Stock assessment of the chinook salmon return to the Naknek River, Alaska, during 1992
By: by Lewis G. Coggins, Jr. and Allen E. Bingham.
Contributors: Bingham, Allen E.; Alaska. Division of Sport Fish.
Series: Fishery data series -- no. 93-26.
Publisher: Alaska Dept. of Fish and Game, Division of Sport Fish
Published: 1993
Place of publication: Anchorage, Alaska
Language: eng
Number of pages: 78
Subjects: Chinook salmon -- Alaska -- Naknek River.; Salmon fisheries -- Alaska -- Naknek River.
Description: Drift gill nets were used to capture 1,068 adult chinook salmon Oncorhynchus tshawytscha in the lower Naknek River for marking as part of a mark-recapture experiment. Marked fish were recaptured during a creel survey of the sport fishery and during escapement surveys of the spawning grounds. Based on recovery data from the escapement surveys, an estimated 51,344 chinook salmon  635 millimeters entered the lower Naknek River from 5 June until 14 August. During the escapement recovery event in which 681 chinook salmon, 635 millimeters or greater in length, were examined, only 13 had been marked in the marking event. Due to this extremely low recapture rate, and a similarly low recapture rate during the sport fishery recovery event, a host of assumptions required for unbiased estimates of inriver abundance were not tested. Because these assumptions were not addressed and because the estimated inriver abundance minus the estimated sport harvest is nearly nine times as large as the total average historical escapement index, this estimate is believed to be biased high by an unknown amount. An estimated 28,428 hours of effort were expended by recreational anglers fishing the lower Naknek River from 8 June through 31 July 1992. This estimate is 40% below the recent 4-year average (1988-1991) of 47,654 hours. Anglers caught (landed) and harvested (kept) an estimated 3,362 and 2,949 (88% harvested) chinook salmon, 156 and 156 (100% harvested) coho salmon Oncorhynchus kisutch, 456 and 413 (91% harvested) chum salmon Oncorhynchus keta, and 1,760 and 25 (1% harvested) rainbow trout Oncorhynchus mykiss. Age-1.4 (47%) and -1.3 (24%) chinook salmon dominated the harvest. An emergency order which prohibited fishing for chinook salmon in King Salmon Creek and Paul's Creek, as well as the waters surrounding their confluences with the Naknek River, took effect 1 June. These closures were enacted in an attempt to provide adequate chinook salmon escapement into these streams as well as to provide protection to a major milling area located at the confluence of King Salmon Creek and the Naknek River. The emergency order was only partially effective as both Paul's Creek and King Salmon Creek received below average escapements. The spawning escapement index of chinook salmon, as determined by aerial survey counts of live fish in the four major spawning areas, was 2,621 fish which was well below the 1970-1991 average of 5,524 fish.
Notes: "August 1993."

"Partially financed by the Federal Aid in Sport Fish Restoration Act ... under project F-10-8, job no. S-2-1.

Includes bibliographical references (p. 44-48).

Also issued online.