Resource partitioning between brook trout (Salvelinus fontinalis Mitchill) and creek chub (Semotilus atromaculatus Mitchill) in selected oligotrophic lakes of southern Quebec

1982 ◽  
Vol 60 (7) ◽  
pp. 1612-1617 ◽  
Author(s):  
Pierre Magnan ◽  
Gérard J. FitzGerald
Keyword(s):  
Spatial Distribution ◽  
Resource Partitioning ◽  
Brook Trout ◽  
Food Habits ◽  
Salvelinus Fontinalis ◽  
Niche Shift ◽  
Sympatric Populations ◽  
Semotilus Atromaculatus ◽  
Trout Population ◽  
Creek Chub

The spatial distribution, food habits, and growth of an allopatric brook trout (Salvelinus fontinalis) population was compared with a trout population coexisting with creek chub (Semotilus atromaculatus). Sympatric trout differed in spatial distribution and food habits from allopatric trout suggesting a niche shift of the trout when they live with creek chub. Also, although there is a certain overlap in diet and spatial distribution, sympatric populations of the two species differed on these resource axes. However, growth of sympatric trout is not clearly related to the presence or absence of the creek chub, suggesting that factors other than interspecific competiton may affect growth in the seven study lakes.

Mechanisms responsible for the niche shift of brook charr, Salvelinus fontinalis Mitchill, when living sympatrically with creek chub, Semotilus atromaculatus Mitchill

1984 ◽  
Vol 62 (8) ◽  
pp. 1548-1555 ◽  
Author(s):  
Pierre Magnan ◽  
Gérard J. FitzGerald
Keyword(s):  
Laboratory Experiments ◽  
Salvelinus Fontinalis ◽  
Niche Shift ◽  
Intraspecific Aggression ◽  
Brook Charr ◽  
Semotilus Atromaculatus ◽  
High Level ◽  
Gill Raker ◽  
Creek Chub ◽  
Study Laboratory

When brook charr, Salvelinus fontinalis Mitchill, are in allopatry in oligotrophic Québec lakes, they feed largely on macrobenthic invertebrates. However, when brook charr cooccur with creek chub, Semotilus atromaculatus Mitchill, they feed largely on zooplankton. In the present study, laboratory experiments showed that creek chub were more effective than brook charr in searching for hidden, patchily distributed prey. The searching efficiency of an individual chub feeding in a group was improved through social facilitation. In contrast, the high level of intraspecific aggression observed in brook charr prevents the formation of such feeding groups. In the laboratory, brook charr were able to displace creek chub from the food source because of interspecific aggression. Data are presented showing that chub are morphologically better adapted than charr to feed on benthos (subterminal orientation of the mouth and protrusible premaxillae), while the charr are better adapted than chub to feed on zooplankton (gill raker structure). Differences in feeding behaviour, morphology, and relative abundance between these species appear to be important in the observed niche shift of brook charr in nature.

Some Factors Regulating Piscivory of Brook Trout, Salvelinus fontinalis, in Lakes of the Laurentian Shield

1991 ◽  
Vol 48 (9) ◽  
pp. 1735-1743 ◽  
Author(s):  
Pierre East ◽  
Pierre Magnan
Keyword(s):  
Brook Trout ◽  
Laboratory Experiments ◽  
Salvelinus Fontinalis ◽  
The Other ◽  
Prey Fish ◽  
Significant Preference ◽  
Prey Refuge ◽  
Semotilus Atromaculatus ◽  
Foraging Pattern ◽  
Creek Chub

A survey of 13 lakes containing brook trout, Salvelinus fontinalis, and northern redbelly dace, Phoxinus eos, five lakes containing trout and creek chub, Semotilus atromaculatus, and six lakes containing trout, dace, and chub indicated that prey-fish could represent up to 30% of trout diet by weight. We observed that trout preyed almost exclusively on dace, predation increased with trout size, predation on dace was significantly higher in the Salvelinus-Phoxinus-Semotilus association than in the Salvelinus-Phoxinus association even though trout were significantly smaller in the former than in the latter association, and predation in the Salvelinus-Phoxinus-Semotilus association was higher in two lakes and nearly always absent in the other four. Laboratory experiments indicated that small trout (150–250 mm total length (TL)) preferred small prey-fish (40–60 mm TL), large trout (250–380 mm TL) showed no significant preference with regard to the size of prey-fish (up to 170 mm TL), trout of both size classes preferred dace when dace and chub were present, presence of refuge (Cassandra calyculata) for prey-fish significantly reduced the number of attacks and captures upon dace, and large trout switched from an active to a sit-and-wait foraging pattern when a prey refuge was present.

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.

