Fisheries, Subsistence, and Habitat
Publications Searchable Database
Search Again| Division: | Sport Fish |
| Title: | Estimates of Chinook salmon passage in the Kenai River using split-beam sonar, 2007. |
| Author: | Miller, J. D., D. L. Burwen and S. J. Fleischman |
| Year: | 2011 |
| Report ID: | Alaska Department of Fish and Game, Fishery Data Series No. 11-52 Anchorage. |
| Abstract: | Chinook salmon (Oncorhynchus tshawytscha) passage in the Kenai River in 2007 was estimated using split-beam sonar technology. Early (16 May–30 June) and late (1 July–10 August) runs of Kenai River Chinook salmon have been monitored acoustically since 1987. A 200 kHz split-beam sonar system has been used since 1995 to estimate numbers of adult Chinook salmon migrating into the Kenai River. From 1987 to 1994, a 420 kHz dual-beam sonar was used to generate similar estimates. In 2007, the sonar project operated 20 May through 4 August. The standard estimate of total upstream passage of Chinook salmon, based on target strength and range thresholds, was 58,883 (SE = 741) fish: 15,904 (SE = 285) during the early run (20 May–30 June 2007) and 42,979 (SE = 684) during the late run (1 July–4 August 2007). Total (expanded for missing days) early-run passage estimated for 16 May to 30 June was 16,217 (SE = 403) fish. The standard errors associated with these estimates reflect only sampling error and no other sources of uncertainty (such as target detection, species composition, direction of travel, and target tracking). Comparisons with alternative estimators of abundance suggest that the standard estimates are too high. Long-range Dual-frequency Identification Sonar (DIDSON) was tested in 2007 and found to provide sufficient resolution to estimate fish length at ranges up to 21 m, and to estimate species composition of passing fish. |
| Keywords: | split-beam sonar, DIDSON, Chinook salmon, Oncorhynchus tshawytscha, acoustic assessment, Kenai River, riverine sonar, early run, late run |