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Author: Shane R. Ransbury
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 0
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Book Description
From 2017 to 2020, the Alaska Department of Fish and Game, Division of Commercial Fisheries, conducted stock assessment programs to estimate the escapement and harvest of Chilkat Lake sockeye salmon (Oncorhynchus nerka). Escapement was estimated with a Dual-frequency Identification Sonar (DIDSON) and weir near the outlet of Chilkat Lake, and age, length, and sex data were collected and analyzed each year. Sockeye salmon escapements, based on expanded DIDSON counts, were 88,197 fish in 2017, 108,047 fish in 2018, 136,091 fish in 2019, and 50,746 fish in 2020. Estimated escapements fell within the biological escapement goal range of 70,000–150,000 sockeye salmon in all but one year (2020). A pair of fish wheels were operated on the Chilkat River to provide inseason information on Chilkat sockeye salmon run strength to assist in management of the District 15 commercial drift gillnet fishery. Genetic stock identification was conducted to determine the stock composition of sockeye salmon harvested annually in the District 15 commercial drift gillnet fishery. Estimated commercial harvests of Chilkat Lake sockeye salmon were 5,698 fish in 2017, 19,235 fish in 2018, 40,935 fish in 2019, and 8,776 fish in 2020. Estimated annual harvest rates (not including subsistence or sport harvests) ranged from 6.1% (2017) to 23.1% (2019), and Chilkat Lake sockeye salmon accounted for an estimated 14.3% (2017) to 23.5% (2018) of the annual commercial sockeye salmon harvest in District 15. Zooplankton populations at Chilkat Lake have improved steadily since the late 2000s; historical peaks in the abundance of copepods and cladocerans (particularly Daphnia), the preferred prey of juvenile sockeye salmon, were observed in 2020 and 2019, respectively.
Author: Shane R. Ransbury
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 0
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Book Description
From 2017 to 2020, the Alaska Department of Fish and Game, Division of Commercial Fisheries, conducted stock assessment programs to estimate the escapement and harvest of Chilkat Lake sockeye salmon (Oncorhynchus nerka). Escapement was estimated with a Dual-frequency Identification Sonar (DIDSON) and weir near the outlet of Chilkat Lake, and age, length, and sex data were collected and analyzed each year. Sockeye salmon escapements, based on expanded DIDSON counts, were 88,197 fish in 2017, 108,047 fish in 2018, 136,091 fish in 2019, and 50,746 fish in 2020. Estimated escapements fell within the biological escapement goal range of 70,000–150,000 sockeye salmon in all but one year (2020). A pair of fish wheels were operated on the Chilkat River to provide inseason information on Chilkat sockeye salmon run strength to assist in management of the District 15 commercial drift gillnet fishery. Genetic stock identification was conducted to determine the stock composition of sockeye salmon harvested annually in the District 15 commercial drift gillnet fishery. Estimated commercial harvests of Chilkat Lake sockeye salmon were 5,698 fish in 2017, 19,235 fish in 2018, 40,935 fish in 2019, and 8,776 fish in 2020. Estimated annual harvest rates (not including subsistence or sport harvests) ranged from 6.1% (2017) to 23.1% (2019), and Chilkat Lake sockeye salmon accounted for an estimated 14.3% (2017) to 23.5% (2018) of the annual commercial sockeye salmon harvest in District 15. Zooplankton populations at Chilkat Lake have improved steadily since the late 2000s; historical peaks in the abundance of copepods and cladocerans (particularly Daphnia), the preferred prey of juvenile sockeye salmon, were observed in 2020 and 2019, respectively.
