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Louis Bernatchez - One of the best experts on this subject based on the ideXlab platform.
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Speciation Reversal in European Whitefish (Coregonus lavaretus (L.)) Caused by Competitor Invasion
2016Co-Authors: Shripathi Bhat, Per-arne Amundsen, Karl Øystein Gjell, Svein-erik Fevolden, Louis BernatchezAbstract:Invasion of exotic species has caused the loss of biodiversity and imparts evolutionary and ecological changes in the introduced systems. In northern Fennoscandia, European whitefish (Coregonus lavaretus (L.)) is a highly polymorphic species displaying adaptive radiations into partially reproductively isolated and thus genetically differentiated sympatric morphs utilizing the planktivorous and benthivorous food niche in many lakes. In 1993, Lake Skrukkebukta was invaded by vendace (Coregonus albula (L.)) which is a zooplanktivorous specialist. The vendace displaced the densely rakered whitefish from its preferred pelagic niche to the benthic habitat harbouring the large sparsely rakered whitefish. In this study, we investigate the potential influence of the vendace invasion on the breakdown of reproductive isolation between the two whitefish morphs. We inferred the genotypic and phenotypic differentiation between the two morphs collected at the arrival (1993) and 15 years after (2008) the vendace invasion using 16 microsatellite loci and gill raker numbers, the most distinctive adaptive phenotypic trait between them. The comparison of gill raker number distributions revealed two modes growing closer over 15 years following the invasion. Bayesian analyses of genotypes revealed that the two genetically distinct whitefish morphs that existed in 1993 had collapsed into a single population in 2008. The decline in association between the gill raker numbers and admixture values over 15 years corroborates the findings from the Bayesian analysis. Our study thus suggests an apparent decrease of reproductive isolation in a morph-pair of European whitefish within 15 years (.
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Unrooted ML phylogram based on the cytochromes data set.
2012Co-Authors: Alexis Crête-lafrenière, Laura K. Weir, Louis BernatchezAbstract:A: Nodes with bootstrap values less than 75% are indicated with open circles (n = 29). For some deep nodes, ML bootstrap support/BAY posterior probabilities/MP bootstrap supports are shown above the node. B: Radial view of the same tree. Abbreviations: B = Brachymystax, C = Coregonus, H = Hucho, O = Oncorhynchus, Pa = Parahucho perryi, P = Prosopium, Sm = Salmo, Sv = Salvelinus, Svth = Salvethymus svetovidovi, St = Stenodus leucichthys and T = Thymallus. Numbers beside each sample correspond to identification numbers in Table S1.
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reduced sperm performance in backcross hybrids between species pairs of whitefish Coregonus clupeaformis
Canadian Journal of Zoology, 2009Co-Authors: Louis Bernatchez, Nicolas Derome, Andrew R Whiteley, K N Persaud, Robert MontgomerieAbstract:Previous work has demonstrated that genomic incompatibilities work together with ecologically divergent selec- tion to promote and maintain reproductive isolation between incipient species (dwarf and normal) of lake whitefish (Core- gonus clupeaformis (Mitchill, 1818)). Whitefish spawn in groups with external fertilization, which creates conditions for strong sperm competition. In this study, we asked whether reduced sperm performance in hybrids from whitefish species- pair matings might contribute to postzygotic isolating mechanisms between these taxa. We examined two sperm traits, sperm swimming speed and flagellum length, in pure dwarf and normal whitefish and in their F1 and backcross hybrids. We observed significantly reduced sperm swimming speed in backcross but not in F1 hybrids. Sperm flagellum length was not significantly correlated with sperm swimming speed. These results demonstrate that F1 hybrids formed in nature should be capable of the same fertilization success as the parental species during sperm competition, everything else being equal. However, reduced sperm performance in the backcross generation is consistent with other evidence suggesting that genomic incompatibilities create a range of negative fitness effects in post-F1 whitefish hybrids and provides evidence for an additional postzygotic isolation mechanism involved in the incipient speciation of sympatric dwarf and normal white- fish. Resume´ : Des travaux anterieurs ont demontreque les incompatibilitesg enetiques agissent de concert avec la selection di- vergente en fonction de l'ecologie pour favoriser et maintenir l'isolement genetique entre les especes en emergence (naines et normales) chez les grands coregones (Coregonus clupeaformis (Mitchill, 1818)). Les coregones fraient en groupes et ont une fecondation externe, ce qui cree des conditions de forte competition spermatique. Dans notre etude, nous cherchons a savoir si la performance reduite des spermatozoo¨des des hybrides provenant de l'accouplement de paires d'especes de core ´- gones peut contribuer aux mecanismes d'isolement post-zygotique entre ces taxons. Nous examinons deux caracteristiques des spermatozoo¨des, la vitesse de nage et la longueur du flagelle des spermatozoo¨des, chez des coregones