The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Patrice Couture - One of the best experts on this subject based on the ideXlab platform.
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seasonal variations in tissue metabolic capacities of yellow Perch perca flavescens from clean and metal contaminated environments
Canadian Journal of Fisheries and Aquatic Sciences, 2003Co-Authors: Debbie Audet, Patrice CoutureAbstract:This study examined seasonal variations in tissue metal contamination and physiological condition of yellow Perch (Perca flavescens) from a clean lake (Halfway Lake) and a metal-contaminated enviro...
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effects of environmental metal contamination on the condition swimming performance and tissue metabolic capacities of wild yellow Perch perca flavescens
Canadian Journal of Fisheries and Aquatic Sciences, 2002Co-Authors: James W Rajotte, Patrice CoutureAbstract:In this study, the general condition, swimming capacities, and tissue metabolic capacities and metal concentrations in wild yellow Perch (Perca flavescens) were examined from a range of metal-conta...
Joseph B Rasmussen - One of the best experts on this subject based on the ideXlab platform.
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shifts in the trophic ecology of brook trout resulting from interactions with yellow Perch an intraguild predator prey interaction
Transactions of The American Fisheries Society, 2009Co-Authors: David R Browne, Joseph B RasmussenAbstract:Abstract In size-structured populations, predator-prey interactions may be preceded by a phase of resource competition earlier in ontogeny, with potential consequences for population dynamics and resource management. We hypothesized that brook trout Salvelinus fontinalis and yellow Perch Perca flavescens would compete for shared resources and interact as predator and prey. We used stable isotopes and stomach content analysis to compare the trophic ecology of brook trout in lakes with and without yellow Perch. Percent littoral resource use by brook trout differed between Perch and nonPerch systems, ranging from approximately 50% to 100% in nonPerch lakes compared with 10-70% in Perch lakes. Nonpiscivorous-sized brook trout (fork length [FL] < 25 cm) showed a significant ontogenetic diet shift toward greater pelagic resource use during growth from 15 to 25 cm in sympatry with yellow Perch. Nonpiscivorous-sized brook trout in nonPerch lakes consumed a mixture of zoobenthos, zooplankton, and littoral prey fis...
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indirect effects of metal contamination on energetics of yellow Perch perca flavescens resulting from food web simplification
Freshwater Biology, 2005Co-Authors: Alison C Iles, Joseph B RasmussenAbstract:SUMMARY 1. Benthic invertebrate community composition and yellow Perch (Perca flavescens) diet, growth and activity levels from lakes along a metal-contamination gradient were used to assess the importance of a naturally diverse prey base for maintaining energy transfer to growing fish, and how this transfer is disrupted by metal contamination. 2. Zoobenthic communities had lower diversity in metal-contaminated lakes, with a notable absence of large bodied invertebrate taxa. 3. The average mass of non-zooplankton prey items was significantly greater for 2+ and 3+ Perch from the reference lake, and increased significantly with age in all except the most contaminated lakes where prey choice was limited. 4. Benthivorous Perch from all contaminated lakes exhibited slowed growth. Perch from one of the contaminated lakes exhibited faster growth during piscivory, indicating slowed growth only while benthivorous. 5. Estimates of fish activity, using the activity of the glycolytic enzyme Lactate dehydrogenase in Perch white muscle tissue as a proxy, suggested that shifts in diet to larger prey (in reference and intermediately contaminated lakes) lowered activity costs, which may explain how diet shifts maintain growth efficiency as Perch grow larger.
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influence of lake chemistry and fish age on cadmium copper and zinc concentrations in various organs of indigenous yellow Perch perca flavescens
Canadian Journal of Fisheries and Aquatic Sciences, 2004Co-Authors: Anik Giguere, Peter G C Campbell, Landis Hare, Gordon D Mcdonald, Joseph B RasmussenAbstract:Concentrations of Cd, Cu, and Zn were determined in various organs of juvenile yellow Perch (Perca flavescens) collected from eight lakes located along a metal concentration gradient. Metal exposur...
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bioenergetic costs of heavy metal exposure in yellow Perch perca flavescens in situ estimates with a radiotracer 137cs technique
Canadian Journal of Fisheries and Aquatic Sciences, 2000Co-Authors: Graham D Sherwood, Julie C Brodeur, Joseph B Rasmussen, David J Rowan, Alice HontelaAbstract:While the flow of energy is understood to determine the growth of organisms and the productivity of ecosystems, little is known about the sublethal effect of pollutants on the energetic efficiency of wild populations. We used field estimates of fish growth coupled to in situ estimates of food consumption rates obtained from the mass balance of a globally dispersed, trophically transferred radiotracer (137Cs) to demonstrate the bioenergetic impairment of yellow Perch (Perca flavescens) from lakes polluted by heavy metals (Cd, Cu, and Zn). Annual growth increment relative to the total energy budget (conversion efficiency) was about three times lower in cortisol-impaired yellow Perch from metal-polluted lakes relative to yellow Perch from reference lakes (4.2% compared with 10.8%), suggesting that fish exposed to pollutants experienced greater total energetic costs. In addition, metal-polluted lakes were dominated by adult yellow Perch populations and simplified prey bases, suggesting that effects are occurr...
