2020 RED BLUFF DIVERSION DAM ROTARY TRAP JUVENILE ANADROMOUS FISH ABUNDANCE ESTIMATES

Rotary-screw trap (RST) sampling was suspended from 3/25/2020 through 6/30/2020 in order to protect employee health and safety during the Coronavirus (COVID-19) global pandemic. During that time, traps were removed from the river. Just prior to resuming sampling operations, four new 1.5-m diameter and one 2.4-m diameter RSTs were installed across a transect downstream of Red Bluff Diversion Dam (RBDD) on the Sacramento River in Northern California. This new five-trap configuration provides a solution to sampling a location that has become shallower since the RBDD gates were permanently placed in the raised position. The non-sampled period impacted brood year (BY) 2020 late-fall Chinook Salmon Oncorhynchus tshawytscha passage estimates and abundance indices for steelhead/Rainbow Trout O. mykiss and Green Sturgeon Acipenser medirostris. No interpolation for missed samples was performed during this extended break in sampling; therefore, the data should be viewed cautiously and not used for interannual comparisons.