Lummi Nation FY20 Nooksack River Basin Salmonid Population Assessments

A lower river smolt trap and spawner surveys in the South and Middle Forks of the Nooksack River were used to monitor salmonid populations in the Nooksack River Basin. Fisheries biologists and technicians operated a rotary screw smolt trap at the upper limit of the tidal influence in the lower river mainstem during the principal outmigration period from January to August. Additional beach seine sampling near the trap site were conducted to improve smolt production estimates and sample a wider spectrum of outmigrant size classes. Our goal through the combination of these sampling methods is to maximize the collection of DNA tissues via fin clips from ESA-listed Chinook to identify life history origin. Production estimates were made for Chinook, Steelhead, Coho and other salmonids from modeled expansion of trap catches.



Field staff participated in co-manager spawning ground surveys in South and Middle Forks of the Nooksack River with emphasis on Chinook salmon. River water temperature, turbidity, discharge, and stage height are monitored to help interpret survey results and to assist with field scheduling. Spawner survey data was shared with other co-managers to develop Chinook escapement estimates using a traditional approach based on visual redd and fish carcass counts. Ongoing genetic mark-recapture escapement techniques using DNA data collected from spawner carcasses and smolt trap outmigrants were compared with methods that rely on visual counts.



For both projects, fish lengths and analysis of scales, otoliths, and DNA tissue samples provided information on age, stock composition, and life history types needed for refinements in adult escapement and smolt production estimates. Field staff time to collect this information is included in this proposal. Professional staff will utilize data collected from the monitoring element of the project and other independent data sources to increase the precision and accuracy of models used to develop adult escapement and smolt production estimates.



To supplement data needed for production and escapement estimates, additional beach seine sampling was used in the river, estuary, and adjacent nearshore areas as resources permit. In coordination with a separate grant-funded project, environmental monitoring of sea surface temperature (SST), salinity and dissolved oxygen (DO) will help us to interpret the catch data and possibly link these data to climate change factors. Monitoring presence of predator, competitor, and prey species in the catch may provide insight into factors affecting migratory timing, life-history types present, rearing densities, habitat utilization, and co-occurrence of stocks from the Nooksack and other watersheds.



In 2021, LNR also deployed a second smolt trap in the South Fork Nooksack River in Acme, WA. This work is separately funded but will employ methods and sampling similar to the lower mainstem smolt trap work and overlap with potential analyses and reporting.



Actual Start Date was revised to reflect the transition from the FY2019 Award to the FY2020 Award with both projects conducting the same scope of work. The last FY 2019 expense was on 6/12/2021 and the first FY 2020 expense occurred on 5/15/2021.

The goal of this project is to improve the quality and accuracy of salmonid escapement, production, and habitat use with a focus on Chinook. A secondary goal is to identify constraints preventing recovery of the stocks. This work is to evaluate and adaptively improve methods for salmonid population baseline data acquisition and estimates required for: 1) ESU reporting, 2) forecasting/management, 3) stock identification and aging, 4) evaluation of survival, restoration, and hatcheries, 5) other research including impacts of climate change or identifying limiting factors. A secondary objective is to utilize these data in a life history model and framework for Nooksack early Chinook.



The expected benefits of providing more accurate and complete population estimates and habitat use for adults and juveniles are: 1) evaluation and identification of restoration activities that will have or could have the largest impact on recovery, 2) improved ability to identify factors limiting recovery, such as predation or toxicity that habitat restoration cannot address and that may require other actions or solutions.