Crescent Harbor Creek is a small stream located on Whidbey Island just north of Crescent Harbor, on Naval Air Station Whidbey Island (NASWI). The stream drains into the northwestern edge of the Crescent Harbor Salt Marsh, a 206-acre tidal channel wetland that is the site of a large pocket estuary restoration that was completed by the Skagit River System Cooperative (SRSC) and the US Navy in 2009. The stream channel in this reach has been diked and diverted from its historic alignment into an incised ditch, reducing channel length and increasing flow velocity. Completion of restoration work at Crescent Harbor Creek will add to the quality and capacity of this important rearing site for juvenile salmonids.
This proposal includes restoring native vegetation on 14 acres and controlling invasive species for one year on 42 acres of riparian buffer along the mainstem Skagit River. This proposal would create a 300-foot riparian buffer along the Skagit River and a 150-foot buffer along a winter-wetted swale within a conservation easement in the Skagit River floodplain. It is part of a larger project with additional secured funding that aims to restore native vegetation on 55 acres, control invasive species on 60 acres in three different sites along the Skagit River and Illabot Creek (within the Skagit River floodplain), and maintain the sites for at least three years.
The Similk Tidal Marsh Restoration Project is located at the northern end of Similk Bay along the southern shoreline of Fidalgo Island, Skagit County, Washington State, USA. This project will develop a preliminary design for a construction action that will breach a dike and roadway on Similk Beach to restore tidal flow and fish access to a 17-acre pocket estuary. Pocket estuaries are small tidal marshes in the nearshore environment that are not directly associated with a river or large stream, and they provide critical rearing habitats for juvenile Chinook salmon transitioning from freshwater to marine conditions. The potentially restored pocket estuary in Similk Bay is one of twelve pocket estuaries available to juvenile Chinook salmon within a one-day migration from the Skagit River delta, so this is a rare opportunity to restore an important habitat type. In addition to Chinook, this project will also likely benefit chum, coho, and salmon prey species including Pacific herring, surf smelt, and sand lance.
We propose a workshop to review the current approaches to assessing and modelling salmon survival across freshwater/coastal and marine life history stages and to recommend options that will inform the host of management tools/processes that require consideration of the full life history. We will bring together experts possessing experience with these techniques to share their knowledge in a structured manner. Case studies drawn from Pacific Salmon Treaty stocks that have requisite information will be developed that can be used to test the modelling approach. A Workshop Technical Planning Team will be convened from North Pacific Anadromous Fish Commission -International Year of the Salmon partner government agencies, NGO’s and academia to ensure relevance of the work to management and to assist in identifying a complete complement of experts. Experts will include representatives from Pacific Salmon Commission Secretariat staff and Technical Committees (Chinook, Coho, Chum and Sockeye). We will support travel for experts from Asia, Canada, Europe and the U.S. to attend. It will be essential for us to incorporate approaches to understanding freshwater and marine ecosystem status with Indigenous Peoples. Additionally, we will assess the potential for the development of new and emerging technologies and citizen science to augment this work.
Age data derived from scale, whole otolith, and otolith thermal mark analyses are critical to sustainable fisheries management and the assessment of salmon fisheries and to evaluate recovery efforts for imperilled salmon populations. However, to our knowledge, a formal comparison of age estimates derived from these methods has not been completed for Chum and Sockeye salmon. The objective of this proposal is to provide corroboration of age estimates that are paramount to the run-reconstruction, in-season fishery management, and forecasts of these stocks. We propose to compare paired age estimates derived from scale (Chum) and whole otolith (Sockeye) analysis and otolith thermal mark analysis (Chum and Sockeye) for greater than 12,500 adult Chum and Sockeye salmon over the last two decades in Washington State. This analysis will identify the level of precision between estimates and any bias between methods and directly addresses Southern panel priority of improving salmon escapement assessments.
Since 2015, the Washington Department of Fish and Wildlife (WDFW) has been working to improve Chum escapement estimates resulting in two technical reports (Edwards and Zimmerman 2018; Ronne et al. 2019). Previous work assessed distribution inside versus outside index reaches, area-under-the-curve estimates within index reaches, carcass tagging estimates of abundance in select index reaches, estimates of spawner stream life duration, and total spawner abundance of Chum salmon within tributaries of Grays Harbor. This proposal seeks to further implement an accurate and precise method for estimating escapement of Chum in sub-basins yet to be evaluated. Utilizing new methods, we also seek to revise run size estimates of historical abundance. This methodology can be used in other systems throughout the area covered by the Pacific Salmon Treaty. Current escapement estimates in Puget Sound and coastal Washington are derived from methods developed in the 1970s with the understanding that those methods were based on unsubstantiated assumptions that would later be revisited and refined. Over 40 years later, those methods are still being used for escapement estimates. Chum have become a constraining stock on the Grays Harbor salmon fisheries. Therefore, refined Chum assessments may alter management strategies moving forward.
