Terms of Reference

Revised Escapement Goals for Okanagan Basin Sockeye Salmon in British Columbia

Regional Peer Review - Pacific Region

November 21-22, 2023

Kelowna, BC

Co-Chairs: Cameron Freshwater and Dawn Machin

Context

The Columbia River Basin supports a Sockeye Salmon (Oncorhynchus nerka) aggregate that is composed of three Sockeye populations: the Okanagan basin stocks from British Columbia (BC), Canada, the Lake Wenatchee population from Washington State, and a very small population from Redfish Lake in Idaho (Williams et al. 2014) that is listed under the United States (US) Endangered Species Act (ESA). On average since 2008, Okanagan basin Sockeye account for greater than 80% of all Sockeye returning to the Columbia Basin (Hyatt and Stockwell 2019). Historically, the Columbia River supported substantial US commercial, Treaty Tribal, non-treaty, and Canadian First Nations fisheries. Sockeye production drastically declined during the mid to late twentieth century, resulting in sporadic openings of commercial fisheries after 1972, as well as significant reductions to First Nations fisheries for 35 years (Hyatt and Stockwell 2019).

The Okanagan basin Sockeye Salmon include three sub-populations associated with Osoyoos, Skaha, and Okanagan nursery lakes. Osoyoos Sockeye are a Conservation Unit (CU; Holtby and Ciruna 2007) under the Wild Salmon Policy (WSP; DFO 2005). Escapement estimates of Osoyoos Lake Sockeye, obtained using a variety of methods, are available in various sources going back to 1961. Sockeye Salmon were present historically in Skaha and Okanagan lakes (Fryer 1995), but dams erected in the twentieth century prevented access to the spawning grounds above those two lakes. In 2004, the first hatchery-origin Sockeye fry were reintroduced upstream of Skaha Lake from Osoyoos brood stock, and in 2011, the McIntyre Dam below Skaha Lake was modified to allow passage of returning spawners. In 2016, hatchery-origin fry (also from Osoyoos brood stock) were first reintroduced to tributaries of Okanagan Lake (Hyatt et al. 2019), and in years 2020-2021, a small number of returning adults were allowed access to Okanagan Lake; in 2022, 3,000 spawners were given access. Okanagan Lake tributaries have relatively restricted spawning habitat areas (Alex et al. 2020); therefore, Sockeye in Okanagan Lake may be limited by spawning habitat.

In 1999, Hyatt and Rankin generated a preliminary escapement objective for Osoyoos Lake Sockeye of 35,500 using associations between observed spawner abundance and recruitment of in-lake pre-smolts. Since 1997, time series have been gathered for all three lakes including estimates of spawning escapements (Mathieu et al. 2022), total returns attributable to sub-populations of origin for Skaha and Osoyoos and age-at-return^{Footnote 1}, as well as limnological data and Sockeye juvenile estimates (e.g., Hyatt et al. 2017a, 2017b, 2021). In addition, Fisheries and Oceans Canada (DFO), the Province of BC, and the Okanagan Nation Alliance (ONA) have worked collaboratively on a number of key initiatives with the objective of improving overall salmon survival (Hyatt and Stockwell 2019). These projects include a water management system, i.e., Fish Water Management Tools (FWMT), implemented since 2004 (Hyatt et al. 2015; Mathieu et al. 2022), spawning habitat remediation (Carlile et al. 2022) and fish passage improvements.

In 11 of 19 years since 2004, escapements for the Osoyoos population alone have exceeded the overall escapement goal of 35,500. These observations suggest that the current escapement goal is not appropriate.

Fisheries and Oceans Canada (DFO) Fisheries Management Program has requested that Science Branch estimate the biological carrying capacity of the system with respect to smolt production in the nursery lakes and total available adult spawning area in riverine habitats to determine appropriate escapement goals for Okanagan basin Sockeye Salmon in British Columbia. The assessment and advice arising from this Canadian Science Advisory Secretariat (CSAS) Regional Peer Review (RPR) will be used to inform Fisheries Management on the revisions to the harvest management and spawning escapement objectives. Socioeconomic objectives, cultural values, and also potential ecosystem considerations from a future risk assessment (all of which are beyond the scope of this process), will need to be considered in determining the final escapement goals. This assessment will also be used to support bilateral discussions between Canada and the US on a potential harvest sharing agreement for Sockeye Salmon.

Objectives

The following working paper will be reviewed and provide the basis for discussion and advice on the specific objectives outlined below.

Ogden, A.D., K. Alex, G. Pestal. D. McQueen. 2023. Revised Escapement Goals for Sockeye Salmon returning to British Columbia's Okanagan River. CSAP Draft Research Document. Request ID 244.

