McEwen, 2007

McEwen, M. S. 2007. Sonar estimation of chum salmon passage in the Aniak river, 2005. Alaska Department of Fish and Game, Fishery Data Series No. 07-86, Anchorage, Alaska.

The Aniak River sonar project has provided daily fish passage estimates for most years since 1980. During this time, the project has undergone important modifications, including changing from the original Bendix sonar to dualbeam in 1996 and to a high frequency imaging sonar (DIDSON) in 2004. In 2005, the project maintained the sampling schedule adopted in 2003 in which the sonar operated for three 4-hour blocks each day (0000–0400, 0800–1200, and 1600–2000 hours). The Aniak River sonar project was operational from June 23 through July 31, 2005. During this period, an estimated 1,171,977 fish (SE 28,821) passed through the ensonified area, the majority of which are assumed to be chum salmon Oncorhynchus keta. The peak passage of 76,652 fish occurred on July 14 and the 50% passage date occurred on July 15. Age-0.2, -0.3, and -0.4 chum salmon comprised 5.4%, 89.5% and 5.0% of the escapement estimate, respectively.