nains et normaux purs et leurs hybrides de F1 et de retrocroisement. Il y a une reduction significative de la vitesse de nage des spermato- zoo¨des chez les hybrides de retrocroisement, mais non ceux de F1. Il n'existe pas de correlation significative entre la lon- gueur du flagelle et la vitesse de nage des spermatozoo¨des. Ces resultats demontrent que les hybrides de F1 formese n nature devraient pouvoir obtenir le meme succesd e fecondation que les especes parentales durant la competition sperma- tique, toutes autres choses etant egales. Cependant, la performance reduite des spermatozoo¨des de la generation de retro- croisement est compatible avec d'autres indications qui laissent croire que les incompatibilitesg enetiques creent une gamme d'effets negatifs de fitness chez les hybrides post F1 de coregones; elle fournit aussi des preuves de l'implication d'un mecanisme additionnel d'isolement post-zygotique dans la speciation en emergence des coregones sympatriques nains et normaux. (Traduit par la Redaction)
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candidate genes and adaptive radiation insights from transcriptional adaptation to the limnetic niche among coregonine fishes Coregonus spp salmonidae
Molecular Biology and Evolution, 2008Co-Authors: Julie Jeukens, David Bittner, Rune Knudsen, Louis BernatchezAbstract:In the past 40 years, there has been increasing acceptance that variation in levels of gene expression represents a major source of evolutionary novelty. Gene expression divergence is therefore likely to be involved in the emergence of incipient species, namely, in a context of adaptive radiation. In the lake whitefish species complex (Coregonus clupeaformis), previous microarray experiments have led to the identification of candidate genes potentially implicated in the parallel evolution of the limnetic dwarf lake whitefish, which is highly distinct from the benthic normal lake whitefish in life history, morphology, metabolism, and behavior, and yet diverged from it only approximately 15,000 years before present. The aim of the present study was to address transcriptional divergence for six candidate genes among lake whitefish and European whitefish (Coregonus lavaretus) species pairs, as well as lake cisco (Coregonus artedi) and vendace (Coregonus albula). The main goal was to test the hypothesis that parallel phenotypic adaptation toward the use of the limnetic niche in coregonine fishes is accompanied by parallelism in candidate gene transcription as measured by quantitative real-time polymerase chain reaction. Results obtained for three candidate genes, whereby parallelism in expression was observed across all whitefish species pairs, provide strong support for the hypothesis that divergent natural selection plays an important role in the adaptive radiation of whitefish species. However, this parallelism in expression did not extend to cisco and vendace, thereby infirming transcriptional convergence between limnetic whitefish species and their limnetic congeners for these genes. As recently proposed (Lynch 2007a. The evolution of genetic networks by non-adaptive processes. Nat Rev Genet. 8:803-813), these results may suggest that convergent phenotypic evolution can result from nonadaptive shaping of genome architecture in independently evolved coregonine lineages.
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the transcriptomics of ecological convergence between 2 limnetic coregonine fishes salmonidae
Molecular Biology and Evolution, 2006Co-Authors: Nicolas Derome, Louis BernatchezAbstract:Species living in comparable habitats often display strikingly similar patterns of specialization, suggesting that natural selection can lead to predictable evolutionary changes. Elucidating the genomic basis underlying such adaptive phenotypic changes is a major goal in evolutionary biology. Increasing evidence indicates that natural selection would first modulate gene regulation during the process of population divergence. Previously, we showed that parallel phenotypic adaptations of the dwarf whitefish (Coregonus clupeaformis) ecotype to the limnetic trophic niche involved parallel transcriptional changes at the same genes involved in muscle contraction and energetic metabolism relative to the sympatric normal ecotype. Here, we tested whether the same genes are also implicated in a limnetic specialist species, the cisco (Coregonus artedi), which is the most likely competitor of dwarf whitefish. Significant upregulation was detected in cisco at the same 6 candidate genes functionally involved in modulating swimming activity, namely 5 variants of a major protein of fast muscle and 1 putative catalytic crystallin enzyme. Moreover, 3 of 5 variants and the same putative catalytic crystallin enzyme were upregulated in cisco relative to the dwarf ecotype, indicating a greater physiological potential of the former for exploiting the limnetic trophic niche. This study provides the first empirical evidence that recent, parallel phenotypic evolution toward the use of the same ecological niche occupied by a specialist competitor involved similar adaptive changes in expression at the same genes. As such, this study provides strong support to the general hypothesis that directional selection acting on gene regulation may promote rapid phenotypic divergence and ultimately speciation.
