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US Fish & Wildlife Service FieldNotes

STOCKTON  FWO:  Conducting Juvenile Fall-run Chinook Salmon Survival and Migration Pilot Study in the San Joaquin River Helps Determine Best Management Actions

Region 8, April 1, 2011
Michelle Workman, USFWS fish biologist, implants a juvenile Chinook salmon with an acoustic tag.
Michelle Workman, USFWS fish biologist, implants a juvenile Chinook salmon with an acoustic tag. - Photo Credit: n/a

By Michelle Workman

The San Joaquin River Restoration Program (SJRRP) Fisheries Management Plan sets Chinook salmon population goals needed to successfully achieve the Restoration Goal as described in the San Joaquin River Settlement Agreement.

With these population goals in mind, the San Joaquin River Restoration Program conducted a pilot study utilizing acoustic telemetry to identify and characterize three possible limiting factors (predation, entrainment, and physical habitat) for juvenile Chinook survival as they move through the San Joaquin River Restoration Area. Additional knowledge of these possible limiting factors will help the SJRR Program determine the best approach for: 1) reintroduction efforts, 2) developing habitat enhancement projects, and 3) prioritizing actions for the reduction or elimination of predation, entrainment and habitat impacts to fish survival.

The pilot study began in April with approximately 1,200 juvenile fall run Chinook salmon obtained from the DFG Feather River Hatchery. In order to track the movements of the released fish, they were tagged and stationary telemetry receivers deployed within the Restoration Area from Friant Dam to the Merced River confluence.

The fish were released at two different locations – below Friant Dam (river mile 266) and at the San Mateo Crossing (river mile 212). Of the 192 fish released with acoustic transmitters, 71 were detected at the end of the Restoration Area at the Hills Ferry Barrier.

A Field Advisory with more details about the study is available on the SJRRP website at www.restoresjr.net/activities/field/index.html, and a preliminary report from this first effort of acoustic tracking of juvenile Chinook salmon was posted on the SJRRP website in July at www.restoresjr.net/flows/Fisheries.html. A final report on this study will be included in the SJRRP Annual Technical Report (ATR) scheduled to be released in early 2012.

The telemetry study will be continued in 2012 to analyze the movement of Chinook salmon in different water year types. Some conclusions from the preliminary report include relocating some receivers to improve fish detection and using additional receivers between the Mendota Pool and Sand Slough.

Contact Info: Ramon Martin, 209-334-2968 ext. 401, ramon_martin@fws.gov