200 mm were captured most frequently in the epilimnion and no white suckers were captured in the deepest region, 20–38 m, of the two lakes. White suckers consumed prey from all three temperature zones in each lake. Prominent food items were Hyalella azteca and the chironomid larvae Heterotrissocladius, Djalmabatista and Procladius. Despite differences in relative densities of benthic invertebrates among thermal zones of the two lakes, suckers in neither lake foraged exclusively on prey of epilimnetic origin. Suckers captured in the metalimnia foraged on invertebrates that were common to all three thermal zones. And, only 0–4% of the suckers captured in the hypolimnia of the two lakes contained prey that were unique to the epilimnia. Suckers caught in the hypolimnia mainly consumed deep water invertebrates; 83% of the suckers foraged in the metalimnion and hypolimnion of Islets Lake and 45% foraged in the hypolimnion in Burnt Island Lake. Consequently there was little evidence of a massive inshore feeding migration followed by a post-feeding return to the hypolimnion. Northern pike and lake trout rarely fed on white suckers in these lakes and thus piscivory was an unlikely factor in the observed distribution of suckers.     

Shifts in protein metabolism in some organs of freshwater fish, Cyprinus carpio under mercury stress

Changes in the protein metabolism of gill, kidney and intestine of freshwater fish, Cyprinus carpio exposed to 1, 15 and 30 days to sublethal concentration (0.1 mg/l) of mercury were studied. The total, soluble and structural protein contents recorded the depletion followed by progressive increase in accumulation of free aminoacids. Concurrently, the activity of protease in the tissues was also increased. A steady enhancement in the activities of aspartate aminotransferase and alanine aminotransferase paralleled the elevation of glutamate dehydrogenase activity in the organs studied. Levels of ammonia and urea have also reported elevation. All these changes clearly documented the induction of severe proteolysis. The magnitude of these changes increased overtime. These changes were more in the gill at the initial periods of exposure (1 and 15 days), but as the period of exposure increased, these changes were more pronounced in the kidney at 30 days of exposure to sublethal concentration of mercury.     

Rangewide molecular structuring in the Utah sucker (Catostomus ardens)

The Utah sucker (Catostomus ardens) is endemic to the Bonneville Basin and the upper Snake River drainage in western North America, and is thought to hybridize with the federally endangered June sucker (Chasmistes liorus mictus) in Utah Lake (Bonneville Basin). Here we describe the discovery of a major subdivision in Utah suckers (4.5% mitochondrial sequence divergence) between the ancient Snake River drainage and the Bonneville Basin. This boundary has not previously been recognized in Utah suckers based on morphologic variation, but has been recently described in two endemic cyprinids in the region. Populations in valleys east of the Wasatch Mountains in Utah clustered with the Snake River populations, suggesting that these valleys may have had an ancient hydrologic connection to the Snake River. We also found evidence of population isolation within the Bonneville Basin, corresponding to two Pleistocene sub-basins of the ancient Lake Bonneville. In contrast, we found no molecular evidence for deep divergence between Utah suckers and June suckers in Utah Lake or for a history of hybridization between divergent lineages in that population, although we recognize that demographic events may have obscured this signal. These findings suggest that the morphological differences between Utah and June suckers in Utah Lake may be the result of strong, and relatively recent, ecological selection. In summary, morphological and molecular characters seem to vary along different axes in different portions of the range of this taxon, providing an interesting system for studying the contributions of neutral and adaptive variation to species diversity.     

Sublethal effects of endosulfan on the histology and protein pattern of Cyprinus carpio gill

Histological and protein pattern changes in the gill of the common carp, Cyprinus carpio were investigated following exposure to sublethal concentrations of the organochlorine insecticide, endosulfan. Hyperplasia, lamellar fusion, curling of the tips of primary lamellae, exudation of erythrocytes and bulging of the tips of primary lamellae were the histological lesions observed. Protein pattern of the gill varied at different sampling periods characterised by disappearance of certain fractions and occurrence of additional fractions. It was concluded that the severity of histological changes and protein pattern variations seen in the gill was dependent on both the duration of exposure and the concentrations of endosulfan used (over the range 5—25 % of the 96 hr LC₅₀ value, 5·199ppb).     

