1. Kootenay Lake kokanee (Oncorhynchus nerka) collapse into a predator pit
- Author
-
Warnock, Will G., Thorley, Joseph L., Arndt, Steven K., Weir, Tyler J., Neufeld, Matthew D., Burrows, Jeff A., and Andrusak, Greg F.
- Subjects
Kootenay National Park, British Columbia -- Natural resources ,Fish populations -- Thinning ,Sockeye salmon -- Statistics -- Protection and preservation ,Predation (Biology) -- Models ,Rainbow trout -- Environmental aspects -- Behavior ,Fishery management -- Research ,Earth sciences - Abstract
Kootenay Lake is a large, oligotrophic waterbody in southern British Columbia renowned for recreational fisheries for piscivorous rainbow trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus). Long-term datasets showed an increase in large-bodied (>2 kg) piscivore abundance followed by a collapse of the kokanee (Oncorhynchus nerka) prey population in 2013 and subsequent decline of large-bodied piscivores. An unprecedented post-collapse state formed in 2015-2018, characterized by low kokanee spawner abundance and biomass and high catch rates for small-bodied ( Le lac Kootenay est un grand plan d'eau oligotrophe du sud de la Colombie-Britannique, reconnu pour ses peches sportives a la truite arc-en-ciel (Oncorhynchus mykiss) et a l'omble a tete plate (Salvelinus confluentus), deux especes piscivores. Des ensembles de donnees sur de longues periodes montrent une augmentation de l'abondance de grands (>2 kg) piscivores suivie de l'effondrement de la population de kokanis (Oncorhynchus nerka), des proies, en 2013 et le declin subsequent des grands piscivores. Une situation sans precedent est apparue dans la foulee de l'effondrement, en 2015-2018, caracterisee par une faible abondance et une faible biomasse de kokanis geniteurs et des taux de prises eleves de petits piscivores (, Introduction Large lake and reservoir ecosystems in northwestern North America often contain populations of large-bodied piscivorous salmonids. These fish are commonly supported by a relatively simple foodweb in the pelagic [...]
- Published
- 2022
- Full Text
- View/download PDF