Population genetics of the American eel (Anguilla rostrata): FST = 0 and North Atlantic Oscillation effects on demographic fluctuations of a panmictic species |
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Authors: | Caroline L Côté Pierre‐Alexandre Gagnaire Vincent Bourret Guy Verreault Martin Castonguay Louis Bernatchez |
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Institution: | 1. Département de Biologie, IBIS (Institut de Biologie Intégrative et des Systèmes), Université Laval, , Québec, Canada, G1V 0A6;2. Direction de l'Expertise du Bas‐Saint‐Laurent, Ministère des Ressources Naturelles et de la Faune, , Rivière‐du‐Loup, Québec, Canada, G5R 1C8;3. Institut Maurice‐Lamontagne, Ministère des Pêches et des Océans, , Mont‐Joli, Québec, Canada, G5H 3Z4 |
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Abstract: | We performed population genetic analyses on the American eel (Anguilla rostrata) with three main objectives. First, we conducted the most comprehensive analysis of neutral genetic population structure to date to revisit the null hypothesis of panmixia in this species. Second, we used this data to provide the first estimates of contemporary effective population size (Ne) and to document temporal variation in effective number of breeders (Nb) in American eel. Third, we tested for statistical associations between temporal variation in the North Atlantic Oscillation (NAO), the effective number of breeders and two indices of recruit abundance. A total of 2142 eels from 32 sampling locations were genotyped with 18 microsatellite loci. All measures of differentiation were essentially zero, and no evidence for significant spatial or temporal genetic differentiation was found. The panmixia hypothesis should thus be accepted for this species. Nb estimates varied by a factor of 23 among 12 cohorts, from 473 to 10 999. The effective population size Ne was estimated at 10 532 (95% CI, 9312–11 752). This study also showed that genetically based demographic indices, namely Nb and allelic richness (Ar), can be used as surrogates for the abundance of breeders and recruits, which were both shown to be positively influenced by variation during high (positive) NAO phases. Thus, long‐term genetic monitoring of American glass eels at several sites along the North American Atlantic coast would represent a powerful and efficient complement to census monitoring to track demographic fluctuations and better understand their causes. |
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Keywords: | American eel conservation biology demographic variation North Atlantic Oscillation genetic diversity— empirical fisheries wildlife management |
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