Per-arne Amundsen - One of the best experts on this subject based on the ideXlab platform.
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composition and body size in two zooplankton communities of the Pasvik River System, northern Norway
2016Co-Authors: Thomas Bhn, Per-arne AmundsenAbstract:]To whom correspondence should be addressed Abstract Species composition and body-size distribution were studied in the crustacean zooplankton communities of two limnologically similar lake localities situated 50 km apart in the Pasvik River System, northern Norway. A recent invasion and successive downstream expansion of vendace (Coregonus albula), a specialized zooplanktivorous fish, allowed comparisons between sites with different predation pressures. Vendace had established a high population density and was the dominant fish species in the pelagic of the upper locality, but had just invaded the lower locality with a small number of individuals. Whitefish (Coregonus lavaretus), a closely related but less specialized zooplanktivore species, dominated the native fish community of both lakes. The zooplankton community of the upper locality was dominated in June and August by Bosmina longirostris, the smallest zooplankton species represented in the water course, and in September by Daphnia cristata. The lower locality was dominated by the larger Holopedium gibberum and Eudiaptomus graciloide
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Speciation Reversal in European Whitefish (Coregonus lavaretus (L.)) Caused by Competitor Invasion
2016Co-Authors: Shripathi Bhat, Per-arne Amundsen, Karl Øystein Gjell, Svein-erik Fevolden, Louis BernatchezAbstract:Invasion of exotic species has caused the loss of biodiversity and imparts evolutionary and ecological changes in the introduced systems. In northern Fennoscandia, European whitefish (Coregonus lavaretus (L.)) is a highly polymorphic species displaying adaptive radiations into partially reproductively isolated and thus genetically differentiated sympatric morphs utilizing the planktivorous and benthivorous food niche in many lakes. In 1993, Lake Skrukkebukta was invaded by vendace (Coregonus albula (L.)) which is a zooplanktivorous specialist. The vendace displaced the densely rakered whitefish from its preferred pelagic niche to the benthic habitat harbouring the large sparsely rakered whitefish. In this study, we investigate the potential influence of the vendace invasion on the breakdown of reproductive isolation between the two whitefish morphs. We inferred the genotypic and phenotypic differentiation between the two morphs collected at the arrival (1993) and 15 years after (2008) the vendace invasion using 16 microsatellite loci and gill raker numbers, the most distinctive adaptive phenotypic trait between them. The comparison of gill raker number distributions revealed two modes growing closer over 15 years following the invasion. Bayesian analyses of genotypes revealed that the two genetically distinct whitefish morphs that existed in 1993 had collapsed into a single population in 2008. The decline in association between the gill raker numbers and admixture values over 15 years corroborates the findings from the Bayesian analysis. Our study thus suggests an apparent decrease of reproductive isolation in a morph-pair of European whitefish within 15 years (.
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thermal habitat segregation among morphotypes of whitefish Coregonus lavaretus salmonidae and invasive vendace c albula a mechanism for co existence
Freshwater Biology, 2015Co-Authors: Brianne Kelly, Per-arne Amundsen, Michael PowerAbstract:Summary Aquatic invasive species can have a variety of negative impacts on the ecosystems they invade. Carbon and nitrogen stable isotopes in the muscle tissue of aquatic organisms have proved useful for evaluating post-invasion dietary shifts among species. However, oxygen and carbon stable isotopes in fish otoliths have the potential to provide additional data on thermal habitat, diet and metabolism, when investigating interactions among sympatric native and invasive fishes. We conducted oxygen and carbon stable isotope analysis on the otoliths of three morphotypes of native whitefish (Coregonus lavaretus) and invasive vendace (Coregonus albula) at two sites within the sub-Arctic Pasvik watercourse in northern Norway. Mean temperature use among morphotypes and species over the course of the growing season ranged from 7.5 °C to 11.2 °C. Otolith δ13C was significantly positively correlated to fish muscle tissue δ13C (P < 0.05, r2 = 0.53). Significant differences in temperature use and δ13C among morphotypes and between species were found in the downstream site but not the upstream site. Complementary partitioning of thermal and dietary resource use in the downstream site coincides with a higher abundance of whitefish, enabling the coexistence of both species. In contrast, vendace were dominant in the upstream site where no differentiation in resource use among morphotypes and between species was evident. This study demonstrates the usefulness of stable oxygen and carbon otolith isotopes for characterising resource use and highlights the importance of investigating thermal habitat use as a factor influencing the success of invasive fishes.
