Biotic and Abiotic Determinants of the Diet of Brook Trout, Salvelinus fontinalis, in Lakes of the Laurentian Shield

From a survey of 12 lakes containing brook trout, Salvelinus fontinalis, 12 lakes containing brook trout and creek chub, Semotilus atromaculatus, and 13 lakes containing brook trout and white sucker, Catostomus commersoni, we built seven multiple linear regression models to account for the mean percent weight of different prey categories in the diet of brook trout. Presence of chub and sucker, zooplankton community structure, sampling date, morphoedaphic index, and the importance of rock outcrops accounted for 88% of the variation in weight of zoobenthos eaten by trout, which was the preferred prey in allopatry. Thirty percent of the variation in weight of zooplankton eaten by trout was explained by the importance of macrophytes and other refuges for fish. Models for amphipods, dipteran pupae, swimming insects, terrestrial insects, and prey-fish explained between 36 and 63% of the variation. The presence of white sucker or an index of their impact (mean length or density of Cladocera) and the characteristics of littoral habitats appeared in six of seven models. Littorasl habitats seemed particularly determinant for the inclusion of prey-fish in the diet, more prey-fish being eaten when regufes were abundant. Variables related to lake morphometry and physicochemistry appeared less regularly in the models.

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Interactions between Brook Charr, Salvelinus fontinalis, and Nonsalmonid Species: Ecological Shift, Morphological Shift, and Their Impact on Zooplankton Communities

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f88-123 ◽

1988 ◽

Vol 45 (6) ◽

pp. 999-1009 ◽

Cited By ~ 62

Author(s):

Pierre Magnan

Keyword(s):

Salvelinus Fontinalis ◽

Zooplankton Community ◽

Niche Shift ◽

White Sucker ◽

Brook Charr ◽

Gill Rakers ◽

Zooplankton Community Structure ◽

The Mean ◽

Zooplankton Communities ◽

Creek Chub

A quantitative survey of 26 oligotrophic Quebec lakes indicated that the presence of creek chub (Semotilus atromaculatus) or white sucker (Catostomus commersoni) had an impact on brook charr (Salvelinus fontinalis) populations. Evidence for competitive interactions among these species was provided by the observation that (1) the mean annual yield (kilograms per hectare) of charr was significantly reduced when they lived sympatrically with these species, (2) charr shifted their food habits from benthic organisms to Zooplankton in the presence of creek chub and (or) white sucker, and (3) the length of the gill rakers of charr was significantly higher in lakes containing chubs and suckers. As the length of the gill rakers is reported to be correlated with the extent of plankton feeding, this latter result was interpreted as a morphological change associated with increased exploitation of Zooplankton in sympatry. When occurring with creek chub, the niche shift of brook charr resulted in a significant change in Zooplankton community structure. The proportion of large Zooplankton organisms (>1.1 mm) declined whereas that of the smaller ones (<0.6 mm) increased. Also, the mean length of Holopedium, the larger cladocerans, was significantly reduced in sympatric creek chub–charr lakes compared with lakes where charr lived allopatrically. A similar impact on Zooplankton was not as clear when charr occurred with white sucker. When living with white sucker, brook charr populations appeared to be sufficiently reduced as to have little or no effect on Zooplankton communities.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f90-253 ◽

1990 ◽

Vol 47 (12) ◽

pp. 2278-2284 ◽

Cited By ~ 46

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.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f91-205 ◽

1991 ◽

Vol 48 (9) ◽

pp. 1735-1743 ◽

Cited By ~ 25

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.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f91-102 ◽

1991 ◽

Vol 48 (5) ◽

pp. 857-867 ◽

Cited By ~ 47

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.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f01-137 ◽

2001 ◽

Vol 58 (10) ◽

pp. 1998-2010 ◽

Cited By ~ 8

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·ha1 to 31.3 kg·ha1 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.

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

Canadian Journal of Zoology ◽

10.1139/z96-146 ◽

1996 ◽

Vol 74 (7) ◽

pp. 1304-1312 ◽

Cited By ~ 14

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.

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