Spawner Recruit Analysis And Escapement Goal Recommendation For Kenai River Late Run Sockeye Salmon

Author : Beverly A. Cross
Publisher :
ISBN 13 :
Total Pages : 96 pages
Book Rating : 4.:/5 (13 download)

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Download or read book Report to the Alaska Board of Fisheries on Spawning Escapement Goal Evaluations for Bristol Bay Salmon written by Beverly A. Cross and published by . This book was released on 1997 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: A workshop was held on September 16-18, 1997 in Anchorage by the Alaska Department of Fish and Game to review Pacific salmon Oncorhynchus escapement goals for major rivers in Bristol Bay. Spawner-return data were analyzed for Kvichak, Naknek, Egegik, Ugashik, Wood, Igushik, Nushagak, and Togiak Rivers sockeye salmon 0. nerka. Sockeye smolt information was reviewed for Kvichak, Egegk, and Ugashik Rivers. Available limnological and juvenile information were analyzed fiom Lake Iliarnna. In addition, spawner-return data for Nushagak River chinook salmon O. tshawytscha were also reviewed. With a few exceptions available data supported current escapement goals in Bristol Bay. Based on this most recent escapement goal evaluation, workshop participants recommended the following changes. They recommended restructuring the escapement goal policy for Kvichak River sockeye salmon to a more robust variable escapement goal. Analyses of available data were inconclusive as to whether the underlying cause of cycles in Kvichak River sockeye production were due to inherent depensatory factors or lack of spawners. The recommended policy included an off-cycle escapement range of 2-10 million sockeye salmon with a minimum goal of 2 million and an exploitation rate of 50% on runs of 4 - 20 million. The point goal for a given off-cycle year would be 50% of the inshore Kvichak run but never less than 2 million or greater than 10 million. A 6 -10 million escapement range was proposed for pre-peak and peak cycle years with a minimum of 6 million and an exploitation rate of 50% on runs of 12 - 20 million. The point goal for a given prepeak or peak cycle year would be 50% of the inshore Kvichak run but never less than 6 million or greater than 10 million. Workshop participants also recommended managing for escapements within the middle of the current escapement goal ranges for Naknek, Egegik, and Ugashik Rivers. The current management objectives or point goals for those rivers are artifacts of past Ricker stock-recruitment models and are no longer supported by the data. Therefore, it was recommended that the management objectives be changed to 1.1 million sockeye salmon for Naknek River, 1.1 million sockeye salmon for Egegik River, and 0.85 million sockeye salmon for Ugashik River. The final recommendation coming out of the workshop was that the sockeye escapement goal range for Togiak River be changed to 100 - 200 thousand sockeye salmon. Available data supported the current management objective of 150 thousand sockeye salmon for Togiak River, but indicated an escapement range of 100 - 200 thousand would on average produce higher yields.