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US Fish & Wildlife Service FieldNotes
STOCKTON FWO: Salmon Survival Study Using Acoustic Methodology
Region 8, January 17, 2009
Arnold Ammann of National Marine Fisheries Service surgically implants juvenile salmon with VEMCO acoustic tag. (photo: Phil Voong, USFWS)
Arnold Ammann of National Marine Fisheries Service surgically implants juvenile salmon with VEMCO acoustic tag. (photo: Phil Voong, USFWS) - Photo Credit: n/a
Juvenile late-fall Chinook salmon with incision and suture associated with tag implantation. (photo: Phil Voong, USFWS)
Juvenile late-fall Chinook salmon with incision and suture associated with tag implantation. (photo: Phil Voong, USFWS) - Photo Credit: n/a
Juvenile late-fall Chinook salmon being interogated for acoustic tag code prior to release. (photo: Phil Voong, USFWS)
Juvenile late-fall Chinook salmon being interogated for acoustic tag code prior to release. (photo: Phil Voong, USFWS) - Photo Credit: n/a
VEMCO VR100 receiver detects acoustic tag code from juvenile Chinook salmon prior to release. (photo: Phil Voong, USFWS)
VEMCO VR100 receiver detects acoustic tag code from juvenile Chinook salmon prior to release. (photo: Phil Voong, USFWS) - Photo Credit: n/a
Paired containers of juvenile Chinook salmon being held prior to release for USFWS and USGS survival studies in the Sacramento-San Joaquin Delta. (photo: Phil Voong, USFWS) 
Paired containers of juvenile Chinook salmon being held prior to release for USFWS and USGS survival studies in the Sacramento-San Joaquin Delta. (photo: Phil Voong, USFWS)  - Photo Credit: n/a

by Pat Brandes, Stockton FWO
In November 2008 and January 2009, the Stockton Fish and Wildlife office released juvenile salmon implanted with VEMCO hydroacoustic transmitter tags as part of a study to estimate the survival of juvenile salmon migrating through the Sacramento-San Joaquin Delta. One set of  fish releases was made when the Delta Cross Channel (DCC) gates were open and a second set of fish releases was made when the DCC was closed.  This is the third year of the study using VEMCO acoustic tags and receivers.  Previous mark and recapture studies have indicated that survival for juvenile salmon that enter the interior Delta is lower than survival for salmon that stay on the main stem Sacramento River (Newman, 2008).  Closing the DCC has been used in the past as a protective measure to increase the survival of listed winter-run salmon through the Delta by reducing the proportion of salmon that enter the interior Delta. However, it has not been clear in these previous studies, what proportion of the juvenile salmon migrating downstream toward the ocean enter the interior Delta through the DCC. Acoustic receivers deployed through-out the Delta and near the DCC will allow estimates of the proportion diverted into the interior Delta to be estimated for each of the study years. The Fish and Wildlife  Service was able to leverage funding by partnering with others for the installation and maintenance of the receiver array (UC Davis), tagging the fish and maintaining the database (National Marine Fisheries Service’s Southwest Fisheries Science Center); and analyzing and modeling the data (CALFED Bay-Delta Program’s Pre-Doctoral Fellow, Russ Perry from University of Washington). In addition, Coleman National Fish Hatchery provided the juvenile late-fall Chinook salmon used in the study.  A manuscript on the results of the first year’s study has been conditionally accepted by the North American Journal of Fisheries Management.

This year’s study was unique because the tagged salmon were released in conjunction with other acoustically-tagged salmon from a larger, but similar, study conducted by U.S. Geological Survey (USGS).  The USGS study used a different type of acoustic tag and receiver (Hydroacoustic Technology, Inc.), along with other instrumentation to understand how the water currents at delta waterway junctions affect the proportion of juvenile salmon migrating into channels through-out the Delta, in addition to estimating juvenile salmon survival under different DCC gate conditions.  Tagged salmon were released on the Sacramento River near downtown Sacramento and into Georgiana Slough with the DCC gates open in November and with the DCC gates closed in January.  By releasing the tagged salmon from both studies at the same time survival estimates can be directly compared.  In addition the assumptions associated with tag-life can be evaluated by comparing the results of the two studies.

 

Newman K.B. 2008. “An evaluation of four Sacramento-San Joaquin River Delta juvenile salmon survival studies.”, 3/31/08.  Available at http://www.delta.dfg.ca.gov/jfmp/datareports.asp

Contact Info: Pat Brandes, 209-946-6400 X 308, Pat_Brandes@fws.gov