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Division: Sport Fish
Title: Marking, enumeration, and size estimation for coho and chinook salmon smolt releases into upper Cook Inlet, Alaska in 1996.
Author: Starkey, D., C. Olito and P. Hansen
Year: 1997
Report ID: Alaska Department of Fish and Game, Fishery Data Series No. 97-13, Anchorage.
Abstract: Over half of Alaskans live in Southcentral Alaska, which receives the vast majority of the state's sport fishing effort. The population of Southcentral and sport fishing effort are increasing. To meet the growing demand on the sport fishery resource, hatchery-reared chinook salmon Oncorhynchus tshawytscha and coho salmon O. kisutch smolt have been stocked in numerous locations throughout Southcentral Alaska to improve or create terminal sport fisheries. 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 in 1996. Tag retention for individual raceways ranged from 93.8% to 99.7%. Our production goal was to make 80% of the coho salmon smolt within the size range of 15.1 g to 25.0 g. Coho salmon produced at Ft. Richardson Hatchery and released into Bird Creek, Wasilla Creek, and Campbell and Ship creeks (both Anchorage urban streams) met the goal. Our production goal for chinook salmon smolt was to make 80% of the smolt within the range of 5.1 g to 15.0 g. Ninilchik River chinook salmon smolt produced at Ft. Richardson Hatchery were close to achieving the production goal with 79.1% of the smolt within the desired range. None of the remaining chinook salmon release groups at Ft. Richardson Hatchery, nor the chinook salmon release groups at Elmendorf Hatchery, achieved the production goal. Three smolt enumeration techniques were compared. In most instances the mark-recapture estimate was the lowest of the three techniques at both hatcheries. While no trend was evident when comparing the hatchery inventory estimates with the water volume estimates at Fort Richardson Hatchery, the water volume estimate was higher than the hatchery inventory estimate in most instances at Elmendorf Hatchery. In most instances, the differences between hatchery inventory estimates and mark-recapture estimates at Elmendorf Hatchery depended upon the method used to obtain the hatchery inventory estimate. Therefore, we used the mark-recapture method for estimating numbers of smolt released.
Keywords: Hatchery, marking, coded wire tags, chinook salmon, Oncorhynchus tshawytscha, coho salmon, Oncorhynchus kisutch, mark-recapture, hatchery inventory, water volume, tag retention, size composition. McPherson, S. A., D. R. Bernard, M. S. Kelley, P. A. Milligan, and P. Timpany.