The density dilemma: limitations on juvenile production in threatened salmon populations
Ecology of Freshwater Fish
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Abstract
Density-dependent processes have repeatedly been shown to have a central role in salmonid population dynamics, but are often assumed to be negligible for populations at low abundances relative to historical records. Density dependence has been observed in overall spring/summer Snake River Chinook salmon Oncorhynchus tshawytscha production, but it is not clear how patterns observed at the aggregate level relate to individual populations within the basin. We used a Bayesian hierarchical modelling approach to explore the degree of density dependence in juvenile production for nine Idaho populations. Our results indicate that density dependence is ubiquitous, although its strength varies between populations. We also investigated the processes driving the population-level pattern and found density-dependent growth and mortality present for both common life-history strategies, but no evidence of density-dependent movement. Overwinter mortality, spatial clustering of redds and limited resource availability were identified as potentially important limiting factors contributing to density dependence. The ubiquity of density dependence for these threatened populations is alarming as stability at present low abundance levels suggests recovery may be difficult without major changes. We conclude that density dependence at the population level is common and must be considered in demographic analysis and management.
Suggested Citation
Walters, A.W., Copeland, T., Venditti, D.A., 2013, The density dilemma: limitations on juvenile production in threatened salmon populations: Ecology of Freshwater Fish, Early View, https://doi.org/10.1111/eff.12046.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | The density dilemma: limitations on juvenile production in threatened salmon populations |
| Series title | Ecology of Freshwater Fish |
| DOI | 10.1111/eff.12046 |
| Publication Date | March 31, 2013 |
| Year Published | 2013 |
| Language | English |
| Publisher | Wiley |
| Contributing office(s) | Coop Res Unit Seattle |
| Description | Early View |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Ecology of Freshwater Fish |
| Country | United States |