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Author L. Aulus-Giacosa, J.-C. Aymes, P. Gaudin, M. Vignon, L. Aulus-Giacosa, J.-C. Aymes, P. Gaudin, M. Vignon doi  openurl
  Title Hierarchical variance decomposition of fish scale growth and age to investigate the relative contributions of readers and scales Type Journal
  Year 2019 Publication Marine and freshwater research Abbreviated Journal  
  Volume 70 Issue 12 Pages 1828-1837  
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  Abstract Correct estimation of interindividual variability is of primary importance in models aiming to quantify population dynamics. In a fisheries context, individual information such as age and growth is often extracted using scales; however, the rationale for using a given scalimetric method (i.e. number of scales per individual and number of readers) is rarely discussed, but different sources of variance may affect the results. As a case study, we used scale growth and age of brown trout (Salmo trutta) caught in the Kerguelen Islands. Based on a nested design (readings of four scales per fish by two independent readers), we decomposed variance in growth and age according to fish (interindividual level), scales (intraindividual level) and readers by using repeatability analysis. The results highlight that most variation is attributable to fish. Readers and scales contribute little to interindividual variance, suggesting that inference was insensitive to intraorganism biological variation. Using additional scales or readers was an inefficient use of sampling resources. We argue that variance decomposition should be widely used for studies aimed at modelling natural variability in life history traits. This would improve our knowledge of the implications of measurement error, helping rationalise and define appropriate sampling strategies.  
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  Series Volume Series Issue Edition  
  ISSN 1448-6059, 1448-6059 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 8021  
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Author Sindre H. Eldøy, Jan G. Davidsen, Matthias Vignon, Michael Power doi  openurl
  Title The biology and feeding ecology of Arctic charr in the Kerguelen Islands Type Journal
  Year 2021 Publication Journal of Fish Biology Abbreviated Journal  
  Volume 98 Issue 2 Pages 526-536  
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  Abstract Subsequent to their introduction in the 1950s, Arctic charr Salvelinus alpinus have been able to establish a self-sustaining population that has adapted to the unique conditions of the sub-Antarctic Kerguelen Islands. Here, 48 individuals (198–415 mm) were caught with gillnets and their basic biology and feeding ecology were examined using stable isotope analysis. The Lac des Fougères population split use of littoral and pelagic resources evenly, although larger fish relied more heavily on littoral production and appear to follow the size-dependent life history habitat template seen in many Scandinavian lakes where smaller sized individuals occupy the pelagic zone and larger individuals dominate the littoral habitat. In Kerguelen, Arctic charr mature at the same ages (5.6 years) as Arctic charr in both sub-Arctic and Arctic lakes. Although mortality was average in comparison to comparator sub-Arctic lakes, it was high in comparison to Arctic lakes. Maximal age (>7+) was at the lower end of the range typically seen in sub-Arctic lakes. Although they inhabit a resource-poor environment, Kerguelen Arctic charr showed no evidence of cannibalism. Thus, while Arctic charr can survive and reproduce in the relatively unproductive Kerguelen lake environments, survival and growth nevertheless appear to be traded off against survival and longevity. The uniqueness of the population location and the recency of its introduction suggest that further monitoring of the population has the potential to yield valuable insights into both the adaptability of the species and its likely responses to ongoing large-scale environmental change as represented by climate change.  
