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Personne :
Côté, Guillaume

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Côté

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Guillaume

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Université Laval. Département de biologie

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ncf11907433

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Voici les éléments 1 - 3 sur 3
  • PublicationAccès libre
    Impact des interactions gène-environnement sur l'expression de deux gènes reliés à la croissance chez l'omble de fontaine, Salvelinus fontinalis
    (2007) Côté, Guillaume; Bernatchez, Louis; Blier, Pierre.
    Le rôle des interactions génotype/environnement comme facteur responsable de la variation phénotypique dans différents environnements est depuis longtemps établi. Par contre, la connaissance de l’architecture moléculaire qui est sous-jacente à ces interactions GxE est limitée. Dans cette optique, l’objectif général de la présente étude est d’étudier les interactions entre l’environnement, le sexe, la valeur génétique et le niveau d’expression de deux gènes clés associés au système (récepteur de l’hormone de croissance, GHR et le facteur analogue à l’insuline, IGF-1) GH/IGF et de déterminer l’influence de ces interactions sur la croissance chez l’omble de fontaine, Salvelinus fontinalis. Les résultats ont démontré que i) la croissance des poissons a été supérieure en eau douce et que les mâles ont montré une croissance plus élevée, ii) le niveau d’expression des gènes liés à l’axe GH/IGF était plus élevé en milieu salé iii) les mâles ont montré un niveau d’expression de GHR et IGF-1 plus élevé que les femelles, iv) la présence d’interactions GxE pour le niveau d’expression de chaque gène. Ce projet représente un avancement dans la compréhension des impacts environnementaux et sexuels sur la relation entre l’activité des gènes et l’occurrence du phénotype.
  • PublicationAccès libre
    Quantifying relative fish abundance with eDNA : a promising tool for fisheries management
    (Wiley, 2016-01-18) Lacoursiere-Roussel, Anaïs; Bernatchez, Louis; Gauthier, Véronique; Côté, Guillaume
    Assessment and monitoring of exploited fish populations are challenged by costs, logistics and negative impacts on target populations. These factors therefore limit large-scale effective management strategies. Evidence is growing that the quantity of eDNA may be related not only to species presence/absence, but also to species abundance. In this study, the concentrations of environmental DNA (eDNA) from a highly prized sport fish species, Lake Trout Salvelinus namaycush (Walbaum 1792), were estimated in water samples from 12 natural lakes and compared to abundance and biomass data obtained from standardized gillnet catches as performed routinely for fisheries management purposes. To reduce environmental variability among lakes, all lakes were sampled in spring, between ice melt and water stratification. The eDNA concentration did not vary significantly with water temperature, dissolved oxygen, pH and turbidity, but was significantly positively correlated with relative fish abundance estimated as catch per unit effort (CPUE), whereas the relationship with biomass per unit effort (BPUE) was less pronounced. The value of eDNA to inform about local aquatic species distribution was further supported by the similarity between the spatial heterogeneity of eDNA distribution and spatial variation in CPUE measured by the gillnet method. Synthesis and applications. Large-scale empirical evidence of the relationship between the eDNA concentration and species abundance allows for the assessment of the potential to integrate eDNA within fisheries management plans. As such, the eDNA quantitative method represents a promising population abundance assessment tool that could significantly reduce the costs associated with sampling and increase the power of detection, the spatial coverage and the frequency of sampling, without any negative impacts on fish populations.
  • PublicationRestreint
    Effective number of breeders in relation to census size as management tools for Atlantic salmon conservation in a context of stocked populations
    (Springer, 2015-07-21) Perrier, Charles; Bernatchez, Louis; April, Julien; Dionne, Mélanie; Côté, Guillaume
    Monitoring short-term fluctuations in effective population sizes (N e) and effective number of breeders (N b), as well as their ratio to adult census population size (N e/N c and N b/N c), provide insight into population demography and inform conservation programs towards limiting long-term loss of evolutionary potential in wild populations. In this study, we monitored short-term variations of N b and N b/N c over three consecutive years for nine Atlantic salmon populations from Quebec, Canada. We documented how these population genetic parameters were influenced by anadromous population size as well as yearly and long-term stocking intensity. Towards this end, 15 microsatellites were used to genotype about 100 one-year-old parrs for each of three consecutive years for nine genetically distinct populations (total n = 2506) from Québec, Canada. Yearly stocking intensity had a negative effect on N b/N c, possibly as a consequence of a reduced reproductive contribution of stocked relative to wild fish. However, the impact of long-term stocking intensity on N b/N c was not significant, which may indicate relatively weak carry-over effects of stocking on future generations. Also, N b/N c was negatively correlated with N C, suggesting compensatory mechanisms, as previously reported in other salmonids. Overall, this study provides evidence of relatively weak and short-term effect of stocking on N b/N c ratio in Atlantic salmon populations and suggests potential biological mechanisms leading to the significant negative relationship between N b/N c and N c.