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Invasion of vendace Coregonus albula in a subarctic watercourse
Biological Conservation, 1999Co-Authors: Per-arne Amundsen, Odd Terje Sandlund, Yuri S. Reshetnikov, Frode J. Staldvik, Nikolai A. Kashulin, Anatoly A. Lukin, Thomas Bøhn, Olga PopovaAbstract:Abstract Vendace Coregonus albula have recently invaded the Pasvik River system, a subarctic watercourse on the borderline between Norway and Russia, after having been introduced into the Finnish headwaters in the 1950–1960s. The watercourse is characterised by several consecutive lakes and reservoirs. Vendace were first recorded in the upper part in 1989, and had by 1995 invaded the whole 120 km long water system. In the upper part, vendace have become the dominant fish species in the pelagic zone, whereas whitefish Coregonus lavaretus have been relegated to the profundal and littoral zones. In the lower part, whitefish were by 1995 still dominant in the pelagic habitat, but vendace constituted 30% of the pelagic catches after being first recorded there in 1993. Vendace have established reproducing populations in the whole watercourse, with the 1990 and 1991 year-classes being particularly strong and important for the downward displacement. The new occurrence of vendace in the Pasvik River system probably represents the world's northernmost distribution of the species. The invasion appears to have a major ecological impact on the native communities, and represents a threat for both biodiversity conservation and the commercial fishery in the watercourse.
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effects of invading vendace Coregonus albula l on species composition and body size in two zooplankton communities of the pasvik river system northern norway
Journal of Plankton Research, 1998Co-Authors: Thomas Bøhn, Per-arne AmundsenAbstract:Species composition and body-size distribution were studied in the crustacean zooplankton communities of two limnologically similar lake localities situated 50 km apart in the Pasvik River System, northern Norway. A recent invasion and successive downstream expansion of vendace (Coregonus albula), a specialized zooplanktivorous fish, allowed comparisons between sites with different predation pressures. Vendace had established a high population density and was the dominant fish species in the pelagic of the upper locality, but had just invaded the lower locality with a small number of individuals. Whitefish (Coregonus lavaretus), a closely related but less specialized zooplanktivore species, dominated the native fish community of both lakes. The zooplankton community of the upper locality was dominated in June and August by Bosmina longirostris, the smallest zooplankton species represented in the water course, and in September by Daphnia cristata. The lower locality was dominated by the larger Holopedium gibberum and Eudiaptomus graciloides in June, by D.cristata in August, and by D.cristata and B.longirostris in September. The mean body size of the three most abundant cladoceran species was significantly smaller in the upper locality, compared to the lower locality. It was concluded that the invasion and establishment of a dense vendace population in the upper locality had increased the predation pressure in the pelagic, resulting in a reduction of body size and a shift towards smaller species in the zooplankton community.
Patrick C Brunner - One of the best experts on this subject based on the ideXlab platform.
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evolutionary homoplasy among species flocks of central alpine Coregonus teleostei salmoniformes
Copeia, 2005Co-Authors: Marlis R Douglas, Patrick C Brunner, Michael E DouglasAbstract:Evolution of phenotype and mode of speciation were examined for 19 Coregonus populations within and among eight lakes in the Central Alpine region of Europe. These populations reflect a mosaic of morphological, ecological, and life history traits, and thus represent numerous forms (qualitatively described according to relative body size and ecology). Each population had been previously evaluated for six microsatellite DNA loci, and herein for five meristic counts, four fin pigmentation characters, three body color variables, three measures relating to spawning ecology, an estimate of breeding tubercles, and average weight (= size). The two matrices (genotype vs. phenotype/ecology) were then tested for significance amongst themselves, and against evolutionary and geographic models. Microsatellite data associated significantly with a species flock model in which in situ diversification occurred from a common ancestor in each lake or cluster of neighboring lakes. However, phenotype/ecology associated significantly with a model invoking multiple invasions of lakes by pre-existing forms. The latter supports historic perspectives on the evolution of Central Alpine Coregonus and suggests forms within lakes have adapted to specific within-lake environmental niches that are replicated across lakes. This convergence of form and function has long clouded an understanding of coregonine biodiversity, and we suggest it represents a homoplasious condition (i.e., a similarity due not to genealogy but to iteration). This compendium of homoplasious and homologous characters is actually quite unique in nature, and the evolutionary diversification of Central Alpine Coregonus can now be evaluated according to the relative contribution of each character type.
