Science activity

These monitoring efforts can provide critical information on juvenile salmonid distribution and survival, which inform biologists and managers interpretations of the exposure and intensity of CVP and SWP water operation risks on tagged populations in Central Valley rivers and the Bay- Delta. Understanding salmon survival and migration dynamics in the Delta and its tributaries is critical to the recovery of ESA-listed species, and sport and commercial fisheries management. For example, estimating the population size of endangered Sacramento River Winter-run Chinook (SRWRC) as they enter and exit the Delta is considered critical for informing Delta water management actions (Interagency Ecological Program (IEP) SAG 2013). “The use of realtime acoustic receivers that immediately transmit acoustic tagged (AT) fish detections needs to be included in the expanded network” (Johnson et al., in press). Tracking the fate of individual tagged fish will be accomplished with AT and used to develop estimates of survival and movement for other non-AT fish also part of that group. Population level sampling programs will use survival estimates generated by AT and applied to other mass marked (coded wire tagging) groups to develop improved capture efficiency for these sampling programs. Objectives: • Deploy and service field monitoring acoustic telemetry stations at locations important to fish and water management. • Implant, transport, and release acoustically tagged juvenile ESA-listed wild and hatchery juvenile salmonids. • Analysis and synthesis to support production and development of new metrics for understanding the survival, distribution, and entrainment of juvenile salmonid along the Sacramento River and its floodways, as well as, the Bay-Delta. Six-Year Steelhead Study Continuation Reclamation’s Proposed Action for ROC on LTO Section 4.10.5.12.3 Additional Measures includes a San Joaquin Basin Steelhead Telemetry Study -- Continuation of the 6-Year Steelhead telemetry study for the migration and survival of San Joaquin Origin Central Valley Steelhead. This investigation involves undertaking experiments utilizing acoustically-tagged salmonids to confirm proportional causes of mortality due to flows, exports, and other project and non-project adverse effects on steelhead smelt out-migrating from the San Joaquin Basin and through the southern Delta. This study is to coincide with different periods of operations and focus on clipped hatchery steelhead (Oncorhynchus mykiss). The period of interest is between February 15 and June 15, which coincides with a majority of O. mykiss outmigration from the Stanislaus River and recoveries of steelhead smolts in the Mossdale fish monitoring efforts. This period is to include changes in CVP/SWP operations that include reductions in exports, reductions in reverse flows in Old and Middle rivers (OMR), and San Joaquin River pulse flows to assess the influence of flow and exports on juvenile steelhead survival. This study is designed to evaluate juvenile steelhead route selection at channel divergences in the south Delta and along the mainstem San Joaquin River, and how these behaviors influence survival in specific reaches and through the Delta to Chipps Island.