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  Series Volume Series Issue Edition  
  ISSN 1095-8649 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 8178  
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Author Jacques Labonne, Aurélie Manicki, Louise Chevalier, Marin Tétillon, François Guéraud, Andrew P. Hendry doi  openurl
  Title Using Reciprocal Transplants to Assess Local Adaptation, Genetic Rescue, and Sexual Selection in Newly Established Populations Type Journal
  Year 2021 Publication Genes Abbreviated Journal  
  Volume 12 Issue 1 Pages 5  
  Keywords gene flow genetic rescue local adaptation mating success small population  
  Abstract Small populations establishing on colonization fronts have to adapt to novel environments with limited genetic variation. The pace at which they can adapt, and the influence of genetic variation on their success, are key questions for understanding intraspecific diversity. To investigate these topics, we performed a reciprocal transplant experiment between two recently founded populations of brown trout in the sub-Antarctic Kerguelen Islands. Using individual tagging and genetic assignment methods, we tracked the fitness of local and foreign individuals, as well as the fitness of their offspring over two generations. In both populations, although not to the same extent, gene flow occurred between local and foreign gene pools. In both cases, however, we failed to detect obvious footprints of local adaptation (which should limit gene flow) and only weak support for genetic rescue (which should enhance gene flow). In the population where gene flow from foreign individuals was low, no clear differences were observed between the fitness of local, foreign, and F1 hybrid individuals. In the population where gene flow was high, foreign individuals were successful due to high mating success rather than high survival, and F1 hybrids had the same fitness as pure local offspring. These results suggest the importance of considering sexual selection, rather than just local adaptation and genetic rescue, when evaluating the determinants of success in small and recently founded populations.  
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  Notes Approved yes  
  Call Number Serial 8179  
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Author Jan Grimsrud Davidsen, Xavier Bordeleau, Sindre HÃ¥varstein Eldøy, Frederick Whoriskey, Michael Power, Glenn T. Crossin, Colin Buhariwalla, Philippe Gaudin doi  isbn
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  Title Marine habitat use and feeding ecology of introduced anadromous brown trout at the colonization front of the sub-Antarctic Kerguelen archipelago Type Journal
  Year 2021 Publication Scientific Reports Abbreviated Journal  
  Volume 11 Issue 1 Pages 11917  
  Keywords Animal migration Behavioural ecology Ecology Stable isotope analysis  
  Abstract In 1954, brown trout were introduced to the Kerguelen archipelago (49°S, 70°E), a pristine, sub-Antarctic environment previously devoid of native freshwater fishes. Trout began spreading rapidly via coastal waters to colonize adjacent watersheds, however, recent and unexpectedly the spread has slowed. To better understand the ecology of the brown trout here, and why their expansion has slowed, we documented the marine habitat use, foraging ecology, and environmental conditions experienced over one year by 50 acoustically tagged individuals at the colonization front. Trout mainly utilized the marine habitat proximate to their tagging site, ranging no further than 7 km and not entering any uncolonized watersheds. Nutritional indicators showed that trout were in good condition at the time of tagging. Stomach contents and isotope signatures in muscle of additional trout revealed a diet of amphipods (68%), fish (23%), isopods (6%), and zooplankton (6%). The small migration distances observed, presence of suitable habitat, and rich local foraging opportunities suggest that trout can achieve their resource needs close to their home rivers. This may explain why the expansion of brown trout at Kerguelen has slowed.  
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  Series Volume Series Issue Edition  
  ISSN 2045-2322 ISBN 2045-2322 Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 8180  
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Author Marc Jarry, Edward Beall, Patrick Davaine, François Guéraud, Philippe Gaudin, Jean-Christophe Aymes, Jacques Labonne, Matthias Vignon doi  openurl
  Title Sea trout (Salmo trutta) growth patterns during early steps of invasion in the Kerguelen Islands Type Journal
  Year 2018 Publication Polar Biology Abbreviated Journal  
  Volume 41 Issue 5 Pages 925-934  
