Sockeye salmon were sampled for genetic tissue in the lower Kenai River at river mile (RM) 8.6 during the 2018–2020 early runs (prior to 1 July) for genetic mixed stock analysis (MSA) of stock composition for 3 reporting groups (Russian River Early, Russian River Late, and Kenai River Other) and 5 temporal strata (16 May–3 June, 4–10 June, 11–16 June, 17–23 June, and 24–30 June) each year. The MSAs represent the first stock composition estimates for sockeye salmon entering the Kenai River during the early run. Stock compositions were dominated by Russian River Early fish each year, especially for strata occurring prior to 24 June. Daily Kenai River RM 13.7 sonar passage estimates of fish between 40 cm and 75 cm (small fish) were used with stock composition estimates by stratum and summed to estimate Russian River Early sockeye salmon passage prior to 1 July each year. Russian River Early fish represented an estimated 0.91 (2018), 0.92 (2019), and 0.75 (2020) of the estimated small fish passage at RM 13.7 each year and averaged 0.86 for all 3 years (2018–2020). Estimated passage of Russian River Early fish was highest for the 4–10 June stratum (35% of each year’s early run, on average) and the 11–16 June stratum (28% of each year’s early run, on average), with those 2 strata accounting for 62% of estimated Russian River Early fish passage on average at RM 13.7. The last stratum (24–30 June) had the lowest estimated passage of Russian River Early fish, accounting for 7% of each year’s early run, on average. These results will be used to better predict inseason run strengths of Russian River early-run sockeye salmon, thereby increasing management precision to meet the escapement goal.

Chinook salmon were sampled for genetic tissue and age, sex, and length from the Upper Cook Inlet Eastside set gillnet (ESSN) commercial fishery in 2022. Mixed-stock analysis (MSA) was conducted on tissue samples collected to represent harvest by reporting group and size. Reported harvest in the ESSN fishery was 341 Chinook salmon of all sizes (all-fish harvest), with an estimated composition of 219 (64%) Kenai River mainstem, 67 (20%) Kasilof River mainstem, 53 (15%) Cook Inlet other, and 2 (1%) Kenai River tributaries fish. Kenai River mainstem fish have composed on average 70% of the all-fish harvest since 2010, ranging from 61% (2014) to 79% (2017). Estimated harvest of large (75 cm mid eye to tail fork [METF] and longer) Kenai River mainstem Chinook salmon in 2022 was 41 fish (12% of the all-fish harvest and 66% of the large-fish harvest). Large Kenai River mainstem fish have composed on average 30% of the all-fish harvests since 2010 ranging from 12% (2022) to 63% (2017). Large Kenai River mainstem fish have composed on average 68% of the large-fish harvest ranging from 60% (2010 and 2019) to 79% (2017). Age composition of the all-fish harvest in 2022 was 24% age-1.1 (jacks), 53% age-1.2, 16% age-1.3, and 7% age-1.4 fish. Sex composition of the all-fish harvest was 79% males and 21% females. The average METF length of sampled Chinook salmon was 609 mm in 2022, the lowest ever observed.

Results of a creel survey conducted to estimate angler effort, catch and harvest of Chinook salmon, Oncorhynchus tshawytscha, on the Kenai River between the Soldotna Bridge and the Warren Ames Bridge from May 16 to July 31, 2006.

Age, sex, and length composition information will be collected from harvested Chinook salmon in the Upper Cook Inlet Eastside set gillnet (ESSN) commercial fishery in 2021–2023. Genetic tissues from the harvest will also be collected and archived for potential future mixed stock analysis. The primary goal of the study is to estimate the age, sex, and length composition of the Chinook salmon harvest and to estimate the harvest of large (>75 cm METF) Kenai River Chinook salmon in the ESSN fishery for each season (2021–2023). Age, sex, and length composition will be estimated for each temporal and geographic stratum and for each season. The harvest of large Kenai River Chinook salmon will be estimated using historical (2010–2020) large fish stock compositions relative to the total large fish harvest for each temporal and geographic stratum and summed to the total for each season.

"Smolt abundance is commonly estimated using trap efficiency-based methods; however, few studies have investigated the accuracy of trap efficiency estimates. The objectives of this study were to: (1) test the hypotheses that (i) trap efficiency is not affected by release timing nor release distance, (ii) trap efficiency-based estimates of smolt abundance are concordant with smolt-adult mark-recapture estimates, and (2) evaluate if water level and turbidity influence trap efficiency. In Deep Creek, Alaska, during 2001 and 2002, coho salmon Oncorhynchus kisutch smolt abundance was estimated using trap efficiency-based methods and compared to independent smolt-adult mark-recapture estimates. Marked smolts were released at two times of day (1200 hours and 0000 hours) and two release distances upstream of the trap (400 m and 1500 m) every 2 to 4 d throughout each year. Trap efficiency estimates were highly variable (range 0%-55%) and trap efficiency-based estimates of abundance were not concordant with smolt-adult mark-recapture estimates. Release timing and turbidity significantly influenced trap efficiency, whereas release distance did not. Several assumptions of the trap efficiency approach were not met, which produced biased estimates and conflicting results among years when comparing estimation techniques. These results suggest that assumptions of the trap efficiency-based methods be fully assessed to accurately estimate smolt abundance"--Leaf iii.