Author: Julie Bednarski
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 64
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Book Description
Since 1967 the Alaska Department of Fish and Game, Division of Commercial Fisheries, has operated a stock assessment program to estimate escapements and harvests of Chilkat sockeye salmon (Oncorhynchus nerka). Sockeye salmon were counted through a weir near the outlet of Chilkat Lake, and age, length, and sex data were collected and analyzed each year. Since 1994, mark-recapture studies were conducted to estimate Chilkat sockeye salmon escapements. Since the start of the 2008 season, DIDSON sonar has been used at the weir site to directly enumerate adult sockeye salmon escapement into Chilkat Lake. Visual scale pattern analysis was conducted to determine the proportion of Chilkat sockeye salmon harvested annually in the District 15 commercial drift gillnet fishery. In addition, limnological sampling was conducted in Chilkat Lake and analyzed each year. The intent of this report was to review Chilkat sockeye salmon stock assessment data from 1971 to 2016. The visual and DIDSON weir counts provide an index of escapement; however concerns regarding mark-recapture as a reliable index of abundance lead us to recommend eliminating mark-recapture studies in 2017 and, instead, maintain the DIDSON to estimate escapement into Chilkat Lake. We also recommend reviewing the current Chilkat Lake biological escapement goal to ensure that the goal and escapement estimates are in the same units, which is currently based on mark-recapture units. An average of 77,800 Chilkat Lake sockeye salmon were harvested annually in the District 15 commercial drift gillnet fishery (1976-2016). A comparison of historical fish wheel counts to Chilkat Lake escapement estimates demonstrates that the fish wheel project provides a rough indication of Chilkat Lake run strength. Zooplankton samples from Chilkat Lake were composed primarily of one species of copepod (Cyclops columbianus) and three species of cladocerans (Bosmina longerostris, Daphnia longiremus, and Daphnia rosea).
Author: Randall L. Bachman
Publisher:
ISBN:
Category : Chum salmon
Languages : en
Pages : 74
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Book Description
Discusses the mark-recapture studies of adult Chilkat River sockeye (Oncorhynchus nerka) and chum (O. keta) salmon in 2003 and 2004 by the Alaska Department of Fish and Game and the Northern Southeastern Regional Aquaculture Association. These studies were done in order to estimate the escapement of chum and sockeye salmon in the Chilkat River, and sockeye salmon in Chilkat Lake, and to summarize age, sex, and length compositions for these populations.
Author: Randall L. Bachman
Publisher:
ISBN:
Category : Chum salmon
Languages : en
Pages : 49
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Author: Nicole L. Zeiser
Publisher:
ISBN:
Category : Escapement (Fisheries)
Languages : en
Pages : 38
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Book Description
The Chilkat Lake sockeye salmon (Oncorhynchus nerka) run, which spawns near Haines, is one of the largest in Southeast Alaska and contributes substantially to harvests in the District 15 commercial drift gillnet fishery in Lynn Canal. This operational plan outlines objectives, methods, and timelines for conducting sockeye salmon stock assessment designed to (1) estimate annual escapement, (2) provide information for inseason fishery management, and (3) reconstruct runs and assess stock status. The Chilkat Lake sockeye salmon run is managed for a biological escapement goal of 70,000–150,000 fish, which is enumerated with a Dual-Frequency Identification Sonar (DIDSON) system operated in conjunction with a standard picket weir located just downstream of the lake outlet. Genetic mixed stock analysis of weekly sockeye salmon harvests in the District 15 commercial drift gillnet fishery provides stock composition estimates that guide inseason management of the fishery (detailed in a separate Chilkoot Lake sockeye salmon operational plan). Biological sampling, along with escapement enumeration and stock-specific harvest data, allows for total run reconstruction required for escapement goal review. This project also supports the collection of basic limnology information at Chilkat Lake.