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  Abstract Brown trout (Salmo trutta L.) was voluntarily introduced in some rivers of the Kerguelen Islands in the 1950s–1960s. Fish originating from hatcheries rapidly colonized other streams, thanks to the early occurrence of anadromous (i.e., migratory) form. Getting insight into the success of colonization requires investigating fitness-related traits such as growth and reproductive investment. In particular, increased growth and body size—traits that are broadly related to dispersal ability—are predicted on colonization front, to the possible detriment of reproductive ability. We here report such investigation on early data following the first natural reproductions in the founder populations of Kerguelen, from 1971 to 1994, assessing the main characteristic on growth at sea and reproductive investment for both sexes. Our results reveal that growth of sea trout is excellent with individuals fully benefiting from their relatively short period of growth at sea, sizes and weights ranking among the highest recorded to date. During the reproduction period, males lose on average 15–21% of their weight, whereas females lose 18–19% of their weight. Although a trade-off between growth and reproduction may arise at marginal distribution of invasive species, our study indicates that any potential advantages arising from increased growth and therefore potential dispersal ability may not be directly balanced by reduced reproductive investment, with respect to other published studies. Results overall shed light on intrinsic invasiveness of the brown trout in a post-glacial landscape with barely any interaction with human activities.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1432-2056 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 8181  
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Author Lucie Aulus-Giacosa openurl 
  Title Spatio-temporal evolution of life history traits related to dispersal. Brown trout (Salmo trutta L.) colonization of the sub-Antarctic Kerguelen Islands. // Evolution de l'anadromie chez la truite commune (Salmo trutta) L. dans le cadre de l'expansion des populations introduites dans les îles Kerguelen. Type Thesis
  Year 2021 Publication Thèse de doctorat en Physiologie et Biologie des Organismes – Populations -Interactions Abbreviated Journal  
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  Abstract Grâce à ses capacités dispersives et adaptatives, la truite commune (Salmo trutta L.), poisson anadrome facultatif, est un bon candidat à la colonisation de nouveaux milieux. L'introduction de l'espèce dans les années 1950 dans les îles subantarctiques de Kerguelen fournit un modèle d'étude unique pour comprendre les causes et les mécanismes de la dispersion, grâce à l'étude des traits d'histoire de vie en lien avec la migration (e.g. croissance, âge à la migration). L'étude de leur évolution temporelle le long d'un front de colonisation est le cÅ“ur de ce travail de thèse. A travers l’étude des écailles recueillies dans le cadre de ce programme à long terme, les histoires de vie de près de 5000 poissons ont été reconstruites. Ce travail démontre l’importance de la méthodologie utilisée afin de reconstruire les traits de vie individuel. La modélisation de l’évolution de la croissance en eau douce, de la taille à l’âge et de l’âge à la première migration démontre que des processus évolutifs sont en Å“uvre dans les populations en expansion. Notamment, le ralentissement de la croissance avec le temps ainsi que la diminution de la taille à l’âge le long du front de colonisation laissent à penser que la capacité de dispersion diminue à mesure que les populations sont en marges de la zone d’expansion. L’évolution de la valeur seuil à la première migration confirme ce résultat, et illustre l’importance de la plasticité phénotypique et de l’adaptation locale dans le choix de la tactique migratoire. Toutefois, l’approche menée dans ce manuscrit se concentre sur l’évolution de la migration, et bénéficierait de l’étude de l’évolution conjointe des traits impliqués dans la valeur sélective (balance coûts-bénéfices), tels que la reproduction, ou la croissance en mer.  
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  Notes Approved yes  
  Call Number Serial 8354  
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Author Jacques Labonne, Mathieu Buoro, Lucie Aulus Giacosa, Matthias Vignon, Sindre HÃ¥varstein Eldøy, Jan Grimsrud Davidsen, Xavier Bordeleau, Sophia Ferchiou, France Caza, Yves St-Pierre, Stephane Betoulle, Jean-Christophe Aymes, Francois Gueraud, Andrew P. Hendry, Lucie Marandel, Stéphane Glise, Alexandre Herman, Vincent Veron, Stéphane Panserat, Philippe Gaudin doi  openurl
  Title Evolutionary Ecology of Kerguelen Islands Colonization by Introduced Salmonids: SALMEVOL 1041-2 project Type Book
  Year 2022 Publication Rapport Abbreviated Journal  
  Volume Issue Pages  
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  Abstract The present report is a synthesis of all studies conducted around the long-term ecological research (LTER) monitoring of introduced salmonid species in the sub Antarctic Kerguelen islands over the 2015- 2020 period, within the SALMEVOL-2 project. The monitoring encompasses the history of eight species, five of which are still present in Kerguelen, the data and collections spanning five decades and tenths of rivers. Based on this monitoring, but also thanks to various field experiments, we have undertaken to study the evolutionary ecology of these species, using the invasive Brown trout as flagship model, under the premise that the Kerguelen situation, where rivers were previously void of any fish species, could be an anticipation lab of the situation developing at the poles due to climate change. Our findings pertain to life history traits such as individual growth, migration between freshwater and marine ecosystems, microbiomes, but also proximal and ultimate mechanisms of adaptation in relation to the local environment. We also begin to investigate how the expanding metapopulation structure, resulting from multiple invasion events, may affect life history traits evolution.  
