This project, managed by the Columbia River Inter-Tribal Fish Commission (CRITFC), seeks to expand knowledge of the factors limiting production of Okanogan and Wenatchee sockeye salmon (Oncorhynchus nerka) stocks.

This contract covers CRITFC’s management and oversight of the following activities:
1. PIT tagging of adult and juvenile sockeye salmon;
2. Collection and analysis of PIT tag detection data for adult and juvenile sockeye salmon (Okanagan basin);
3. Maintenance of, and improvement to, PIT tagging infrastructure as needed in Okanagan Basin (ZSL, OKC, OKM, SKA, and OKP);
4. Acoustic trawl surveys (ATS) and comparison of ATS data data in Lake Wenatchee (Osoyoos/Skaha data is collected by the ONA using other funding);
5. Monthly collection of water chemistry and limnology data in Lake Wenatchee (Osoyoos/Skaha data is collected by the ONA using other funding);
6. Collection of sockeye and/or kokanee juvenile samples in Lake Wenatchee (Osoyoos/Skaha data is collected by the ONA using other funding);
7. Subsequent reporting and data dissemination.

CRITFC subcontracts with multiple governmental partners to complete work elements described in this contract:
Yakama Nation (YN) -- C, D, G
Okanagan Nation Alliance (ONA) -- C, E, F, G, H, I, J, K, L

PROJECT BACKGROUND:
Two stocks of sockeye salmon in the Upper Columbia River Basin are studied in this project: Okanagan and Wenatchee sockeye. Significant PIT tagging infrastructure has been funded and maintained through this project to improve understanding of adult sockeye migration and mortality, including PIT tag antenna arrays at Zosel (ZSL), McIntyre, and Skaha (SKA) dams, as well as an instream arrays at Okanagan Channel (OKC) and Penticton Channel (OKP).  Zosel Dam, located immediately downstream of Osoyoos Lake, is a key site for both the upstream and downstream migration of Okanagan Basin Sockeye Salmon. This project has funded PIT tag detection in fish ladders as well as two floating antennas at the dam. Detection of upstream migrating Sockeye through the ladders is nearly 100%, however in years of high flow, most Sockeye use the spillways and thus pass Zosel Dam undetected. In 2021, additional antennas were installed across the concrete apron in the spill bay downstream of Zosel Dam. It is expected that PIT-tagged Sockeye passing along the river bottom will be detected by these antennas, providing sufficient detections to estimate survival and migration timing in years of high flows.

For Okanagan sockeye, a primary factor affecting the stock is survival upstream of Wells Dam. To quantify mortality, this project has historically funded PIT and acoustic tagging of sockeye salmon at Wells Dam. Additional PIT tagging has occurred at Bonneville Dam as part of CRITFC’s Upstream Migration Timing Accords project (#2009-518-00). Mortality is partitioned by reach upstream of Wells Dam. The intent is to be able to correlate survival with river and lake conditions, hopefully allowing survival to be increased through better Okanagan River management. Additionally, better flow management techniques may optimize adult survival.

This project has continued to PIT tag adults at Wells Dam in order to augment the number of PIT tagged sockeye in the Okanagan Basin used for estimating survival through the established PIT tag network. The PIT tag network developed as part of this project has also improved data on steelhead and Chinook use of the Canadian portion of the Okanagan Basin. Acoustic tagging has also been used to determine survival to the North Basin of Osoyoos Lake, which is a cold-water refuge for migrating sockeye salmon.  Acoustic tagging was discontinued in 2015 due to its expense, and the PIT tag network (largely funded by this project) keeps improving.

For Wenatchee sockeye, this project has sought to standardize smolt abundance estimation methodologies by conducting annual hydroacoustic surveys of Lake Wenatchee. The data from these surveys is compared with Okanagan smolt abundance data collected in Osoyoos and Skaha Lakes. Costs of the Wenatchee acoustic surveys are shared with the DFO, while Osoyoos and Skaha lake surveys are funded by DFO, ONA, and Grant and Chelan PUDs.      

This project also annually supports PIT tagging of juvenile Okanagan sockeye to assess downstream mortality of these fish through the Okanagan River and the Columbia River Basin hydrosystem.  Additional funding for the PIT tagging is provided by the Fish Passage Center through the Comparative Survival Study (CSS), Department of Fisheries and Oceans Canada (DFO), and Grant and Chelan PUDs.