Age-structured state-space spawner-recruit models were fit to 1986-2015 data on abundance, harvest, and age composition for early and late runs of Kenai River Chinook salmon (Oncorhynchus tshawytscha), 75 cm mid eye to tail fork (METF) and longer. Historical annual run abundance, stock recruitment parameters, and fishery management reference points were estimated from these models. Sustainable Escapement Goals of 2,800-5,600 (early run) and 13,500-27,000 (late run) Chinook salmon 75 cm METF and longer are recommended, and their attributes and limitations discussed. Fish 75 cm METF (approximately 33.3 in total length) and longer can be assessed directly by imaging sonar in the Kenai River at river mile 13.7.

The current sustainable escapement goal (700,000–1,200,000) for Kenai River late-run sockeye salmon was established in 2011. For this escapement goal review, the escapement time series and production data were updated through 2018. The fit of 6 spawner–recruit models to data from brood years 1968–2012 and brood years 1979–2012 was examined. Although the classic Ricker model was determined the most appropriate to use given the data, all brood years were estimated to have replaced themselves, which compromised obtaining accurate and precise estimates of most model parameter estimates and biological reference points, including a scientifically defensible estimate of maximum sustained yield. Markov-type yield tables were constructed to evaluate yields at different levels of escapement. We recommend the sustainable escapement goal for Kenai River late-run sockeye salmon be revised to 750,000–1,300,000 fish because the analyses indicated escapements in this range will likely provide better yields.

The objectives of this report are to: 1) describe the productivity and capacity of the Kuskokwim River Chinook salmon stock, as quantified from stock-recruit analyses, 2) recommend a drainage-wide escapement goal based on this information, and 3) revise escapement goals for selected tributaries.

An age-structured state-space spawner–recruit model was fit to estimates of relative and absolute abundance, harvest, and age composition for Copper River Chinook salmon (Oncorhynchus tshawytscha) from 1980 to 2016. Bayesian statistical methods were employed to assess uncertainty in the presence of measurement error, serial correlation, and missing data. Ricker stock-recruit parameters and management reference points were estimated, including the escapement that provides for maximum sustained yield (SMSY). It is recommended that a sustainable escapement goal range of 18,500 to 33,000 fish be adopted for Copper River Chinook salmon. Escapement is evaluated by subtracting estimates of inriver harvest from estimates of inriver abundance. Escapements within this range have a high probability of producing sustainable yields.

The Susitna River drains approximately 52,000 square kilometers of the southern slopes of the Alaska Range and the Talkeetna mountains. This watershed supports wild populations of all 5 species of Pacific salmon and vibrant sport fisheries when production allows. Chinook salmon spawning escapements have been monitored since the late 1970s by aerial survey and a weir has been used to count returning adults on the Deshka River (a tributary) since 1995. The Deshka River is currently managed by an escapement goal based on weir passage whereas several other spawning populations are managed using escapement goals based only on once-per-year aerial surveys. Other fishery data, such as inriver and marine harvest estimates, age estimates, recent mark–recapture abundance estimates, and spawner distribution data are also available. We present a state-space model that incorporates all available datasets to generate annual inriver and spawning escapement abundance estimates of 4 stocks of Susitna River Chinook salmon. These stocks were created by dividing the drainage into geographical units similar to existing management units used in Alaska Department of Fish and Game sport fishing regulations: Deshka River, Eastside Susitna, Talkeetna River, and Yentna River. The state-space model estimates a spawner-recruitment (S-R) relationship for each stock that is used in developing escapement goal recommendations based on the number of spawners that provide maximum sustained yield (SMSY). SMSY was estimated for each stock: 12,564 for Deshka River; 12,971 for Eastside Susitna; 10,570 for Talkeetna River; and 13,614 for Yentna River. We used a decision matrix to choose escapement goals based on the probability of achieving maximum sustained yield for the 4 stocks. We recommend discontinuing escapement goals for individual spawning populations within these stocks and replacing them with stock-based escapement goals of 9,000–18,000 for Deshka River, 13,000–25,000 for Eastside Susitna, 9,000–17,500 for Talkeetna River, and 13,000–22,000 for Yentna River stocks.