Experimental Plantings of Brook Trout (Salvelinus fontinalis) from Furunculosis-Infected Stock

1968 ◽  
Vol 25 (12) ◽  
pp. 2643-2649 ◽  
Author(s):  
L. A. McDermott ◽  
A. H. Berst
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Infected Fish ◽  
Aeromonas Salmonicida ◽  
Control Fish ◽  
Southern Ontario ◽  
Trout Population ◽  
Hatchery Stock ◽  
Associated Species ◽  
Made In

Preliminary sampling revealed the presence of furunculosis disease in the resident brook trout population of the southern Ontario trout stream used in this study.Two plantings of marked yearling brook trout were made in the study area in 1966; one in the spring, and the other in the fall. The spring planting consisted of 1000 brook trout with a predetermined incidence of furunculosis infection and an equal number of trout with no evidence of infection. The fall planting consisted of 2000 brook trout with a known incidence of furunculosis infection.The stream was electrofished periodically during the 2-year period after the first planting. A total of 445 brook trout (140 of the planted hatchery stock, and 305 resident trout) and 127 fish of associated species were captured and examined for the presence of Aeromonas salmonicida, causative agent of furunculosis.Recovery rates of the "infected" and "noninfected" stocks of brook trout were similar, and there was no evidence of transmission of A. salmonicida from the infected fish to the control fish, nor the resident population of brook trout and other species of fish captured.

scholarly journals Brook trout (Salvelinus fontinalis) extinction in small boreal lakes revealed by ephippia pigmentation: a preliminary analysis

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Alexandre Bérubé Tellier ◽  
Paul E. Drevnick ◽  
Andrea Bertolo
Keyword(s):  
Brook Trout ◽  
Fish Assemblages ◽  
Salvelinus Fontinalis ◽  
Sediment Cores ◽  
Experimental Studies ◽  
Cost Effective ◽  
Fish Predation ◽  
Boreal Lakes ◽  
Predation Pressure ◽  
Trout Population

<p>Ephippium pigmentation is a plastic trait which can be related to a trade-off between visual predation pressure and better protection of cladoceran eggs against different types of stress. Experimental studies showed that planktivorous fish exert a greater predation pressure on individuals carrying darker ephippia, but little is known about the variation of ephippium pigmentation along gradients of fish predation pressure in natural conditions. For this study, our experimental design included four small boreal lakes with known fish assemblages. Two of the lakes have viable brook trout (<em>Salvelinus fontinalis</em>) populations, whereas the other two lakes experienced brook trout extinctions during the 20<sup>th</sup> century. Cladoceran ephippia were extracted from sediment cores at layers corresponding to the documented post- extinction phase (1990's) and from an older layer (1950's) for which the brook trout population status is not known precisely. Our first objective was to determine whether brook trout extinction has a direct effect on both ephippium pigmentation and size. Our second objective was to give a preliminary assessment of the status of brook trout populations in the 1950's by comparing the variation in ephippia traits measured from this layer to those measured in the 1990's, for which the extinction patterns are well known. Cost-effective image analysis was used to assess variation in pigmentation levels in ephippia. This approach provided a proxy for the amount of melanin invested in each ephippium analysed. Our study clearly shows that ephippium pigmentation may represent a better indicator of the presence of fish predators than ephippium size, a trait that showed a less clear pattern of variation between lakes with and without fish. For the 1990's period, ephippia from fishless lakes were darker and showed a slight tendency to be larger than ephippia from lakes with brook trout. However, no clear differences in either ephippium size or pigmentation were observed between the 1990's and 1950's layers within each lake. This suggests that brook trout extinction already occurred before the 1950’s, or that brook trout population abundance was already extremely low before and after the 1990’s. Our preliminary study shows that ephippium pigmentation can be used as a tool to quickly assess present and past predation levels on zooplankton when only sediment samples are available.</p>

Trout Production and Eels in Bill Lake, Saguenay County, Quebec

1973 ◽  
Vol 30 (9) ◽  
pp. 1398-1401 ◽  
Author(s):  
J. F. O’Connor ◽  
G. Power
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Annual Production ◽  
Anguilla Rostrata ◽  
Apparent Position ◽  
Trout Population ◽  
American Eels

Competition and predation by American eels (Anguilla rostrata) is believed to have substantially reduced trout population and production in Bill Lake. Brook trout (Salvelinus fontinalis) occurred at densities of 7/ha; biomass of 0.34 kg/ha and annual production was estimated at 0.21 kg/ha. This is considerably less than values for trout density, biomass, and production in other lakes in the Matamek watershed from which eels appear to be absent. Eels in Bill Lake are old and large but not numerous, in keeping with their apparent position as top carnivores.

Comparative Ecology and Behavior of Domestic, Hybrid, and Wild Strains of Brook Trout, Salvelinus fontinalis, after Stocking

1990 ◽  
Vol 47 (12) ◽  
pp. 2285-2292 ◽  
Author(s):  
Stephanie Lachance ◽  
Pierre Magnan
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Niche Shift ◽  
Feeding Niche ◽  
Spatially Distributed ◽  
Wild Strains ◽  
Males And Females ◽  
Almost All ◽  
And Behavior ◽  
Sexually Mature

Two years after planting in six small oligotrophic lakes, domestic, hybrid and wild strains of brook trout, Salvelinus fontinalis, used space and food resources in the same way as native trout. Although trout living with or without white sucker, Catostomus commersoni, were similarly spatially distributed, they had different diets, suggesting a feeding niche shift of trout in the presence of sucker; we concluded that this shift is under phenotypic control because each planted strain came from similar genetic backgrounds. Sexual maturity was related to the size of individuals, regardless of the strain, and males matured before females. Almost all males and females were sexually mature in the first fall after stocking except wild females (3.0 and 75% matured during the first and second fall, respectively). Gonadosomatic indices (GSI) of domestic and hybrid females were similar during the first fall, but the GSI of domestic females was significantly higher than that of hybrid and wild strains in the second fail. Mean egg diameters were similar among the three strains during the two falls, but fecundity of domestic females, after correction for size differences, was significantly higher than that of hybrid females which, in turn, was significantly higher than that of wild ones.

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