Headquarters, Seattle Laboratory
Puget Sound fall Chinook estuarine utilization
The widespread loss of estuarine and nearshore habitats throughout Puget Sound comes at a price. Puget Sound Chinook salmon are just one of many species whose populations have declined to precariously low levels (ESA threatened status) due to a variety of perturbations, including estuarine and coastal development. Juvenile fall Chinook salmon utilize a number of habitats during their migration to the open ocean. One important habitat is the estuary, particularly tidal deltas, which provide a migratory corridor, protection from predators, and opportunity to forage, grow and adapt to seawater. Monitoring and restoration efforts within the tidal delta and nearshore habitats of large river deltas are becoming common throughout Puget Sound. Therefore, a pre-restoration baseline that includes characterization of life history types, estuary residence times, growth rates, and habitat use is needed for evaluating the potential response to restoration efforts by natural and hatchery origin fall Chinook salmon, for determining restoration success and complementing monitoring efforts.
The Western Fisheries Research Center has partnered separately with both the Skagit River System Tribal Cooperative and the Nisqually Tribe to research the use of otoliths (calcium carbonate deposits beneath the brain used in hearing and balance that grow in proportion to the overall growth of the fish) as a tool in examination of Puget Sound Fall Chinook salmon life history. Residence times and growth rates in various habitats, and the overall importance of estuarine utilization to juveniles as well as the returning adult population are the focus of the research.
These projects have developed over the years to include a large body of information on Fall Chinook salmon from two main river deltas within Puget Sound: the Skagit River and the Nisqually River. The Skagit River basin baseline research is near completion for three brood years of wild fall Chinook consisting of juvenile out-migrants and the corresponding adult returns under varying density conditions from year to year for the out-migrant population. The Nisqually River basin research is currently in the final stages of completing pre-restoration baseline information from three brood years of natural and hatchery fall Chinook, consisting of juvenile out-migrants and the corresponding adult returns. Information is currently being collected on several years of natural and hatchery juvenile fall Chinook out-migrant samples following restoration efforts in the Nisqually delta.
The Skagit River tidal delta habitat.
Nisqually Delta Restoration website.
Lind-Null, A., and K. Larsen. 2011. Validation of a Freshwater Otolith Microstructure Pattern for Nisqually Chinook Salmon (Oncorhynchus tshawytscha). Nisqually Indian Tribe, Department of Natural Resources, Salmon Recovery Program, Technical Report No. 2011-1, 13 p.
Lind-Null, A., and K. Larsen. 2010. Otolith analysis of pre-restoration habitat use by Chinook salmon in the delta-flats and nearshore regions of the Nisqually River Estuary. USGS Open-File Report: 2010-1238, 28 p.
Beamer, E., A.McBride, C. Greene, R. Henderson, G. Hood, K. Wolf, K. Larsen, C. Rice, and K. Fresh. 2005. Delta and nearshore restoration for the recovery of wild Skagit River Chinook salmon: Linking estuary restoration to wild Chinook salmon populations. Supplement to: Skagit Chinook Recovery Plan, 94 p.
Beamer, E., and K. Larsen. 2004. The importance of Skagit delta habitat on the growth of wild ocean-type Chinook in Skagit Bay: Implications for delta restoration. Skagit River System Cooperative Research Program, 6 p.
Beamer, E.M., J.C. Sartori, and K.A. Larsen. 2000. Skagit Chinook life history study Progress Report Number 3. Prepared for the Non-Flow Coordination Committee (NCC) under the Chinook Research Program in the Non-flow Mitigation part of the Skagit Fisheries Settlement Agreement. Federal Energy Regulatory Commission Project Number 553, 19 p.
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