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impaired cortisol secretion in yellow Perch perca flavescens from lakes contaminated by heavy metals in vivo and in vitro assessment
Canadian Journal of Fisheries and Aquatic Sciences, 1997Co-Authors: Julie C Brodeur, Graham D Sherwood, Joseph B Rasmussen, Alice HontelaAbstract:The characteristic elevation of plasma cortisol levels in response to an acute stress of capture was impaired in both male and female yellow Perch (Perca flavescens) from lakes contaminated by heav...
James W Rajotte - One of the best experts on this subject based on the ideXlab platform.
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effects of environmental metal contamination on the condition swimming performance and tissue metabolic capacities of wild yellow Perch perca flavescens
Canadian Journal of Fisheries and Aquatic Sciences, 2002Co-Authors: James W Rajotte, Patrice CoutureAbstract:In this study, the general condition, swimming capacities, and tissue metabolic capacities and metal concentrations in wild yellow Perch (Perca flavescens) were examined from a range of metal-conta...
David O. Evans - One of the best experts on this subject based on the ideXlab platform.
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Behaviour, Energetics, and Associated Mortality of Young-of-the-Year White Perch (Morone americana) and Yellow Perch (Perca flavescens) under Simulated Winter Conditions
Canadian Journal of Fisheries and Aquatic Sciences, 1991Co-Authors: Timothy B. Johnson, David O. EvansAbstract:After 150 d of simulated winter conditions, 71.2% of the white Perch (Morone americana) had died at 2.5 °C, while only 11.1% had died at 4.0 °C. For yellow Perch (Perca flavescens), 0.8% had died at 2.5 °C, while 17.7% had died at 4.0 °C. For both species, small fish died first. Multiple regression models relating overwinter mortality versus fall total length and winter duration predict 3.3 times greater mortality for white Perch versus similar sized yellow Perch at winter temperature regimes typical of the Great Lakes region. In laboratory tanks, white Perch remained active throughout the winter period, while yellow Perch sought cover and rested on or near the bottom of the experimental tanks. As a direct consequence, yellow Perch had a lower routine metabolic rate and consumed body energy more gradually than white Perch. During their inactive wintering period at 4.0 °C, yellow Perch consumed 25.8% less oxygen than white Perch. Actual measurements of dry weight loss indicated that yellow Perch in the exp...
F. Joseph Margraf - One of the best experts on this subject based on the ideXlab platform.
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Spatial and Temporal Patterns of Food Use by White Perch and Yellow Perch in Lake Erie
Journal of Freshwater Ecology, 1994Co-Authors: Donna L. Parrish, F. Joseph MargrafAbstract:ABSTRACT We determined spatial and temporal feeding patterns of white Perch (Morone americana) and yellow Perch (Perca flavescens) in Lake Erie by analysis of stomach contents. Diets were compared across years (1983–1985), seasons, basins of the lake (western and central), and depth in the western basin. Diets of these two fish species were generally similar, although white Perch tended to use more zooplankton, while yellow Perch consumed more Chironomidae, Sphaeriidae, and fishes. In other instances, competition apparently led to resource partitioning that resulted from differences in ontogenetic feeding requirements and mouth position between white Perch and yellow Perch.
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Growth responses of age 0 white Perch and yellow Perch from field-enclosure experiments
Hydrobiologia, 1993Co-Authors: Donna L. Parrish, F. Joseph MargrafAbstract:In this paper, we investigate the potential for competition between age 0 white Perch Morone americana and yellow Perch Perca flavescens in field-enclosure experiments. In 1986 and 1987, different densities of white Perch and yellow Perch were stocked into cages in the western basin of Lake Erie and their growth responses determined. Fish were weighed and measured pre- and post-stocking. In 1986 when fish were food-limited, individual growth of both species were negatively affected by increased total fish density; yellow Perch to a greater extent. In 1987, experiments were carried out later in the year at lower temperatures. Yellow Perch were shown to feed and continue to grow at lower water temperatures than white Perch. We conclude that competition in summer may be mitigated in the fall because of differences in thermal optima between these two species.