Separating wild versus stocking components in fish recruitment without identification data: a hierarchical modelling approach

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Dauphin, Guillaume, Brugel, Catherine, Legrand, Marion, Prévost, Etienne
• Other Authors: Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP), Institut National de la Recherche Agronomique (INRA)-Université de Pau et des Pays de l'Adour (UPPA), Canadian Rivers Institute, Department of Biology, University of New Brunswick (UNB), Délégation interrégionale Massif Central, Office national de l'eau et des milieux aquatiques (ONEMA), Ministère de l'écologie, du développement durable et de l'énergie-Ministère de l'écologie, du développement durable et de l'énergie, Loire Grands Migrateurs (Logrami), This research was part of the Plan Loire Grandeur Nature and financially supported by the European Regional Development Fund, the Agence de l’eau Loire Bretagne, and the Etablissement public Loire.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: salmon; atlantic; restocking; recrutement naturel; repeuplement; programme de repeuplement; salmo salar; modèle bayésien; modèle hiérarchique; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Atlantic salmon; Salmo salar
• Online Access: https://hal.archives-ouvertes.fr/hal-01606740; https://doi.org/10.1139/cjfas-2015-0443

International audience Salmonid juvenile stocking programs are often poorly monitored due to the lack of identification between stocked and wild fish. In this study, a hierarchical Bayesian model is developed to take advantage of spatiotemporal variations of stocking and wild recruitment for estimating these two components despite the absence of identification data. It is first tested by means of simulated data and then applied to the 37 year abundance data set of the Atlantic salmon (Salmo salar) population of the Allier catchment (France). Despite the absence of identification data, juvenile densities could be estimated and split into wild and stocked components. We found that the stocked juveniles contributed significantly to the total juvenile production, while the wild reproduction continued to provide an important contribution. This approach is encouraging and promising from a management advice perspective. It is flexible enough to accommodate for case study specificities and shows that long-term monitoring abundances can be useful to assess the impact of stocking programs even in the absence of direct means of identifying stocked versus wild fish.