Monitoring juvenile Chinook salmon outmigration using rotary screw traps on Butte Creek

The California Department of Fish and Wildlife (CDFW) conducts
juvenile salmonid emigration monitoring on Butte Creek at the
Parrot-Phelan Diversion Dam near Chico, California. Monitoring is
conducted annually from October through June utilizing an 8-ft
diameter rotary screw trap (RST) and a diversion screen trap (DST).
Data from this monitoring is used to estimate juvenile spring-run
Chinook salmon (Oncorhynchus tshawytscha) abundance and passage,
identify alevin emergence timing, document juvenile size at
emigration, and document rearing and emigration patterns. This data
will also be used to inform the development of a juvenile production
estimate (JPE) for spring-run Chinook salmon in the Sacramento River
Watershed as required by Condition of Approval 7.5.2 of Incidental
Take Permit No. 2081-2019-006-00 (ITP) issued by CDFW to California
Department of Water Resources (DWR) for the long-term operation of
the State Water Project. Salmonid data collected from the Butte
Creek 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
Sacramento-San Joaquin Delta (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.