Fisheries, Subsistence, and Habitat
Publications Searchable Database
Search Again| Division: | Sport Fish |
| Title: | Anchor River 2003 and 2004 Chinook salmon and 2004 coho salmon escapement |
| Author: | Kerkvliet, C. M., D. L. Burwen, and R. N. Begich |
| Year: | 2008 |
| Report ID: | Alaska Department of Fish and Game, Fishery Data Series 08-06, Anchorage |
| Abstract: | A decline during the 1990s in aerial counts of the Chinook salmon Oncorhynchus tshawytscha escapements at the Anchor River, Alaska created concern about overexploitation of this stock. In 2001, this apparent decline prompted the Alaska Board of Fisheries to: (1) designate Anchor River Chinook salmon as a stock of management concern, (2) impose more conservative restrictions on the sport fishery, and (3) recommend the Alaska Department of Fish and Game, Division of Sport Fish quantify stock status. High discharge caused by snowmelt run-off and turbid water conditions prevents use of conventional weir technology to assess escapement during the Chinook salmon return during May and early June. Consequently, a Dual Frequency Identification Sonar (DIDSON) was deployed in 2003 to estimate escapement. Escapement was estimated at 9,238 Chinook salmon, compared to an aerial count of 647 Chinook salmon. In 2004, the project expanded to include coho salmon escapement monitoring. To meet this new objective, the DIDSON system was used during the high discharge period in conjunction with a full-weir during the lower stream discharge period. The Chinook salmon escapement estimate for 2004 was 12,016 (SE = 283), while the aerial index was 834, and the coho salmon O. kisutch count was 5,728. Because this more accurate assessment of stock status indicated that escapements are greater and exploitation lower than previously thought, the Board of Fisheries repealed the management concern designation, eliminated the SEG, and liberalized the fishery in November 2004. In the future, relationship between aerial indices and escapement estimates will be evaluated. |
| Keywords: | Anchor River, Chinook salmon, Oncorhynchus tshawytscha, coho salmon, Oncorhynchus kisutch, run timing, stock status, weir, sonar, DIDSON. |