Ephemeral floodplain habitats provide best growth conditions for juvenile Chinook salmon in a California river
- 1.1k Downloads
We reared juvenile Chinook salmon for two consecutive flood seasons within various habitats of the Cosumnes River and its floodplain to compare fish growth in river and floodplain habitats. Fish were placed in enclosures during times when wild salmon would naturally be rearing in floodplain habitats. We found significant differences in growth rates between salmon reared in floodplain and river enclosures. Salmon reared in seasonally inundated habitats with annual terrestrial vegetation experienced higher growth rates than those reared in a perennial pond on the floodplain. Growth of fish in the non-tidal river upstream of the floodplain varied with flow in the river. When flows were high, there was little growth and high mortality, but when the flows were low and clear, the fish grew rapidly. Fish displayed very poor growth in tidally influenced river habitat below the floodplain, a habitat type to which juveniles are commonly displaced during high flow events due to a lack of channel complexity in the main-stem river. Overall, ephemeral floodplain habitats supported higher growth rates for juvenile Chinook salmon than more permanent habitats in either the floodplain or river. Variable responses in both growth and mortality, however, indicate the importance of providing habitat complexity for juvenile salmon in floodplain reaches of streams, so fish can find optimal places for rearing under different flow conditions.
KeywordsJuvenile Chinook Floodplain Rearing Growth Restoration
We thank the California Bay Delta Authority Science Program and The David and Lucile Packard Foundation for financial support of this project. We are grateful to the Cosumnes River Preserve for their support and access to the preserve. We would also like to express our appreciation for their help in the study design and field assistance to Wendy Trowbridge and Alicia Gilbreath. We thank the reviewers and the editor for their comments.
- Bay-Delta Authority CALFED (2004) Ecosystem Restoration Multi-Year Program Plan (Years 5–8). Sacramento, CaliforniaGoogle Scholar
- Healey MC (1980) Utilization of the Nanaimo River estuary by juvenile Chinook salmon, Oncorhynchus tshawytscha. Fish Bull (Wash D C) 77:653–668Google Scholar
- Junk WJ, Bayley PB, Sparks RE (1989) The flood pulse concept in river-floodplain systems. Special publication. Can J Fish Aquat Sci 106:110–127Google Scholar
- Kjelson MA, Raquel PF, Fisher FW (1981) The life-history of fall run juvenile Chinook salmon, Oncorhynchus-Tshawytscha, in the Sacramento San Joaquin Estuary of California. Estuaries 4:285–285Google Scholar
- Mount JF (1995) California rivers and streams. University of California Press, BerkeleyGoogle Scholar
- Moyle PB, Crain PK, Whitener K (2007) Patterns in the use of a restored California floodplain by native and alien fishes. San Francisco Estuary and Watershed Science 5(3):1–27. http://repositories.cdlib.org/jmie/sfews/vol5/iss3/art1/
- Swenson RO, Whitener K, Eaton M (2003) Restoring floods on floodplains: riparian and floodplain restoration at the Cosumnes River Preserve. In: Faber PM (ed) California riparian systems: processes and floodplains management, ecology, and restoration. 2001 Riparian Habitat and Floodplains Conference Proceedings. Riparian Habitat Joint Venture. Riparian Habitat Joint Venture, Sacramento, CA, pp 224–229Google Scholar
- Tockner K, Stanford JA (2002) Riverine flood plains: present state and future trends. Environ Conserv 29:308–330Google Scholar