Monitoring juvenile Chinook salmon outmigration using rotary screw traps on the Lower Feather River

CDFW issued Incidental Take Permit No. 2081-2019-006-00 (ITP) to the
California Department of Water Resources (DWR) on March 31, 2020,
for the long-term operation of the State Water Project (SWP) in the
Sacramento San Joaquin Delta (Delta). Condition 7.5.2 of the ITP
requires the development and establishment of a spring-run Chinook
salmon (Oncorhynchus tshawytscha) juvenile production estimate (JPE)
to increase understanding of the impacts that water operations have
on the spring-run Chinook salmon population in the Sacramento River
watershed and to inform the development of minimization measures to
reduce take of spring-run Chinook salmon at Delta fish salvage
facilities.  

As a part of the JPE effort, CDFW began operating a new rotary screw
trap (RST) monitoring station on the lower Feather River near River
Mile 17, approximately 1 mile downstream of Star Bend Park and Boat
Ramp near Olivehurst, in January 2022. This RST location represents
the lowest point in the Feather River Watershed where juvenile
salmon are sampled with an RST prior to entering the Sacramento
River and includes salmon emigrating from the Yuba River. The
expanded juvenile monitoring effort will help resource agencies and
water managers identify numbers of salmon emigrating from the
Feather River Watershed and contributing to the spring-run Chinook
salmon population entering the Delta.

Monitoring is conducted annually from October through June utilizing
a pair of eight-foot rotary screw traps (RST). Data collected at the
Lower Feather River RST site provides information on the temporal
distribution, relative abundance, and race composition of juvenile
Chinook salmon; and temporal distribution and relative abundance of
steelhead trout (O. mykiss) emigrating from the Feather River and
tributaries, including the Yuba River, to the Delta. Salmonid data
collected from the Lower Feather River RST, among other datasets, is
also used by the Salmon Monitoring Team (SaMT) to understand the
movement of juvenile salmon in the Sacramento River Watershed to
estimate the number of winter-run and spring-run Chinook salmon that
have entered the Delta. SaMT is a real-time operations monitoring
team required by Condition of Approval 8.1.2 of the ITP which meets
weekly from October through June, to provide advice for real-time
management of SWP operations to DWR, CDFW, and the Water Operation
Management Team (WOMT) to minimize take of winter-run and spring-run
Chinook salmon in the Delta.

Note: data within the current year’s monitoring season are
considered provisional.