Chinook Salmon Escapement In The Gulkana River 2007 2008 PDF Download

Counting tower techniques were used to estimate Chinook salmon Oncorhynchus tshawytscha escapement in the Gulkana River during 2016, 2017, and 2018. The counting tower was located in the mainstem Gulkana River about 3.25 rkm upstream of the West Fork Gulkana River confluence. The estimated escapement of Chinook salmon was 1,122 (SE = 166; 95% CI = 796-1,447) in 2016, 3,336 (SE = 309; 95% CI = 2,730-3,942) in 2017, and 5,174 (SE = 344; 95% CI = 4,499-5,848) in 2018. These numbers do not represent total inriver escapement, just passage above the counting tower site. The 2016 estimated escapement of Chinook salmon was the lowest since the inception of the project in 2002, whereas the 2018 estimated escapement was the 2nd highest on record and had the latest run timing. The dates of 25th, 50th, and 75th percentile passage of Chinook salmon have been getting later since the project's inception in 2002. The estimated escapement of sockeye salmon O. nerka during the counting tower's operational period was 26,010 (SE = 1,157; 95% CI = 23,743-28,277) in 2016, 20,492 (SE = 927; 95% CI = 18,675-22,309) in 2017, and 12,436 (SE = 540; 95% CI = 11,377-13,494) in 2018. The partial sockeye salmon escapement estimate in 2018 was the 2nd lowest since the inception of this project in 2002.