Lummi Nation Nooksack River Basin Salmonid Population Assessments, FY17

A lower river smolt trap and spawner surveys in the South and Middle Forks of the Nooksack River was 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. Smolt trap mark/recapture calibration trials were used and validated with beach seine sampling at the trap site to improve smolt production estimates. Production estimates were made for Chinook, steelhead, coho and other salmonids from modeled expansion of trap catches.

River water temperature, turbidity, discharge, and stage height were monitored to help interpret survey results and to assist with field scheduling. Spawner survey data were shared with other co-managers to develop Chinook escapement estimates using a traditional approach based on visual redd and fish counts. The predator observations occurred concurrent with smolt trap operations.

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.