Lummi Nation Nooksack River Basin Salmonid Population Assessments, FY18

The three types of data collections included in this project are: 1) adult spawner data from spawning ground surveys (SGS), 2) juvenile outmigrants from the rotary screw trap (RST) in the lower river, and 3) beach seining executed at the trap site as well as upriver sites between Ferndale and Nugent’s Corner. The tables in the final progress report lists the SGS and RST results from this reporting period, including counts of salmonids by species obtained, samples collected, as well as survey distances. This was the second year of expected significant returns from the Skookum South Fork spring (late run) Chinook integrated hatchery program. The total carcasses sampled over the past two years reflects the apparent initial success of that program; over twice as many carcasses were sampled in 2017 from recent years.

Field staff participated in co-manager spawning ground surveys focused in the Mainstem, South, and Middle Forks (and one in the North Fork) 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 were shared with other co-managers to develop Chinook escapement estimates using a traditional approach based on visual redd and fish counts.

For the spawning ground surveys, a pre-season meeting was held with co-managers (WDFW and Nooksack Tribe) emphasizing the need to achieve a balanced survey design with equal effort for counting and sampling carcasses in all of the river sections where Chinook spawn. Also emphasized was the need to make sure everyone was collecting the same critical information, required to improve our expansion or estimation of the population. Critical information includes visibility or survey condition codes, and estimating the percent of the live or dead fish counted. Although we were not successful in achieving a balanced design, there was improvement in the collection of the condition parameters. The percentage of time sampled was maintained at approximately 40% and all diurnal periods were sampled equally. The potential population bias from previous sampling years has not yet been estimated.

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.