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biodiversity of central alpine Coregonus salmoniformes impact of one hundred years of management
Ecological Applications, 2002Co-Authors: Marlis R Douglas, Patrick C BrunnerAbstract:Coregonus has been under intense management in the Central Alpine region of Europe for more than 100 yr. To assess how this management has affected local populations, extant patterns of genotypic and phenotypic diversity were examined within a taxonomic frame- work to identify indigenous and introduced populations, and to provide a perspective on future management based on true conservation units. Thirty-three Coregonus populations from 17 selected Central Alpine lakes were classified as indigenous, introduced, or uncertain (i.e., status or origin unknown). Using genetic data across six microsatellite DNA loci, individuals of the 19 indigenous populations could be correctly allocated to population with 71% probability in a nonparametric discriminant analysis. The same individuals could be allocated to population with 69% probability using five meristic counts, and but 44% probability using four fin- pigmentation characteristics. Discriminating ability was enhanced to 91% when both meristic and color data were coalesced, and composite use of genetic and phenotypic data provided an average discrimination probability of 79%. Capabilities of the various data sets decreased when applied separately to allocate specimens according to either lake (n = 8) or lake-aggregate (n = 5). Genetic data were then statistically contrasted against four taxonomic hierarchies: Kot- telatt's species arrangement, and Steinmann's depiction of "ecotype," "natio," and a combi- nation of the two. Genetic data were statistically congruent with Kottelat's depiction of species, and with Steinmann's arrangement of populations into natio (or regions). Results support ar- guments that indigenous populations of Central Alpine Coregonus are distinct, with closest relations within lakes (or lake aggregates). Their evolutionary origin is best described using a species-flock model. Genetic data for 19 indigenous populations were combined with those for 14 populations either introduced or of unknown provenance. Pairwise comparisons of allele and genotype frequencies demonstrated significant genetic differences among populations, sup- porting uniqueness of rare forms, such as "alpenrheinfelchen" of Lake Konstanz or "winter- brienzlig" of Lake Brienz, but also revealed genetic divergence of introduced populations from their alleged source. Introduced populations clustered within the group containing their pop- ulation of origin but did not associate directly with their source, thus indicating post-introduction genetic divergence. These findings were most remarkable for "balchen" of Lake Ageri and "palee" from Lake Geneve (stocked from lakes Zug and Geneve, respectively). Also, "sem- pacherbalchen" of Lake Sempach was significantly distinct from all other populations, even though it was supposedly stocked "from every lake and into every lake." It also clustered with populations in geographic proximity, suggesting that it may still retain historic endemicity. Finally, "lavarello" and "nuova forma" from Lake Maggiore did not group as expected with forms from Lake Konstanz or lakes Neuchatel/Bienne, but instead with those from Lake Zug. Nonparametric discriminant analyses over 32 populations, again employing genotypic and phenotypic data, confirmed divergence of introduced populations and clarified status for pop- ulations of uncertain origin. Results of analyses also confirmed that historic signatures still persist in extant populations. However, several examples also demonstrate that indiscriminant and undocumented stocking in the Central Alpine region during the last 100 yr has simply added to the confusion already extant from naturally occurring cryptic and sibling species within these lakes. Thus, until species descriptions are forthcoming for all forms, the Central Alpine Coregonus lineage should be viewed as an "evolutionarily significant unit" (ESU), and each population a specific "management unit" (MU) within that lineage.
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do assemblages of Coregonus teleostei salmoniformes in the central alpine region of europe represent species flocks
Molecular Ecology, 1999Co-Authors: Marlis R Douglas, Patrick C Brunner, Louis BernatchezAbstract:To examine models of evolution for Coregonus from the Central Alpine region of Europe, 20 populations from nine lakes were assessed for variation at six microsatellite DNA loci. Patterns of variation were tested against three evolutionary models: phenotypic plasticity, multiple invasions of lakes by divergent forms, and within-lake radiation of species flocks. All sympatric and all but one allopatric pairs of populations were significantly divergent in allele frequencies. Pairwise F-statistics indicated reduced gene flow among phenotypically divergent sympatric populations. These results reject the hypothesis that within-lake morphological and ecological diversity reflects phenotypic plasticity within a single gene pool. Genetic similarity was higher among forms within lakes than between populations of the same form in different lakes. Among-lake divergence was primarily a product of allele size differences. Mantel tests contrasting patterns of genetic divergence against patterns predicted from the multiple invasions and species flocks models indicated that the latter is the best explanation of the observed genetic variation. Thus, reproductively isolated species diverged within lakes, with similar patterns repeatedly emerging among lakes. While this study argues for a particular mode of evolution in Central Alpine Coregonus, the taxonomy of these forms remains unresolved.
