Evidence that fisheries management in support of trophy fishing for Kenai River Chinook likely is a contributing factor to the decline of the Kenai River's Chinook populations. See the following note.
The evidence of trophy fishing contributing to genetic selection is particularly clear -- and important -- with regard to Kenai's small population early-run Chinook, which is on the verge of threatened status.
Still, sorting out the influence of genetic selection from other contributing factors should not be over-simplified. There are serious issues with Fish and Game's data. Their baseline data has large discrepancies between sonar and weir counts, and other discrepancies between the old sonar data and the new, and issues with regard to calibrating sonar counts with in-river test net catches. Fish and Game publishes data in terms of annual percentages, but seems to significantly ignore brood year data, which distinguishes contributions to returns by brood year, which is important.
Seeing disproportionate number of jacks should not invite the conclusion that management should declare an open season on jacks for the in-river fishery.
At this point, I believe Fish and Game needs help, and I hope they could get support for an independent review of the Kenai River Fisheries management by a Chinook Salmon Expert Panel composed of people of expertise of the caliber we recently have seen in the Arctic-Yukon-Kuskokwim Chinook Salmon Research Action Plan, which I have included in the google drive directory below.
Copies of the papers are stored in google drive here:
Forschungsverbund Berlin e.V. (FVB). "Fishing; More protection for big ones." ScienceDaily. ScienceDaily, 2 January 2014. http://www.sciencedaily.com//releases....
Hard, Jeffrey J., Wertheimer, Alex C., Heard, William R, Martin, Roy M. Early Male Maturity in Two Stocks of Chinook Salmon (Oncorhynchus Tshawytscha) Transplanted To An Experimental Hatchery in Southeastern Alaska, Aquaculture, 48 (1985) 351-359
Hankin, David G., Nicholas, Jay W., Downey, Timothy W. Evidence for Inheritance of Age of Maturity in Chinook Salmon (Oncorhynchus tshawytscha), Can. J. Fish. Aquat. Sci. (1985) 50: 347-358
Heath, Daniel D., Devlin, Robert H., Heath, John W., Iwama, George K. Genetic, environmental and interaction effects on the incidence of jacking in Oncorhynchus tshawytscha (chinook salmon), Heredity 72 (1994) 146-154
Roni, Philip, Quinn, Thomas P. Geograpc Variation in Size and Age of North American Chinook Salmon, North American Journal of Fisheries Management (1995) 15:325-345
McKinley, Timothy R., King, Bruce E., Hasbrouck, James J., Clark, Robert A. Biological Issues of the Kenai River and Kasilof River Early-run King Salmon Fisheries, Alaska Department of Fish and Game (2002) Special Publication No. 02-02
Olsen, Esben M., Heino, Miko, Lily George R., Morgan, M. Joana, Brattey, john, Ernande, Bruno, Dieckmann, Ulf. Maturation trends indicative of rapid evolution preceded the collapse of northern cod, Nature Publishing Group (2004) Vol 428
Birkeland, Charles, Dayton, Paul K. The importance in fishery management of leaving the big ones, Trends in Ecology and Evolution (2005) Vol. 20 No. 7
Jorgensen, Christian, Enberg, Katja, Dunlop, Erin S., Arlinghaus, Robert, Boukal, David S., Brander, Keith, Ernande, Bruno, Goerdmark, Anna, Johnston, Fiona, Matsumura, Suichi, Pardoe, Heidi, Raab, Kristina, Silva, Alexandra, Vainika, Anssi, Dieckmann, Ulf, Heino, Miko, Rijnsdorp, Adriaan D. Managing Evolving Fish Stocks, Science (2007) Vol 318. no. 5854, pp. 1247 - 1248
Kuparinen, Anna, Merila, Juha. Detecting and managing fisheries-induced evolution, Trends in Ecology and Evolution (2007) Vol. 22 No. 22
Johnson, Marc A, Friesen, Thomas A. Age at Maturity, Fork Length, and Sex Ratio of Upper Willamete River Hatchery Spring Chinook Salmon, North American Journal of Fisheries Management (2013) 33:318-328
Shields, Pat, Dupuis, Aaron, Upper Cook Inlet Commercial Fisheries Annual Management Report, Alaska Department of Fish and Game (2013) Fishery Management Report No. 13-49
McKinley, Timothy R., Fleischman, Steven J. Run Reconstruction, Spawner-recruit Analysis, And Escapement Goal Recomendation for Early-Run Chinook Salmon in the Kenai River, Alaska Department of Fish and Game (2013) Fisheries Manuscript Series No. 13-03
Eskelin, Tony, Barclay, Andrew W., Antonovich, Anton. Mixed Stock Analysis and Age, Sex, and Length Composition of Chinook Salmon in the Eastside Set Gillnet Fishery in Upper Cook Inlet, Alaska, 2010-2013, Alaska Department of Fish and Game (2013)
Alaska Department of Fish and Game website: