Juvenile life history diversity is associated with lifetime individual heterogeneity in a migratory fish
- Washington Cooperative Fish and Wildlife Research Unit, School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA
- Washington Department of Fish and Wildlife North Olympia Washington USA
- National Marine Fisheries Service Northwest Fisheries Science Center Seattle Washington USA
- Yakama Nation Fisheries, Mid‐Columbia Field Station Peshastin Washington USA
- US Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, School of Environmental and Forest Sciences &, School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA
Abstract Differences in the life history pathways (LHPs) of juvenile animals are often associated with differences in demographic rates in later life stages. For migratory animals, different LHPs often result in animals from the same population occupying distinct habitats subjected to different environmental drivers. Understanding how demographic rates differ among animals expressing different LHPs may reveal fitness trade‐offs that drive the expression of alternative LHPs and enable better prediction of population dynamics in a changing environment. To understand how demographic outcomes and their relationships with environmental variables differ among animals with different LHPs, we analyzed a long‐term (2006–2021) mark–recapture dataset for Chinook salmon ( Oncorhynchus tshawytscha ) from the Wenatchee River, Washington, USA. Distinct LHPs represented in this population include either remaining in the natal stream until emigrating to the ocean as a 1‐year‐old (natal‐reach rearing) or emigrating from the natal stream and rearing in downstream habitats for several months before completing the emigration to the ocean as a 1‐year‐old (downstream rearing). We found that downstream‐rearing fish emigrated to the ocean 19 days earlier on average and returned as adults from the ocean at higher rates. We detected a positive correlation between rate of return from the ocean by downstream‐rearing fish and coastal upwelling in their spring of outmigration, whereas for natal‐reach‐rearing fish we detected a positive correlation with sea surface temperature during their first marine summer. Different responses to environmental variability should lead to asynchrony in adult abundance among juvenile LHPs. A higher proportion of downstream‐rearing fish returned at younger ages compared with natal‐reach‐rearing fish, which contributed to variability in age at reproduction and greater mixing across generations. Our results demonstrate how diversity in juvenile LHPs is associated with heterogeneity in demographic rates during subsequent life stages, which can in turn affect variance in aggregate population abundance and response to environmental change. Our findings underscore the importance of considering life history diversity in demographic analyses and provide insights into the effects of life history diversity on population dynamics and trade‐offs that contribute to the maintenance of life history diversity.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1909061
- Journal Information:
- Ecosphere, Journal Name: Ecosphere Journal Issue: 1 Vol. 14; ISSN 2150-8925
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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