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, 2008–2009 |
| Author: | Miller, J. D., D. L. Burwen, and S. J. Fleischman |
| Year: | 2012 |
| Report ID: | Alaska Department of Fish and Game, Fishery Data Series No. 12-73, Anchorage |
| Abstract: | Chinook salmon (Oncorhynchus tshawytscha) passage in the Kenai River in 2008 and 2009 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 2008, the sonar project operated 16 May through 3 August. The standard estimate of total upstream passage of Chinook salmon in 2008, based on target strength and range thresholds, was 46,294 (SE 528) fish: 15,355 (SE 296) during the early run (16 May–30 June) and 30,939 (SE 438) during the late run (1 July–3 August 2008). Total (expanded for missing days) late-run passage estimated for 1 July through 10 August was 34,641 fish (SE 1,682). In 2009, the sonar project operated 16 May through 4 August. The standard estimate of total upstream passage of Chinook salmon in 2009, based on target strength and range thresholds, was 37,022 (SE 512) fish: 11,334 (SE 263) during the early run and 25,688 (SE 440) during the late run. 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 for both years are too high. Tests of long-range Dual-frequency Identification Sonar (DIDSON) continued in the Kenai River in 2008 and 2009. DIDSON exhibited many advantages over split-beam sonar with respect to target detection, target tracking, and species classification, confirming its potential as a tool for inseason monitoring of Chinook salmon run strength |
| Keywords: | split-beam sonar, DIDSON, Chinook salmon, Oncorhynchus tshawytscha, acoustic assessment, Kenai River, riverine sonar, early run, late run |