Largely supported by the Interagency Ecological Program (IEP), California Department of Water Resources (DWR) has operated a fisheries monitoring program in the Yolo Bypass, a seasonal floodplain and tidal slough, since 1998. The objectives of the Yolo Bypass Fish Monitoring Program (YBFMP) are to: (1) collect baseline data on lower trophic levels (phytoplankton, zooplankton, and aquatic insects), juvenile fish and adult fish, hydrology, and water quality parameters; 2) investigation of the temporal and seasonal patterns in chlorophyll-a concentrations, including whether high concentrations are exported from the Bypass during agricultural and natural flow events and the possibility of manipulating bypass flows to benefit listed species like Delta Smelt (Hypomesus transpacificus) and Chinook salmon (Oncorhynchus tshawytscha). The YBFMP operates a rotary screw trap and fyke trap, and conducts biweekly beach seine and lower trophic surveys in addition to maintaining water quality instrumentation in the bypass. The YBFMP serves to fill information gaps regarding environmental conditions in the bypass that trigger migrations and enhanced survival and growth of native fishes, as well as provide data for IEP synthesis efforts. YBFMP staff also conduct analyses of our monitoring data to address pertinent management related questions as identified by IEP. The Yolo Bypass has been identified as a high restoration priority by the National Marine Fisheries Service and US Fish and Wildlife Service Biological Opinions for Delta Smelt, Winter and Spring-run Chinook salmon and by California EcoRestore. The YBFMP informs the restoration actions that are mandated or recommended in these plans, and provides critical baseline data on the ecology of the bypass and how it interacts with the broader San Francisco Estuary. Only juvenile and adult fish catch with associated water quality are presented in this dataset.