Historical Estimates of Run and Escapement for Chinook Salmon Returning to the Nushagak River, 1968–2020 PDF Download
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Author: Jordan Head Publisher: ISBN: Category : Chinook salmon fisheries Languages : en Pages : 0
Book Description
A maximum likelihood model was developed to estimate the 1968–2020 drainagewide run size and escapement of Nushagak River Chinook salmon (Oncorhynchus tshawytscha). The model simultaneously combined information by direct observations of escapement at 8 locations (1 tower and 7 aerial surveys); harvest of fish from commercial, subsistence, and sport fisheries; inriver abundance indices from the Nushagak River sonar project; and inriver abundance estimates from acoustic tag and mark–recapture studies. Results showed that reconstructed total run size ranged from 74,000 to 629,000 Chinook salmon with an average run size of 282,000 fish, and escapement ranged from 49,000 to 476,000 fish with an average of 210,000 fish. The model estimated total run and escapement appeared to be reasonable and tracked well with previous estimates. The major deficiency of this model is the absence of overlapping, long-term escapement and run monitoring data.
Author: Jordan Head Publisher: ISBN: Category : Chinook salmon fisheries Languages : en Pages : 0
Book Description
A maximum likelihood model was developed to estimate the 1968–2020 drainagewide run size and escapement of Nushagak River Chinook salmon (Oncorhynchus tshawytscha). The model simultaneously combined information by direct observations of escapement at 8 locations (1 tower and 7 aerial surveys); harvest of fish from commercial, subsistence, and sport fisheries; inriver abundance indices from the Nushagak River sonar project; and inriver abundance estimates from acoustic tag and mark–recapture studies. Results showed that reconstructed total run size ranged from 74,000 to 629,000 Chinook salmon with an average run size of 282,000 fish, and escapement ranged from 49,000 to 476,000 fish with an average of 210,000 fish. The model estimated total run and escapement appeared to be reasonable and tracked well with previous estimates. The major deficiency of this model is the absence of overlapping, long-term escapement and run monitoring data.
Author: Tracy R. Hansen Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 0
Book Description
Counting tower techniques were used to estimate Chinook salmon Oncorhynchus tshawytscha escapement in the Gulkana River during 2019, 2020, and 2021. The counting tower was located on the mainstem Gulkana River about 3.25 river kilometers upstream of the West Fork Gulkana River confluence. The estimated escapement of Chinook salmon was 8,400 (SE = 436; 95% CI = 7,546–9,254) in 2019, 2,504 (SE = 216; 95% CI = 2,080–2,928) in 2020, and 3,402 (SE = 273; 95% CI = 2,867–3,937) in 2021. These numbers do not represent total inriver escapement, just escapement above the counting tower site. The 2019 estimated escapement of Chinook salmon was the highest on record since the inception of the project in 2002, whereas the 2020 and 2021 estimated escapements were below the average for the years 2002–2018. The dates of the 25th, 50th, and 75th percentile of cumulative passage of Chinook salmon past the Gulkana River counting tower have been getting later since the project’s inception in 2002. The estimated escapement of sockeye salmon O. nerka during the counting tower’s operational period was 20,850 (SE = 661; 95% CI = 19,555–22,145) in 2019, 13,500 (SE = 574; 95% CI = 12,375–14,625) in 2020, and 13,924 (SE = 711; 95% CI = 12,531–15,317) in 2021. Counting tower operations were extended during 2019–2021 to enumerate more of the sockeye salmon return.
Author: Sean D. Larson Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 46
Book Description
A maximum likelihood model was used to estimate the 2020 drainagewide run size and escapement of Kuskokwim River Chinook salmon (Oncorhynchus tshawytscha). The total run was estimated to be 124,486 fish (95% CI: 102,661–150,952) and escapement was estimated to be 88,285 fish (95% CI: 66,460–114,751). Model estimates were informed by direct observations of the 2020 escapement at 15 locations (3 weirs and 12 aerial surveys) and harvest, combined with historical observations of escapement (up to 6 weirs and 14 aerial surveys), harvest, test fishery, and mark–recapture data dating back to 1976. Model results are adequate to draw broad conclusions about the 2020 run and escapement. The 2020 total run of Chinook salmon was below the 1976–2019 average of 215,870 fish. The drainagewide sustainable escapement goal of 65,000–120,000 was met in 2020. The 2021 Kuskokwim River Chinook salmon forecast is for a range of 94,000–155,000 fish.