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  Notes Approved yes  
  Call Number Serial 8358  
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Author L. Aulus-Giacosa, F. Guéraud, P. Gaudin, M. Buoro, J. C. Aymes, J. Labonne, M. Vignon doi  openurl
  Title Human influence on brown trout juvenile body size during metapopulation expansion Type Journal
  Year 2021 Publication Biology Letters Abbreviated Journal  
  Volume 17 Issue 10 Pages 20210366  
  Keywords brown trout density dependence dispersal invasion biology subantarctic  
  Abstract Change in body size can be driven by social (density) and non-social (environmental and spatial variation) factors. In expanding metapopulations, spatial sorting by means of dispersal on the expansion front can further drive the evolution of body size. However, human intervention can dramatically affect these founder effects. Using long-term monitoring of the colonization of the remote Kerguelen islands by brown trout, a facultative anadromous salmonid, we analyse body size variation in 32 naturally founded and 10 human-introduced populations over 57 years. In naturally founded populations, we find that spatial sorting promotes slow positive changes in body size on the expansion front, then that body size decreases as populations get older and local density increases. This pattern is, however, completely different in human-introduced populations, where body size remains constant or even increases as populations get older. The present findings confirm that changes in body size can be affected by metapopulation expansion, but that human influence, even in very remote environments, can fully alter this process.  
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  Notes Approved yes  
  Call Number Serial 8373  
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Author Hervé Rogissart openurl 
  Title Caractérisation de traits de vie chez la truite commune (Salmo trutta) dans un contexte d'invasion biologique aux îles Kerguelen Type Master 1
  Year 2019 Publication Abbreviated Journal  
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  Call Number Serial 8382  
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Author Sophia Ferchiou, France Caza, Richard Villemur, Jacques Labonne, Yves St-Pierre doi  openurl
  Title Skin and Blood Microbial Signatures of Sedentary and Migratory Trout (Salmo trutta) of the Kerguelen Islands Type Journal
  Year 2023 Publication Fishes Abbreviated Journal  
  Volume 8 Issue 4 Pages 174  
  Keywords Salmo trutta 16S rRNA blood microbiome fish Kerguelen Islands migration skin microbiome  
  Abstract Our understanding of how microbiome signatures are modulated in wild fish populations remains poorly developed and has, until now, mostly been inferred from studies in commercial and farmed fish populations. Here, for the first time, we have studied changes in the skin and blood microbiomes of the Salmo trutta population of the volcanic Kerguelen archipelago located at the northern limit of the Antarctic Ocean. The Kerguelen Islands present a natural framework of population expansion and reveal a likely situation representing further climate change in distribution areas. Our results showed that S. trutta of the Kerguelen Islands has a microbiome signature distinct from those of salmonids of the Northern Hemisphere. Our study also revealed that the skin and blood microbiomes differ between sedentary and migratory S. trutta. While 18 phyla were shared between both groups of trout, independent of the compartment, 6 phyla were unique to migratory trout. Further analyses showed that microbiome signatures undergo significant site-specific variations that correlate, in some cases, with the peculiarity of specific ecosystems. Our study also revealed the presence of potential pathogens at particular sites and the impact of abiotic factors on the microbiome, most notably due to the volcanic nature of the environment. This study contributes to a better understanding of the factors that modulate the microbiome signatures of migratory and sedentary fish populations. It will also help to better monitor the impacts of climate change on the colonization process in the sub-Antarctic region.  
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  ISSN 2410-3888 ISBN Medium  
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  Notes Approved yes  
  Call Number Serial 8404  
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