Metorchis conjunctus (Cobbold, 1860) Looss, 1899 (Trematoda: Opisthorchiidae): isolation of metacercariae from fish hosts

1981 ◽  
Vol 59 (10) ◽  
pp. 2010-2013 ◽  
Author(s):  
Thomas G. Watson
Keyword(s):  
Density Gradient ◽  
Salvelinus Fontinalis ◽  
Domestic Cats ◽  
Catostomus Commersoni ◽  
Posterior Density ◽  
Semotilus Corporalis ◽  
Fish Hosts ◽  
Time Of Collection ◽  
Anterior Posterior

After 40 years Lac Edouard, Québec (46°45′ N, 72°55′ W), remains a focus of Metorchis conjunctus. Prevalence of infection differs for species of fish: Catostomus commersoni (100.0%), C. catostomus (81.8%), Semotilus corporalis (78.3%), and Salvelinus fontinalis (71.4%). All cysts isolated from S. fontinalis had a dense calcium coat.Many metacercariae, recovered after digestion of the fish in acid–pepsin solution, were viable and infective to domestic cats. Viability apparently depended on time of collection since more encysted larvae were found to be viable in October (32.4%) than in May (19.6%). Metacercariae of M. conjunctus were distributed in C. commersoni in an anterior–posterior density gradient. Anterior regions of the fish were more likely to be penetrated by the cercariae, based on both density and percent of metacercariae recovered. It is concluded, as a result of this study, that fish swim into clouds of cercariae which actively penetrate into the musculature of the fish.

Comparative Survival and Growth of Planted Wild, Hybrid, and Domestic Strains of Brook Trout (Salvelinus fontinalis) in Ontario Lakes

1981 ◽  
Vol 38 (12) ◽  
pp. 1672-1684 ◽  
Author(s):  
J. M. Fraser
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Wild Strain ◽  
Catostomus Commersoni ◽  
Precambrian Shield ◽  
Wild Hybrid ◽  
Wild Strains ◽  
Competitive Species ◽  
Survival And Growth ◽  
Shield Lakes

Matched plantings of domestic strain and interstrain hybrid (or wild strain) brook trout (Salvelinus fontinalis) were made annually in nine small Precambrian Shield lakes during 1973–77. Recoveries of planted fish were made by gillnetting and/or angling during 1974–80. In six study lakes, hybrids (and wild strains) were recovered at rates two to four times greater than the domestic strain; in three lakes recoveries were similar. Most domestic strain trout were caught in the year following planting whereas recoveries of hybrids and wild strains were spread over 3–4 yr. Each kilogram of hybrid (or wild) planted yielded 5.6 kg (1.2–12.3); each kilogram of domestic strain planted yielded 0.8 kg (0.2–2.1). Lakes containing only minnows and sticklebacks yielded the highest returns of brook trout; lakes containing competitive species yielded low returns. Rapid growth of brook trout occurred in lakes containing only minnows and sticklebacks; slowest growth was noted in lakes supporting white suckers (Catostomus commersoni). Domestic strain brook trout and the matched hybrid grew at approximately the same rate within a lake and in seven of the nine lakes ate the same food. The performance of the Nipigon × domestic hybrid qualifies it for consideration as a replacement for the domestic brook trout presently planted in Ontario lakes.Key words: planting, brook trout, trout strain, hybrid, Precambrian Shield, survival, stock

The glochidia of certain Unionidae (Mollusca) in Nova Scotia and their fish hosts

1975 ◽  
Vol 53 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Michael Wiles
Keyword(s):  
Nova Scotia ◽  
Fish Species ◽  
Host Species ◽  
Gasterosteus Aculeatus ◽  
Catostomus Commersoni ◽  
Pungitius Pungitius ◽  
Apeltes Quadracus ◽  
Early Fall ◽  
Fish Hosts ◽  
Nova Scotian

Morphological and morphometric comparisons among adult and glochidial unionids from two Nova Scotian locations showed that Anodonta implicata, A. cataracta cataracta, A. c. fragilis, Elliptio complanatus, and Lampsilis radiata radiata were present. Gravidity studies suggested that fully developed glochidia occur from September to May in Anodonta marsupia, for only 5–6 weeks in June and July in E. complanatus, and perhaps at least from spring to early fall in L. r. radiata. Seven of 12 fish species sampled bore glochidia, which were identified in five host species by comparisons of their shapes and dimensions with those of glochidia from adult clams. Results were as follows: A. c. cataracta in Catostomus commersoni in June only, A. implicata or A. c. cataracta in Gasterosteus aculeatus in May and June, Anodonta sp. in Apeltes quadracus and Pungitius pungitius in June, and E. complanatus in Fundulus diaphanus in June and July. Thus, no relationships between gravidity periods of adult clams and infestation periods of their fish hosts by their glochidia were evident for species of Anodonta.

