This project seeks to expand our knowledge on the factors limiting production of Okanogan and Wenatchee sockeye salmon stocks.  A primary factor affecting the Okanogan stock is believed to be survival upstream of Wells Dam.  To quantify this mortality, in 2009 this project funded PIT tag detection antennas at Vertical Diversion Structure 3 upstream of Osoyoos Lake and in 2010 will fund installation of PIT tag detection at Zosel Dam fishways.  In addition, an acoustic tag antenna network will continue to be developed upstream of Wells Dam.  Sockeye will be PIT tagged at the Bonneville Dam adult fish facility (as part of another MOA project, Upstream Migration Timing) as well as at the Wells Dam east bank fish trap.  Sockeye will also be acoustic tagged at Wells Dam.  Between the acoustic and PIT tags, Okanogan sockeye salmon mortality will be partitioned by reach upstream of Wells Dam and we hope to then be able to correlate survival with river and lake conditions, hopefully allowing survival to be increased through better Okanagan River management.  

This project will also standardize smolt abundance estimation methodologies between the two stocks by conducting annual hydroacoustic surveys of Lake Wenatchee to compare with those being conducted in Osoyoos Lake.  Given that the strength of the Wenatchee run relative to the Okanogan run has greatly declined in recent years, a plan for further Wenatchee sockeye research will be developed.

This project will expand our Upstream Migration Studies project (2008-518-00) by funding deployment of PIT tag detection antennas as well as an acoustic tag network in the Okanagan Basin.  This will allow sockeye salmon to be tracked through the Okanogan Basin, thereby allowing us to extend our migration survival estimates into the Okanogan River.  We also will be able to determine where in the Okanogan River-Osoyoos Lake mortality is occurring, which may then allow for the development of different river management actions to reduce this mortality.  It is hoped that, depending on where mortality is occurred, better flow management techniques to optimize adult survival can be developed.  The PIT tag network we develop as part of this project may also improve data on steelhead and Chinook use of the Canadian portion of the Okanogan Basin.