Persistent high hatchery recruitment despite advanced reoligotrophication and significant natural spawning in a whitefish

Détails

Ressource 1Télécharger: Wedekind et al. Glob Ecol Conserv 22.pdf (1756.98 [Ko])
Etat: Public
Version: Final published version
Licence: CC BY 4.0
ID Serval
serval:BIB_9F8E5B53D433
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Persistent high hatchery recruitment despite advanced reoligotrophication and significant natural spawning in a whitefish
Périodique
Global Ecology and Conservation
Auteur⸱e⸱s
Wedekind Claus, Vonlanthen Pascal, de Guttry Christian, Stadelmann Richard, Stadelmann Noah, Pirat Aurélien, Perroud Giulia
ISSN
2351-9894
Statut éditorial
Publié
Date de publication
10/2022
Peer-reviewed
Oui
Volume
38
Pages
e02219
Langue
anglais
Résumé
Many lakes of the pre-Alpine region suffered from severe eutrophication that affected the natural reproduction of whitefish (Coregonus spp.) and necessitated large-scale supportive breeding programs. With the advanced reoligotrophication, it is now important to evaluate the relevance of continued artificial breeding for population dynamics. We focused on a whitefish population of a lake that has reached phase III of the reoligotrophication, i.e., lake biomass production is declining since 2012 in response to low phosphorus concentrations. We show that most eggs are naturally spawned, the observed oxygen concentrations would again support embryo development at all depths, and ready-to-hatch embryos can indeed be found on spawning grounds. We marked all hatchery-produced eggs of the 2014 cohort with Alizarin red, stocked them as usual (at larval or early juvenile stages), and recaptured them over a period of five years. Fish were aged from yearly growth rings on scales, and otoliths were checked for marks. We found 90.3% of the 2014 cohort to be hatchery-born. This ratio did not decline with fish age. We also determined juvenile growth of the cohorts 2012-2020 (based on the first annual ring on scales) and found that stocking intensity predicted juvenile growth (r2 = 0.67). This strong density dependence of individual growth suggests that stocking has largely determined cohort size over the first nine years of reoligo¬trophication phase III. We conclude that large areas of spawning grounds allow again for successful embryogenesis, that large quantities of eggs are naturally spawned, but that natural recruitment is significantly reduced by ecological or evolutionary factors, e.g., competition with hatchery-born fish, desynchronization of trophic interactions, or long-term effects of fishing- or hatchery-induced evolution.
Mots-clé
Nature and Landscape Conservation, Ecology, Ecology, Evolution, Behavior and Systematics
Web of science
Open Access
Oui
Financement(s)
Fonds national suisse / Projets / 31003A_182265
Création de la notice
04/07/2022 12:12
Dernière modification de la notice
11/07/2023 5:55
Données d'usage