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.     

The sublethal effects of zinc at different water temperatures on selected haematological variables in Oreochromis mossambicus

Trace metals such as zinc play an important role in the normal metabolic functioning of all organisms. However, metals can become toxic if background concentrations are exceeded in the environment. This study investigated the sublethal effects of zinc on the haematology of Oreochromis mossambicus at different water temperatures. Fish were exposed to sublethal zinc (Zn) concentrations of 40μg/l (mean Zn concentration measured from the Mhlathuze River) for a period of 96h at different water temperatures representing the seasonal temperatures in the Mhlathuze River (18°C, 24°C, 28°C and 32°C). Exposure to zinc at 28°C and 32°C resulted in the most pronounced haematological changes in O. mossambicus. The erythrocytotic conditions found following exposure to Zn could be attributed to damage to the gill surface. The ensuing hypoxic conditions are alleviated through the release of large amounts of immature RBC into the circulatory system. The leucocytotic conditions support the findings of damage to the gill surface. The increased glucose concentrations were attributed to a general adaptation response whereby metabolites are mobilised to meet increased energy demands during periods of stress. The changes in Na⁺ and K⁺ levels in the plasma of O. mossambicus can be attributed to a combination of stimulation of Na-K ATPase activity, reduced membrane permeability in the gill tissue and leakage from cells into the blood, respectively.     

Biology of suckers: late-formed shoots in sugarcane

Suckers in sugarcane are tillers that form late in the growing season after the population of main stalks has been established. Their biology has rarely been studied, though unsubstantiated comments relating to their morphology, development and number are abundant. In this paper, the literature is reviewed and new experiments presented. Comparison of suckers, emerging plant and ratoon cane showed that suckers have a different leaf and stem morphology. Suckers have a greater diameter at their stem base and shorter and wider leaves than primary stalks of a similar age. In 1 ‐year‐old crops, suckers have been demonstrated to decrease the net sucrose concentration of harvested material by diluting sucrose in the main stalks. By comparing main stalks without suckers to those that have initiated suckers, evidence is presented that suckers may also be decreasing the sucrose content of the stalks from which they are growing. Genotypic and environmental factors influence sucker number. Several experiments were designed to identify environmental stimuli for suckering. Increased nitrogen, through application late in the growing season, was found to increase the numbers of suckers present. Manipulation of the light environment of main stalks showed that a change in light quality (but not necessarily quantity) stimulated suckering. Further work is underway to define how these environmental stimuli lead to sucker initiation and growth. Major scientific questions that should be addressed are: the identification of other potential environmental stimuli, how the signals are perceived and translated into sucker initiation, and why suckers have different morphology. The practical challenge is to combine the new information about sucker biology and develop from it strategies to alter agronomy and select new cultivars that results in decreased suckering.     

Development of Biomimetic Squid-Inspired Suckers

Biomechanical properties of squid suckers were studied to provide inspiration for the development of sucker artefacts for a robotic octopus.Mechanical support of the rings found inside squid suckers was studied by bending tests.Tensile tests were carried out to study the maximum possible sucking force produced by squid suckers based on the strength of sucker stalks,normalized by the sucking areas.The squid suckers were also directly tested to obtain sucking forces by a special testing arrangement.Inspired by the squid suckers,three types of sucker artefacts were developed for the arm skin of an octopus inspired robot.The first sucker artefact made of knitted nylon sheet reinforced silicone rubber has the same shape as the squid suckers.Like real squid suckers,this type of artefact also has a stalk that is connected to the arm skin and a ring to give radial support.The second design is a straight cylindrical structure with uniform wall thickness made of silicone rubber.One end of the cylinder is directly connected to the arm skin and the other end is open.The final design of the sucker has a cylindrical base and a concave meniscus top.The meniscus was formed naturally using the surface tension of silicone gel,which leads to a higher level of the liquid around the edge of a container.The wall thickness decreases towards the tip of the sucker opening.Sucking forces of all three types of sucker artefacts were measured.Advantages and disadvantages of each sucker type were discussed.The final design of suckers has been implemented to the arm skin prototypes.