Coho Stock Monitoring and Evaluation 2023

The Nez Perce Tribe is implementing a phased approach to coho salmon reintroductions in the Clearwater River subbasin and partially in the Snake River Basin (Lostine River). The Nez Perce Tribe’s overall goal for coho salmon is to reintroduce and restore coho salmon to levels of abundance and productivity sufficient to support sustainable runs and annual Tribal harvest. Consistent with the Clearwater Subbasin Plan (EcoVista 2003), the Nez Perce Tribe (NPT) envisions an annual escapement of 14,000 coho to the Clearwater River Subbasin, with additional fish (7,000) in the Snake River Basin. The coho reintroduction program focuses on the establishment of a localized coho salmon stock capable of enduring the migration to the back to areas where they were released. Accompanying that goal is a desire to monitor and evaluate the results of the coho salmon restoration program so that operations can be managed to optimize hatchery and natural production and minimize deleterious ecological impacts. Pursuant to this informed adaptive management approach, research data collection and analysis for the coho restoration M&E program endeavors to 1) provide science-based recommendations for management and policy consideration; 2) evaluate coho abundances relative to the reintroduction restoration goals (annual escapement of 14,000 coho to the Clearwater River Subbasin) and 3) assist in the reestablishment of tribal and recreational fisheries.

A base level of hatchery-origin coho monitoring and evaluation has been started with Mitchell

Act Grant funding and until recently with some limited Pacific Coastal Salmon Recovery Funds. Evaluations will occur at the release from each hatchery (individual hatchery release performance), release location (individual and total aggregate released at each location), and adults returning to the basin and stream to include:

1) Estimate adult returns of abundance and distribution (adult escapement and distribution, redd surveys, hatchery broodstock, PIT tag detections) to Bonneville Dam, Lower Granite Dam, and upstream tributaries.

2) Estimate juvenile migration and survival metrics (to and through the Snake and Columbia River hydrosystem.

3) Estimate contributions to ocean, Columbia mainstem, and tributary fisheries.

4) Estimate productivity measures of smolt-to-adult survival, recruit per spawner, an adult-to-adult return rates.

5) In-hatchery production survival and growth monitoring.

6) Provide pre- and in-season adult run forecasting.



Monitoring activities will occur at 7 distinct worksites: Dworshak National Fish Hatchery (DNFH) rearing facility, Eagle Creek National Fish Hatchery (ECNFH), Clear Creek/Kooskia National Fish Hatchery, Lapwai Creek, Lostine River/Cascade Salmon Hatchery, Clearwater Basin, and Lower Granite Dam. Specific proposed activities at each worksite are described in the attached project proposal and reflected in the proposed metrics.

The benefit or the program is that coho salmon will restored to sufficient numbers in the Snake river basin to support natural production, as well as tribal and non-tribal harvest. This level of production would provide for the Clearwater broodstock to be naturally, self-sustaining and to provide a run sustaining hatchery supplementation. Our long-term adult return goal for the Snake River is 21,000 coho salmon, breaking it down to 14,000 returning to the Clearwater River and 7,000 to the Lostine River in Oregon. This program with require a substantial hatchery production component and the establishment of highly productive naturally spawning coho salmon to become self-sustaining.