Where Did They All Go? A Deconstruction of the Record 2012 Columbia Basin Sockeye Run

                The 2012 sockeye salmon return past Bonneville Dam of 515,673 far exceeded the sockeye return in any other year since the dam was constructed in 1938.   Yet this record run resulted in an estimated spawning escapement of fewer than 110,000 sockeye.  A record combined sport and tribal harvest of 162,000 fish leaves over 200,000 sockeye missing somewhere on the upstream migration.  By using fish counts at mainstem dams, along with data from the nearly 3000 Columbia Basin sockeye we PIT tagged and 60 sockeye we acoustic tagged in 2012, it is possible to partition these missing fish over their 800+ km migration corridor.  In addition, the tag data suggests a smaller run and a larger escapement, reducing the number of missing fish.  PIT and acoustic tag data suggests that most of these fish disappeared in terminal areas as well as between Bonneville and McNary dams.