Author: Sean D. Larson Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 46
Book Description
A maximum likelihood model was used to estimate the 2019 drainagewide run size and escapement of Kuskokwim River Chinook salmon (Oncorhynchus tshawytscha). Total run and escapement were estimated to be 226,987 (95% CI: 182,811–281,839) and 188,483 (95% CI: 144,307–243,335) fish, respectively. Model estimates were informed by direct observations of the 2019 escapement at 16 locations (4 weirs and 12 aerial surveys) and harvest, combined with historical observations of escapement (up to 6 weirs and 14 aerial surveys), harvest, test fishery, and mark–recapture data dating back to 1976. Model results are adequate to draw broad conclusions about the 2019 run and escapement. The 2019 total run of Chinook salmon was the largest since 2007 and was probably above the 1976–2018 average of 215,529 fish. The drainagewide sustainable escapement goal of 65,000–120,000 was exceeded in 2019. The 2020 Kuskokwim River Chinook salmon forecast is for a range of 193,000–261,000 fish.
Author: Sean D. Larson Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 46
Book Description
A maximum likelihood model was used to estimate the 2021 drainagewide run size and escapement of Kuskokwim River Chinook salmon (Oncorhynchus tshawytscha). The total run was estimated to be 129,751 (95% CI: 94,489–178,171) fish and escapement was estimated to be 101,000 (95% CI: 65,738–149,420) fish. Model estimates were informed by direct observations of the 2021 escapement at 3 weirs and 2021 harvest, combined with historical observations of escapement (up to 6 weirs and 14 aerial surveys), harvest, test fishery, and mark–recapture data dating back to 1976. Model results are adequate to draw broad conclusions about the 2021 run and escapement. The 2021 total run of Chinook salmon was below the 1976–2020 average of 214,475 fish. The drainagewide sustainable escapement goal of 65,000–120,000 was met in 2021. The 2022 Kuskokwim River Chinook salmon forecast is for a range of 99,000–161,000 fish.
Author: Sean D. Larson Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 0
Book Description
A maximum likelihood model was used to estimate the 2022 drainagewide run size and escapement of Kuskokwim River Chinook salmon (Oncorhynchus tshawytscha). The total run was estimated to be 142,495 (95% CI: 107,579–188,743) fish, and escapement was estimated to be 107,980 (95% CI: 73,064–154,228) fish. Model estimates were informed by direct observations of the 2022 escapement at 3 weirs and 2022 harvest, combined with historical observations of escapement (up to 6 weirs and 14 aerial surveys), harvest, test fishery, and mark–recapture data dating back to 1976. Model results are adequate to draw broad conclusions about the 2022 run and escapement. The 2022 total run of Chinook salmon was below the 1976–2021 average of 211,081 fish. The drainagewide sustainable escapement goal of 65,000–120,000 was met in 2022. The 2022 Kuskokwim River Chinook salmon forecast is for a range of 115,000–170,000 fish.
Author: James William Savereide Publisher: ISBN: Category : Chinook salmon fisheries Languages : en Pages : 46
Book Description
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.
Author: Roderick L. Haig-Brown Publisher: Lyons Press ISBN: 9781558215818 Category : Chinook salmon Languages : en Pages : 0
Book Description
Haig-Brown captures the full sweep of the Chinook migration in this dramatic life history of one salmon from her hatching through her mating
Author: Nathan Frost Publisher: ISBN: Category : Chinook salmon Languages : en Pages : 0
Book Description
This plan describes the coded-wire tagging of juvenile Chinook salmon Oncorhynchus tshawytscha on the Unuk River for the 2019 and 2020 brood years, which covers the coded-wire tagging of parr in fall of 2020 and 2021 and smolt in spring of 2021 and 2022, and sampling returning adults for age, sex, length, and coded-wire tags in escapement from the 2022 through 2027 return years. This study provides estimates of smolt and parr abundance, overwinter (freshwater) survival, mean lengths of juveniles, and harvest information of Chinook salmon originating from the Unuk River in Southeast Alaska. A separate project will be conducted on the Unuk River that employs aerial and foot survey peak counts to estimate large (≥660 mm mid eye to fork of tail length) adult Chinook salmon returning to the river in 2020 and 2021. The primary goals of this and the companion study are to estimate inriver run size, total run size, marine harvest-exploitation rate and harvest distribution, smolt and parr abundance, marine survival (smolt to adult) and overwinter survival (parr to smolt). The Alaska Department of Fish and Game uses this information to make local and regional management decisions, and the Pacific Salmon Commission uses the data for coastwide management and stock assessment through the Chinook Technical Committee.
Author: Jordan Head
Author: Jordan Head
Author: Tracy R. Hansen
Author: Sean D. Larson
Author: Sean D. Larson
Author: Sean D. Larson
Author: Sean D. Larson
Author: Ronald H. Williams
Author: James William Savereide
Author: Roderick L. Haig-Brown
Author: Nathan Frost