Performance of Domestic, Hybrid, and Wild Strains of Brook Trout, Salvelinus fontinalis, after Stocking: the Impact of Intra- and Interspecific Competition

1990 ◽  
Vol 47 (12) ◽  
pp. 2278-2284 ◽  
Author(s):  
Stephanie Lachance ◽  
Pierre Magnan
Keyword(s):  
Interspecific Competition ◽  
Relative Abundance ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
White Sucker ◽  
Catostomus Commersoni ◽  
Oligotrophic Lakes ◽  
Wild Strains ◽  
The Impact ◽  
Response Variables

Wild and hybrid strains of brook trout, Salvelinus fontinalis, showed better rates of recovery (by angling) and yield (kilograms of fish recovered per kilogram planted) than a domestic strain, during the 2 yr following planting, in six small oligotrophic lakes of the Laurentian Shield. Native brook trout and white sucker, Catostomus commersoni, had a significant impact on planted brook trout. Recovery, percent of increment in weight and yield of each planted strain were inversely correlated with (1) the relative abundance of native brook trout, and (2) the occurrence of white sucker, supporting hypotheses of intra- and interspecific competition. Furthermore, the response variables were also inversely correlated with the number of potential competitors, indicating that the impact of native brook trout and white sucker was additive. The recovery in number of planted trout (both years and all strains) was approximately four times higher in lakes with effectively no competitors than in lakes containing both white sucker and native brook trout; the increase in weight was nearly three times higher, and the yield was more than nine times higher. The performances of planted fish were intermediate in the lake containing only native brook trout as competitor.

Interactions between Two Distantly Related Species, Brook Trout (Salvelinus fontinalis) and White Sucker (Catostomus commersoni)

1991 ◽  
Vol 48 (5) ◽  
pp. 857-867 ◽  
Author(s):  
Serge Tremblay ◽  
Pierre Magnan
Keyword(s):  
Spatial Distribution ◽  
Brook Trout ◽  
Food Habits ◽  
Littoral Zone ◽  
Salvelinus Fontinalis ◽  
Feeding Habits ◽  
White Sucker ◽  
Catostomus Commersoni ◽  
Allopatric Populations ◽  
Benthic Prey

We compared spatial distribution and food habits of an allopatric brook trout (Salvelinus fontinalis) population to one living sympatrically with white sucker (Catostomus commersoni) in two small oligotrophic lakes. Small brook trout (< 20 cm) of both sympatric and allopatric populations were more abundant in the littoral than in the offshore zone whereas large [Formula: see text] were found equally in both habitats in May. From June to August, small and large trout from both populations shifted to the offshore zone; this shift was more pronounced for small sympatric trout. Allopatric trout fed mainly on zoobenthos whereas sympatric trout fed mainly on zooplankton except small ones which ate mostly zoobenthos during May and June. White sucker (< 20 and [Formula: see text]) were generally found in the littoral zone, feeding mainly on zoobenthos. These results suggest that brook trout shifted their spatial distribution and/or their feeding habits in the presence of white sucker and that the nature of these interactions varied according to fish size. Diet overlap between trout and sucker was the lowest when the biomass of benthic prey in the littoral zone was lowest (July), indicating that the intensity of interaction among these species varies according to the abundance of food resources.

scholarly journals DEVELOPING AN INDEX OF SUSTAINABLE COLDWATER STREAMS USING FISH COMMUNITY ATTRIBUTES IN RIVER PHILIP, NOVA SCOTIA

2004 ◽  
Vol 42 (2) ◽  
Author(s):  
Yoichiro Kanno ◽  
John Leland MacMillan
Keyword(s):  
Nova Scotia ◽  
Water Temperature ◽  
Habitat Quality ◽  
Fish Community ◽  
Fish Assemblages ◽  
Salvelinus Fontinalis ◽  
Habitat Degradation ◽  
Physical Habitat ◽  
Catostomus Commersoni ◽  
Community Changes

