Lummi Nation Nooksack River Basin Salmonid Population Assessments, FY19

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. Fishery 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 was conducted to improve smolt production estimates and sample a wider spectrum of outmigrant size classes. Production estimates are in progress to be made for Chinook, Steelhead, Coho and other salmonids from modeled expansion of trap catches based on catch efficiency.


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 were 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 counts (ongoing as of 2021 due to Covid-related delays in processing of genetic stock identification). New genetic mark-recapture escapement techniques using DNA data collected from spawner carcasses and trap outmigrants will be compared with methods that rely on visual counts.


For both efforts, fish lengths and analysis of scales, otoliths, and DNA tissue samples provides 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 was 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.

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 develop a life history model and framework for Nooksack 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.