Lummi Nation Nooksack River Basin Salmonid Population Assessment, FY16

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.
Field staff also conducted 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. New genetic mark-recapture escapement techniques using DNA data collected from spawner carcasses and 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 was included in this proposal. These projects included a significant analysis component where professional staff utilized 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 were resources permitted. Environmental monitoring of sea surface temperature (SST), salinity and dissolved oxygen (DO) helped us to interpret the catch data. Monitoring presence of predator, competitor, and prey species in the catch was used to 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.

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.