Michael D Rennie - One of the best experts on this subject based on the ideXlab platform.
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energy acquisition and allocation patterns of lake whitefish Coregonus clupeaformis are modified when dreissenids are present
Canadian Journal of Fisheries and Aquatic Sciences, 2012Co-Authors: Michael D Rennie, Timothy B Johnson, Gary W SprulesAbstract:We evaluated the effects of dreissenid-induced food web changes on rates of lake whitefish (Coregonus clupea- formis) energy acquisition and allocation in North American populations. We used mass-balance models of lake whitefish growth and methylmercury accumulation in 17 populations with and without dreissenids present to estimate and contrast rates of activity (ACT), consumption (C) and conversion efficiency (V). Historical estimates were also generated for a single lake whitefish population during dreissenid establishment. Bioenergetic estimates from both scenarios were compared with densities of Diporeia, a historically important diet component of lake whitefish. Mean lake whitefish ACT and C estimates in populations with dreissenids were significantly greater: 1.3-2 times those of populations without dreissenids. Conversion efficiencies scaled positively and significantly, while C and ACT varied negatively and significantly with Diporeia abun- dance. Our results suggest that changes in lake whitefish activity may affect density estimates — and ultimately sustainable management quotas — for this species. Our results also show that reported declines in lake whitefish individual growth rates in South Bay, Lake Huron, can be explained by increased activity rates due to increased foraging activity in an energetically depleted prey community. Resume : Nous evaluons les effets des changements dans les reseaux alimentaires occasionnes par les dreissenides sur les taux d'acquisition et d'allocation de l'energie chez le grand coregone (Coregonus clupeaformis) dans des populations nord- americaines. Des modeles de bilans massiques de la croissance et d'accumulation de methylmercure chez des grands corego- nes de 17 populations avec et sans presence de dreissenides nous ont servi a estimer et comparer les taux d'activite (ACT), de consommation (C )e t d'efficacite de conversion (V). Nous avons aussi produit des estimations historiques pour une seule population de grands coregones durant l'etablissement des dreissenides. Nous avons compare les estimations bioenergetiques des deux scenarios en fonction des densites de Diporeia, une composante historiquement importante du regime alimentaire des grands coregones. Les estimations moyennes des ACT et de C des grands coregones dans les populations avec dreisseni- des sont significativement plus grandes, 1,3-2 plus elevees, que celles des populations sans dreissenides. Les efficacites de conversion se cadrent de facon positive et significative, alors que C et ACT varient de maniere negative et significative, en fonction de l'abondance des Diporeia. Nos resultats indiquent que les changements dans l'activite des grands coregones peu- vent affecter les estimations de densite — et en bout de compte les quotas de gestion durable — chez cette espece. Nos re- sultats montrent aussi que les declins dans les taux de croissance individuelle des grands coregones signales dans South Bay, au lac Huron, peuvent s'expliquer par les taux accrus d'activite a cause d'une recherche plus importante de nourriture dans une communaute de proies appauvrie en energie. (Traduit par la Redaction)
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factors affecting the growth and condition of lake whitefish Coregonus clupeaformis
Canadian Journal of Fisheries and Aquatic Sciences, 2009Co-Authors: Michael D Rennie, Gary W Sprules, Timothy J JohnsonAbstract:Though declines in the growth and condition of Great Lakes lake whitefish (Coregonus clupeaformis) have been largely attributed to food web disruptions caused by invasive dreissenid mussels, a comp...
Timothy J Johnson - One of the best experts on this subject based on the ideXlab platform.
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factors affecting the growth and condition of lake whitefish Coregonus clupeaformis
Canadian Journal of Fisheries and Aquatic Sciences, 2009Co-Authors: Michael D Rennie, Gary W Sprules, Timothy J JohnsonAbstract:Though declines in the growth and condition of Great Lakes lake whitefish (Coregonus clupeaformis) have been largely attributed to food web disruptions caused by invasive dreissenid mussels, a comp...
