Estimation of the abundance of late-run chinook salmon in the Kenai River based on exploitation rate and harvest, 1997

Description

The inriver return of the late run of chinook salmon to the Kenai River was estimated to assess the accuracy of the inriver return estimate obtained with split-beam hydroacoustic (sonar) gear. In this study inriver return was estimated as a function of harvest and exploitation rate by the sport fishery between the chinook salmon sonar site and the Soldotna Bridge from 1-31 July 1997. Harvest estimated by an onsite creel survey was 9,809 (SE = 704) fish. Exploitation rate was estimated by monitoring and determining fate of chinook salmon fitted with a radio transmitter. Marked chinook salmon were combined into five groups based on time of entry into the river. Exploitation rate did not differ (P > 0.05) by gender, size, or time-of-entry group. A total of 53 marked chinook salmon were harvested by the sport fishery. The estimated exploitation rate was 0.251 (SE = 0.020). The inriver return of 39,080 (SE = 4,207) fish estimated by this study was significantly (P = 0.01) less than that obtained by sonar (49,933 fish; SE = 876). These same results were observed in 1996 and indicate the sonar gear may be classifying some targets as chinook salmon that are actually sockeye salmon. Sonar data other than that currently used to classify targets as chinook salmon should be examined to better discriminate and more accurately determine targets that are chinook salmon.

Subjects

Series Statement

• Fishery data series -- no. 99-8.

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