The proposed work will address Southern Panel Priority #3: Coho Biological Studies, with the specific objective of understanding the effect of climate change on salmon life history with benefit to pre-season forecasts. One of the simplest coho forecast methods involves a sibling regression model, which uses the abundance of returning males (i.e., jacks – fish that return to freshwater after spending only ~6 months at sea) as an indicator of adult returns. These models are based on an association between jack marine survival in the first few months at sea and adult marine survival the following year. The models rely on a stable age structure, an assumption that does not always hold. Marine survival of wild coho salmon in coastal Washington is measured at Bingham Creek, the site of a long-term life-cycle monitoring program operated by the Washington Department of Fish and Wildlife. Marine survival estimates inform pre-season forecasts, and are important in the determination of allowable exploitation rates in bilateral fisheries. Estimates of survival come from release and recovery of coded-wire tagged (CWT) wild coho marked as smolts during the outmigration period and recovered as adults from fisheries and a weir trap. Preliminary analysis established an inverse relationship between rearing streamflow rates and jack survival.
The proposed work will expand on these observations and evaluate the effects of rearing temperature on jack rates. The goal is to make predictions about age-at-maturity by utilizing spatial stream network models of stream temperature (“Thermalscapes”) for the Grays Harbor coho population. The models can be used to hindcast and forecast rearing temperature based on variations in air temperature and streamflow, which allows for analyzing historical data in addition to predicting jack rates under future climate scenarios.
This proposal seeks to expand the Chum SNP baseline to identify fall-, winter-, and summer-run Chum salmon population contributions to mixed fisheries in the Southern Boundary area. Southern Boundary Chum salmon populations have been in general decline yet have recently become a higher priority fishery. Fisheries have shifted to Chum salmon because Chinook salmon have declined and their harvest is restricted. Further, resident Orca Whales, also in decline in Puget Sound, prefer Chinook salmon and are another factor diverting fishing effort to Chum salmon. Several rivers in the Strait of Juan de Fuca and North Puget Sound support Chum salmon, including the Elwha, Nooksack, Snohomish, Skagit, and Stillaguamish rivers. Although wild Chum salmon numbers are low, Tribal and Washington Department of Fish and Wildlife (WDFW) hatcheries maintain Tribal and non-tribal fishing while supporting wild populations. However, because Chum salmon from a hatchery are generally unmarked, we conduct marine fisheries without information on the contributions of specific stocks or hatchery programs to the fishery. Due to the recent elevated importance of the Chum salmon fishery, both the Tribes and WDFW require information to manage fisheries to protect weak stocks and to ensure that fish return to terminal areas. Further, for fisheries in the Southern Boundary area, we need to identify fishery components to adhere to guidelines in the Pacific Salmon Treaty regarding Chum salmon harvest limits by U.S. fishers in relation to Fraser Chum salmon abundance.
This project will identify components of two mixed fisheries over four years to better understand the origins and abundance of wild and hatchery Chum salmon harvested in Strait of Juan de Fuca and North Puget Sound throughout the season.
Producing more hatchery Chinook salmon juveniles has recently been proposed in Washington State with hopes of enhanced ecosystem and fisheries benefits. However, it has recently been shown that even the vast North Pacific Ocean cannot support an infinite number of salmon (Ruggerone and Irvine 2018), and it appears that mortality of salmon in the Salish Sea can also be density dependent (Ruggerone and Goetz 2004). Density-dependent effects between pink salmon in particular (the most numerous species, but also chum salmon) and Chinook salmon have been documented by an increasing number of studies (e.g., Ruggerone and Nielsen 2004; Ruggerone et al. 2003), suggesting that salmon compete for food in the ocean, which can lead to reduced growth, delayed age at maturation, and lower survival rates (Ruggerone and Irvine 2018). Preliminary analyses of the relationships between Chinook salmon hatchery production and numbers surviving to adulthood suggest reduced Chinook survival in years when large numbers of juvenile pink salmon also out-migrate. In some regions, this density-dependent mortality may be so strong that large increases in hatchery releases may limit the number of returning adults.
We propose to evaluate the following questions: what Chinook salmon juvenile release abundance values are associated with greatest marine survival rates? How do survival rates vary with different numbers of juvenile pink salmon out-migrating in the Salish Sea? How do these relationships differ among Chinook salmon stocks from various regions of the Salish Sea?
S19-SP33 Optimization of hatchery Chinook releases in the Salish Sea through ecosystem-based management 2019 Report
The objectives of this project are to 1) identify environmental and biological factors related to variation in marine growth and productivity of Puget Sound Chum salmon (Oncorhynchus keta); and 2) develop stock specific indicators of productivity and survival based on marine growth and environmental indices for forecasting. Previous research examining early marine growth and survival of Puget Sound Chinook salmon (O. tshawytscha) in relation to biological and environmental factors provided an approach to understanding mechanisms related to mortality during the marine period (Campbell et al. 2017, Claiborne et al. in prep). The result of this work is a useful tool used for forecasting fall Chinook salmon in South Puget Sound (WDFW Puget Sound Management Unit, unpublished data).
This proposal will generate early marine growth estimates from scale analysis of archived samples (WDFW Fish Ageing Laboratory) for fall-run Chum salmon for 15 brood years and relate early marine growth to trends in productivity and survival throughout Puget Sound. To assess bottom-up and top-down processes that may be driving variation in productivity, we will examine relationships between marine growth and environmental indices, which will include both large- and regional-scale metrics. For each stock, we will develop predictive models of productivity and survival incorporating environmental indices and annual growth estimates, and use hind-casting to evaluate model performance through time.