FY 2022 Snohomish River Basin Juvenile Outmigration Monitoring

Installation of the Skykomish and Snoqualmie screw traps took place between January 26th and 28th and full trapping operations commenced on both traps February 3rd. The 2022 season ended on June 23rd on the Skykomish trap the sampling season on the Snoqualmie trap ended June 22nd. A total of 22 scheduled sampling shifts were cancelled due to unfavorable sampling conditions (i.e. high debris and discharge levels). As a result,

the Snoqualmie trap was operated for approximately 913 hours from Statistical Week (SW) 6 - 26. Of those hours, 535 hours were fished at night, representing 59% of total trapping effort. On the Snoqualmie trap 13,474 salmon and trout were captured, counted and released on the Snoqualmie trap. Captured unmarked Chinook included 179 sub-yearlings and 1 yearlings. Catch per unit effort (fish/hour) of unmarked Chinook (0.20); project average CPUE is 0.65 (2001-2021). Project average catch of sub -yearling Chinook is 536. Captured unmarked Coho included 473 yearling and 393 sub-yearlings. Catch per unit effort of unmarked Coho (0.52); project average is 1.28. Project average catch of Coho yearlings is 1,023 fish. During the trapping and handling process a total of 22 salmonid mortalities were reported, some of which were killed for toxicology screening.

The Skykomish trap was operated for approximately 925 hours over a 20-week period from Statistical Week (SW) 6 to 26. Of those hours, 550 were fished at night representing 59% of total trapping effort. On the Skykomish trap a total of 216,778 salmon and trout were captured, counted, and released. Captured unmarked chinook included 1,652 sub-yearlings (0+) and 17 yearlings (1+). Unmarked Chinook sub-yearlings 2004-2022 average: 2061. Captured unmarked Coho included 1,446 sub-yearlings and 2,879 yearlings. Unmarked Coho yearlings 2004-2022 average: 3,567. During the trapping and handling process a total of 49 salmonid mortalities were reported, of which 9 were unmarked Chinook

Unspent FY20 funds were carried over to fund trap operations in 2022. FY20 PCSRF funds were utilized to pay staff on the smolt traps until the beginning of April 2022.

Overlapping PCSRF project timelines occur due to the fact that we use several funding sources to operate the screw traps. The application and award announcements for these grants operate on different schedules. When we apply for the PCSRF funds we have to assume we will not receive these additional funds since they are competitive grants. More funds were rolled over than usual due to the shutdown of the smolt traps on March 14th 2020 due to the pandemic and the smaller crew used in 2021 to ensure social distancing.

In May of 1999, the National Marine Fisheries Service (NMFS) listed the Puget Sound Chinook salmon as threatened under the federal Endangered Species Act (ESA). This listing included Chinook salmon from the Snohomish River Basin (Skykomish and Snoqualmie populations). The recovery of these species depends upon improving the effectiveness of habitat, harvest, and hatchery management across the basin. In order to achieve such improved effectiveness, additional information is necessary to fill important data gaps within the Snohomish system and to assess impacts of restoration efforts, including information on Chinook and Coho salmon abundance, productivity, spatial structure, and diversity (Snohomish Basin Salmonid Recovery Technical Committee, 2005) (. Information about the trends and inter-annual variability in these population parameters is critical to inform salmon recovery efforts, provides basic information on the productivity and capacity of the system, and can lead to significant improvements in harvest management modeling and run forecasting. Additionally, the monitoring of production and survival along with other physical, chemical, and biological conditions provides a means to evaluate recovery actions, habitat conditions, and potential ecological trajectories in the basin.



A key component to provide information on Snohomish salmon populations is the operation of two rotary screw traps in the Skykomish and Snoqualmie rivers. These projects involved trapping and enumerating juvenile Chinook and Coho salmon (as well as several un-targeted species) as they emigrate from the Snohomish River Basin to the Puget Sound. The goals of these trapping efforts are to estimate Chinook and Coho salmon natural production, migration patterns, and freshwater survival. The goal of this project is to track Chinook and coho production and survival information and migration timing within the Snohomish river basin, which can be used in part to evaluate salmon recovery efforts in the various portions of the watershed, to refine preseason run size forecasting by harvest managers, and used in combination with other monitoring and research efforts to better understand and identify priority restoration areas. These goals are accomplished through the direct quantification of juvenile salmon emigrations, evaluation of trap efficiency, and assessment of influential environmental attributes.