Marking, enumeration, and size estimation for coho and chinook salmon smolt releases into upper Cook Inlet, Alaska in 1994

Description

Southcentral Alaska contains the majority of the state's human population and receives the vast majority of the state's fishing pressure, both of which are increasing (Mills 1993). To meet the growing demand on the sport fishery resource, hatchery-reared chinook salmon Oncorhynchus tshawytscha and coho salmon Oncorhynchus kisutch smolt have been stocked in numerous locations throughout Southcentral Alaska to improve or create terminal sport fisheries. Marking and collection of release data at the Crooked Creek, Elmendorf, and Fort Richardson hatcheries were standardized for each of the stocking projects in 1994. This report presents the results of the 1994 marking program. In addition, three different smolt enumeration techniques are discussed, and the size composition of each release group is also presented and discussed. Over 560,000 coho and chinook salmon smolt released at 11 locations in Cook Inlet were marked with an adipose finclip and a coded wire tag. Long-term (>30 d) tag retention ranged from 94.8% to 99.2%. Comparison of the three smolt enumeration techniques revealed interesting trends. First, in most instances the mark-recapture estimate was the lowest of the three techniques and the hatchery inventory estimate was the highest. Second, the difference between the mark-recapture and the water volume estimates was not consistent for all groups. Third, the discrepancy pattern between the mark-recapture estimate and the hatchery inventory estimate was consistent for most groups at each hatchery.

Subjects

Genres

• Statistics

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