An Index of Sustainable Coldwater Streams (ISCS) was developed to quantify fish community changes affected by water temperature and physical habitat quality for small streams in the River Philip Watershed, Nova Scotia. The ISCS was modified from an Index of Biotic Integrity (IBI) and intended for assessing the quality of streams as coldwater habitats. The calibration of the ISCS was thought useful since global warming and habitat degradation, two major aquatic threats in the coming era, could significantly reduce the amount of undisturbed coldwater streams in Nova Scotia; thus, a tool was necessary to identify fish species vulnerable to these threats and to monitor fish community changes in relation to water temperature and physical habitat quality. There was a strong negative correlation between water temperature and physical habitat quality, and water temperature increase and habitat degradation replaced coldwater fish assemblages dominated by salmonids with warmwater and/or tolerant fish assemblages, coupled with increased total species richness. The proposed ISCS is composed of five metrics: (1) number of fish species, (2) percent of individuals that are salmonids, (3) percent of individuals that are brook trout (Salvelinus fontinalis), (4) percent of individuals that are white sucker (Catostomus commersoni), and (5) percent of individuals that are catchable salmonids (age 2 years and older). The ISCS is a promising index to identify priority conservation areas and to monitor changes in aquatic environments.Dans le but de quantifier les changements dans les communautés de poissons touchées par la température de l’eau et la qualité de l’habitat physique pour les petits cours d’eau du bassin hydrographique de la rivière Philip, en Nouvelle-Écosse, on a élaboré un indice de qualité des petits cours d’eau comme habitats d’eaux froides (Index of Sustainable Coldwater Streams, ISCS). Cet indice, inspiré d’un indice de l’intégrité biotique (Karr, 1981; Lyons et al., 1996), vise à évaluer la qualité des ruisseaux en tant qu’habitats d’eaux froides. On a pensé qu’il serait utile de calibrer l’ISCS, compte tenu du réchauffement de la planète et de la dégradation de l’habitat, deux menaces importantes pour les milieux aquatiques qui pourraient réduire considérablement le nombre de ruisseaux d’eaux froides non perturbés en Nouvelle-Écosse; c’est pourquoi il fallait un outil pour identifier les espèces de poissons vulnérables à ces menaces et pour surveiller les changements dans les communautés de poissons en rapport avec la température de l’eau et la qualité de l’habitat physique. On a observé une forte corrélation négative entre la température de l’eau et la qualité de l’habitat physique; de plus, l’augmentation de la température de l’eau et la dégradation de l’habitat avaient pour effet le remplacement d’assemblages de poissons d’eaux froides dominés par les salmonidés par des assemblages de poissons d’eaux tièdes ou tolérants avec une augmentation de la richesse totale en espèces. L’ISCS proposé comprend cinq paramètres : 1) le nombre d’espèces de poissons; 2) le pourcentage d’individus qui sont des salmonidés; 3) le pourcentage d’individus qui sont des ombles de fontaine (Salvelinus fontinalis); 4) le pourcentage d’individus qui sont des meuniers noirs (Catostomus commersoni) et 5) le pourcentage d’individus qui sont des salmonidés exploitables (âgés d’au moins deux ans). L’ISCS est un indice prometteur pour l’établissement de zones de conservation prioritaires et la surveillance des changements dans les milieux aquatiques.

Response of fish communities to different levels of white sucker (Catostomus commersoni) biomanipulation in five temperate lakes

2001 ◽  
Vol 58 (10) ◽  
pp. 1998-2010 ◽  
Author(s):  
Philippe Brodeur ◽  
Pierre Magnan ◽  
Michel Legault
Keyword(s):  
Fish Species ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Fish Communities ◽  
White Sucker ◽  
Age At Maturity ◽  
Catostomus Commersoni ◽  
Mass Removal ◽  
Males And Females ◽  
Different Levels

The goal of this study was to evaluate the response of white sucker (Catostomus commersoni), brook trout (Salvelinus fontinalis), and other fish species to the mass removal of white sucker in five Québec (Canada) lakes. White sucker removal ranged from 14.2 kg·ha–1 to 31.3 kg·ha–1 3 years after mass removal. In four of the study lakes, the proportion of 2+ to 4+ white sucker increased following mass removal. Mean catch and biomass per unit of effort of 1+ brook trout increased significantly in the lakes where white sucker removal was highest. All white sucker populations experienced growth increases after mass removal, and improved brook trout growth was observed in lakes where the most intensive mass removal occurred. These growth increases led to higher mean length at maturity in white sucker females and decreases in mean age at maturity in white sucker males and brook trout males and females. Mean adjusted fecundity significantly increased in white sucker and brook trout in lakes where mass removal was most intense. The present study suggests that white sucker and brook trout exhibit compensatory responses following a reduction of intra- and inter-specific competition and that these responses are related to the intensity of mass removal.