Chinook salmon were sampled for genetic tissue and age, sex, and length from the Upper Cook Inlet Eastside set gillnet commercial fishery in 2018. Mixed-stock analysis (MSA) was conducted on tissue samples collected to represent harvest by date and area. Reported harvest was 2,312 Chinook salmon, with an estimated composition of 1,710 (75%) Kenai River mainstem, 428 (19%) Kasilof River mainstem, 77 (3%) Kenai River tributaries, and 69 (3%) Cook Inlet Other fish, and 28 fish not represented in the MSA. Kenai River mainstem fish have composed on average 72% of the harvest since 2010, ranging from 61% in 2014 to 79% in 2017. Estimated harvest of large (75 cm mid eye to tail fork and longer) Kenai River mainstem Chinook salmon in 2018 was 555 fish (24% of total harvest and 77% of total large fish harvest). A retrospective MSA by size, time, and area was conducted on tissue samples collected in 2010, 2011, 2013, and 2014. Including these results and those from 2015 to 2018, large Kenai River mainstem fish have composed on average 36% of the total harvest since 2010 ranging from 23% in 2013 to 63% in 2017. Large Kenai River mainstem fish have composed on average 70% of the total large fish harvest ranging from 60% in 2010 to 79% in 2017. Age composition of all fish in 2018 was 13% age-1.1 (jacks), 54% age-1.2, 12% age-1.3, 21% age-1.4, and less than 1% age-1.5 fish. The combined percentage of jacks and age-1.2 fish (67% in total) was the highest observed and the percentage of age-1.3 fish (12%) was the lowest observed since sampling began in 1987. Sex composition of the Chinook salmon harvest was 82% males and 18% females. Average mid eye to tail fork length was 685 mm, the 2nd lowest ever observed and lowest since 2013.

In August 2021, we investigated the feasibility of using drift gillnets at river mile (RM) 19 to examine the species composition and spatial distribution of salmon migrating past the Division of Commercial Fisheries sonar site. Currently, the site uses dual-frequency identification sonar (DIDSON) to estimate sockeye salmon (Oncorhynchus nerka) passage, and fish wheels are used to sample salmon for species composition and biological characteristics. Drift gillnetting was conducted for 6 days during August 5–24, 2021 using 9.1 m length gillnets consisting of 1 of 3 mesh sizes: 4 in, 4.75in, or 5 in (10.2, 12.1, and 12.7 cm, respectively). Gillnetting occurred in 6 areas (0–10 m, 10–20 m, and 20–30 m) off each river bank, representing the area of the river where sonar data are collected to estimate passage of migrating sockeye salmon (sonar zones) and in 2 areas 0–10 m downstream of the fish wheel located on each river bank (fish wheel zones). Sockeye salmon composed the majority of the catch in both fish wheel and nearshore sonar zones. Sockeye salmon proportions declined offshore (>10 m) and during later sampling dates. Our results show that drift gillnets of various mesh sizes can be employed to capture migrating salmon at the Kenai River RM 19 sonar site. We present recommendations for future study designs.

A multiple-event mark–recapture study was conducted on rainbow trout (Oncorhynchus mykiss) in the upper Kenai River in 2018. The objectives of this study were to estimate the abundance and fork length (FL) composition of rainbow trout in the most heavily fished section of the upper Kenai River (river miles 69.6–73.2) and to compare these estimates to those from previous surveys conducted in 1986, 1987, 1995, 2001, and 2009 on the same stretch of river. There were an estimated 10,568 (SE 608) rainbow trout at least 200 mm FL and 8,482 (SE 495) rainbow trout at least 300 mm FL in the study area. Abundance of fish at least 200 mm FL was 79% higher than in 2009 and 24% higher than in 2001. Abundance of fish at least 300 mm FL was 66% higher than in 2009, 33% higher than in 2001, and 52% higher than in 1995. Most of the rainbow trout were between 250 mm and 449 mm FL, accounting for 88% of the population. Approximately 75% of the population was less than 400 mm FL, which is the approximate upper length (16 inches total length) of fish allowed to be harvested by regulation. Overall, rainbow trout abundance in 2018 was considerably higher than in any other study year, but the number of fish more than 450 mm FL was only 743 (SE 71), which was less than half of what was observed in 1995, 2001, and 2009.

This study will describe the geographic spawning distribution of radiotagged coho salmon in the Kenai River drainage for 2 years (2023 and 2024). Drift gillnets will be employed in the Kenai River to capture and tag adult coho salmon with radio transmitters. Radiotelemetry will be used to uniquely identify and track tagged coho salmon to spawning destinations. Up to 490 radio transmitters will be deployed annually between August 1 and October 31 each year. Movements of radiotagged coho salmon will be documented using a combination of fixed data-logging receiver stations and mobile tracking using boats and fixed-wing aircraft. This project will be the 2nd and 3rd year of a 3-year collaboration between the Alaska Department of Fish and Game (ADF&G) and the U.S. Fish and Wildlife Service (USFWS). The USFWS conducted the first year of the project in 2022, and ADF&G and USFWS will be collaborating on the radiotelemetry project in 2023 and 2024.