The specific objectives of this review are to:

1. Determine the status and Limit Reference Points for the Okanagan basin Sockeye sub-populations (together or separately) for fisheries management purposes, if the data support it.
2. Derive Sockeye spawning escapement goal(s) for the Okanagan basin as a whole, based on the results of ^{Footnote 1}.
3. Examine and identify uncertainties in the data and methods, including any relevant ecological and climate change considerations.

Expected Publications

• Science Advisory Report
• Research Document

Expected Participation

• Fisheries and Oceans Canada (DFO) (Science, Fisheries Management)
• Academia (Simon Fraser University, University of British Columbia)
• Governmental Agencies (National Oceanic and Atmospheric Administration, Province of BC Washington Department of Fish and Wildlife)
• Indigenous Organizations (Okanagan Nation Alliance, Syilx First Nation, Columbia River Inter-Tribal Fish Commission, Colville Confederated Tribes)
• Industry (Sport Fish Advisory Committee)
• Non-Governmental Organizations (Pacific Salmon Foundation, Raincoast Conservation Foundation)
• Other invited experts (Douglas County Public Utility District)

References

• Alex, K., Williams, K., and Davis, S. 2020. Okanagan Lake tributaries: prioritization for fish restoration. Prepared for the Colville Confederated Tribes, Okanogan Sub-basin Habitat Improvement Program, by the Okanagan Nation Alliance Fisheries Department.
• Carlile, N., Alex, K., and Eyjolfson, Z. 2022. Redd surveys and drone imagery (Okanagan River Restoration Initiative, ORRI). Prepared for ORRI Steering Committee, Douglas County Public Utility District, by the Okanagan Nation Alliance Fisheries Department.
• DFO. 2005. Canada’s Policy for the Conservation of Wild Pacific Salmon.
• Fryer, J.K. 1995. Columbia Basin Sockeye salmon: causes of their past decline, factors contributing to their present low abundance, and the future outlook (PhD. Thesis,). Univ. of Wash, Seattle, WA.
• Holtby, L.B. and Ciruna, K.A. 2007. Conservation Units for Pacific Salmon under the Wild Salmon Policy. Can. Sci. Advis. Sec. Res. Doc. 2007/070. viii + 350 pp.
• Hyatt, K.D. and Rankin, D.P. 1999. A Habitat Based Evaluation of Okanagan Sockeye Salmon Escapement Objectives. DFO Can. Stock Assess. Sec. Res. Doc. 1999/191.
• Hyatt, K.D., Alexander, C.A.D., and Stockwell, M.M. 2015. A decision support system for improving “fish friendly” flow compliance in the regulated Okanagan Lake and River System of British Columbia. Can. Water Resour. J 40, 87–110.
• Hyatt, K.D., McQueen, D.J., Rankin, D.P., Stockwell, M.M., Wright, H., Lawrence, S., Stevens, A., Mathieu, C., and Wiens, L. 2017a. Methods and summary data for limnology and food-web structure in Skaha Lake, B. C. (2005-2013); revised. Canadian Data Report of Fisheries and Aquatic Sciences 1275.
• Hyatt, K.D., McQueen, D.J., Rankin, D.P., Stockwell, M.M., Wright, H., Lawrence, S., Stevens, A., Mathieu, C., and Weins, L. 2017b. Methods and summary data for limnology and food-web structure in Osoyoos Lake, B. C. (2005-2013); revised. Canadian Data Report of Fisheries and Aquatic Sciences 1274.
• Hyatt, K.D., and Stockwell, M.M. 2019. Chasing an Illusion? Successful restoration of Okanagan River Sockeye Salmon in a sea of uncertainty. In: From Catastrophe to Recovery: Stories of Fish Management Success. AFS Special Publication, p. 65-100.
• Hyatt, K.D., McQueen, D.J., Ogden, A.D., Benson, R., Yaniw, N., Mathieu, C., Stockwell, M.M., Wiens, L., and Wright, H. 2021. Methods, summary data (2014-2017), and errata (2005-2013) for limnology and food web structure in Skaha Lake, B.C. Canadian Data Report of Fisheries and Aquatic Sciences 1327.
• Mathieu, C, Machin, D., Ogden, A., White, T., King, K., Reimer, S., Louie, C., and Alex, K. 2022. Okanagan Fish and Water Management Tools (FWMT) year 2021-2022. Prepared for the FWMT Steering Committee and Douglas County PUD. Prepared by Okanagan Nation Alliance Fisheries Department, Westbank, BC.
• Williams, J.G., Smith, S.G., Fryer, J.K., Scheuerell, M.D., Muir, W.D., Flagg, T.A., Zabel, R.W., Ferguson, J.W., and Casillas, E. 2014. Influence of ocean and freshwater conditions on Columbia River Sockeye Salmon (Oncorhynchus nerka) adult return rates. Fisheries Oceanography 23:210–224.