Effects of the introduction of white sucker, Catostomus commersoni, on the parasite fauna of brook trout, Salvelinus fontinalis

1996 ◽  
Vol 74 (7) ◽  
pp. 1304-1312 ◽  
Author(s):  
Nicole Dubois ◽  
Pierre Magnan ◽  
David J. Marcogliese
Keyword(s):  
Brook Trout ◽  
Parasite Species ◽  
Salvelinus Fontinalis ◽  
Feeding Habits ◽  
Parasite Fauna ◽  
White Sucker ◽  
Catostomus Commersoni ◽  
Local Factors ◽  
The Impact ◽  
Trout Feeding

White sucker, Catostomus commersoni, has been introduced in many brook trout, Salvelinus fontinalis, lakes of the Laurentian Shield, Quebec, Canada. The goal of this study was to assess the impact of these introductions on the parasite fauna of brook trout. Three lakes containing brook trout only and three lakes containing both brook trout and white sucker were studied. The objectives were (i) to determine if white sucker parasites were able to colonise the relatively oligotrophic lakes of the Laurentian Shield, (ii) to establish if parasites were exchanged between sucker and trout, and (iii) to study the effect of trout feeding habits on their parasite fauna, since this fish shifts its diet from zoobenthos to Zooplankton when living with white sucker. Eight of the 12 parasite species found on white sucker probably colonised the lakes with their host. Among the 11 parasite species identified from trout, it is unlikely that any were introduced by white sucker. Trout living with white sucker have more parasites transmitted by Zooplankton (Diphyllobothrium ditremum and Eubothrium salvelini) and fewer parasites transmitted by zoobenthos (Crepidostomum farionis and Sterliadochona ephemeridarum) than trout living in allopatry. Local factors such as lake morphometrics also seemed to play an important role in the composition of the trout parasite fauna.

Sea Lamprey (Petromyzon marinus) Predation on Freshwater Teleosts

1973 ◽  
Vol 30 (5) ◽  
pp. 601-605 ◽  
Author(s):  
G. J. Farmer ◽  
F. W. H. Beamish
Keyword(s):  
Salvelinus Fontinalis ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Salvelinus Namaycush ◽  
Coregonus Clupeaformis ◽  
Catostomus Commersoni ◽  
Caudal Peduncle ◽  
Pectoral Fins ◽  
Ictalurus Nebulosus ◽  
Freshwater Teleosts

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

Activated Prominences; Mechanisms for Activation and Eruption

1979 ◽  
Vol 44 ◽  
pp. 307-313
Author(s):  
D.S. Spicer
Keyword(s):  
Pressure Gradient ◽  
Density Gradient ◽  
Current Density ◽  
Convective Instability ◽  
Tearing Mode ◽  
Magnetic Shear ◽  
Long Wavelength ◽  
Ideal Mhd ◽  
Gradient Change ◽  
Accelerated Particles

A possible relationship between the hot prominence transition sheath, increased internal turbulent and/or helical motion prior to prominence eruption and the prominence eruption (“disparition brusque”) is discussed. The associated darkening of the filament or brightening of the prominence is interpreted as a change in the prominence’s internal pressure gradient which, if of the correct sign, can lead to short wavelength turbulent convection within the prominence. Associated with such a pressure gradient change may be the alteration of the current density gradient within the prominence. Such a change in the current density gradient may also be due to the relative motion of the neighbouring plages thereby increasing the magnetic shear within the prominence, i.e., steepening the current density gradient. Depending on the magnitude of the current density gradient, i.e., magnetic shear, disruption of the prominence can occur by either a long wavelength ideal MHD helical (“kink”) convective instability and/or a long wavelength resistive helical (“kink”) convective instability (tearing mode). The long wavelength ideal MHD helical instability will lead to helical rotation and thus unwinding due to diamagnetic effects and plasma ejections due to convection. The long wavelength resistive helical instability will lead to both unwinding and plasma ejections, but also to accelerated plasma flow, long wavelength magnetic field filamentation, accelerated particles and long wavelength heating internal to the prominence.

Uranyl Acetate and Rotary Shadowing to Increase the Contrast of Small Aggregated Virus Particles

1969 ◽  
Vol 27 ◽  
pp. 424-425
Author(s):  
Lee F. Ellis ◽  
Richard M. Van Frank ◽  
Walter J. Kleinschmidt
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Uranyl Acetate ◽  
Interferon Inducer ◽  
Virus Particles ◽  
Staining Methods ◽  
Rotary Shadowing

The extract from Penicillum stoliniferum, known as statolon, has been purified by density gradient centrifugation. These centrifuge fractions contained virus particles that are an interferon inducer in mice or in tissue culture. Highly purified preparations of these particles are difficult to enumerate by electron microscopy because of aggregation. Therefore a study of staining methods was undertaken.

Sign in / Sign up

Export Citation Format

Share Document