Author: Shane R. Ransbury
Publisher:
ISBN:
Category : Escapement (Fisheries)
Languages : en
Pages : 0
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Book Description
From 2016 to 2019, the Alaska Department of Fish and Game, Division of Commercial Fisheries, continued a stock assessment program that began in 1976 to estimate escapements and harvests of Chilkoot Lake sockeye salmon (Oncorhynchus nerka). Sockeye salmon were counted through a weir near the outlet of Chilkoot Lake, and age, length, and sex data were collected and analyzed each year. Sockeye salmon escapements at the weir were 86,721 fish in 2016, 43,098 fish in 2017, 85,463 fish in 2018, and 140,378 fish in 2019, all of which fell within or exceeded the sustainable escapement goal range of 38,000–86,000 fish. Ocean-age-3 sockeye salmon (ages 1.3 and 2.3 combined) of both sexes were the shortest in length since scale sampling began in 1982. The stock compositions of sockeye salmon harvested annually in the District 15 commercial drift gillnet fishery were estimated through scale pattern analysis (2016) and genetic stock identification (2017–2019). Estimated commercial harvests of Chilkoot Lake sockeye salmon were 119,843 fish in 2016, 1,933 fish in 2017, 33,969 fish in 2018, and 149,586 fish in 2019. Estimated harvest rates (including subsistence and sport harvests) were 59% in 2016, 9% in 2017, 31% in 2018, and 52% in 2019. Estimated fall sockeye salmon fry populations at Chilkoot Lake were 42% above average in 2016, 45% below average in 2017, and at or slightly below average in 2018 and 2019, respectively. Average May–September zooplankton density and biomass at Chilkoot Lake were nearly double the long-term average, and zooplankton density in 2019 and biomass in 2016 were the highest recorded since sampling began in 1987.
Author: Shelby M. Flemming
Publisher:
ISBN:
Category : Escapement (Fisheries)
Languages : en
Pages : 0
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Book Description
In 2020 and 2021, the Alaska Department of Fish and Game, Division of Commercial Fisheries, continued a stock assessment program that began in 1976 to estimate escapements and harvests of Chilkoot Lake sockeye salmon (Oncorhynchus nerka). Sockeye salmon were counted through a weir near the outlet of Chilkoot Lake, and age, length, and sex data were collected and analyzed each year. Sockeye salmon escapements at the weir were 60,218 fish in 2020 and 98,672 fish in 2021, which fell within or exceeded the sustainable escapement goal range of 38,000–86,000 fish. Age-1.2 male sockeye salmon in 2020 were larger than the 1982–2019 average, whereas both male and female fish of other ages fell below this average. Genetic stock identification was conducted to determine the stock composition of sockeye salmon harvested annually in the District 15 commercial drift gillnet fishery. Estimated commercial harvests of Chilkoot Lake sockeye salmon were 24,878 fish in 2020, and 50,219 fish in 2021. Estimated harvest rates (including subsistence and excluding sport harvests) were 32% in 2020 and 35% in 2021, and Chilkoot Lake sockeye salmon accounted for an estimated 50% (2020) and 59% (2021) of the annual commercial sockeye salmon harvest in District 15. The estimated fall sockeye salmon fry population at Chilkoot Lake was 66% below average in 2020 (no surveys were conducted in 2021). Average May–September zooplankton density and biomass at Chilkoot Lake were above average in 2020 and below average in 2021.
Author: Nicole L. Zeiser
Publisher:
ISBN:
Category : Escapement (Fisheries)
Languages : en
Pages : 48
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Book Description
The Chilkoot Lake sockeye salmon (Oncorhynchus nerka) run, which spawns near Haines, is one of the largest in Southeast Alaska and contributes substantially to harvests in the District 15 commercial drift gillnet fishery in Lynn Canal. This operational plan outlines objectives, methods, and timelines for conducting sockeye salmon stock assessment designed to (1) estimate annual escapement and harvest, (2) provide information for inseason fishery management, and (3) reconstruct runs and assess stock status. The Chilkoot Lake run is managed for a biological escapement goal of 38,000–86,000 fish, which is enumerated through a standard picket weir located just downstream of the lake outlet. Weir counts of sockeye salmon are compared to weekly escapement targets to determine inseason run strength. Genetic mixed stock analysis of weekly sockeye salmon harvests in the District 15 commercial drift gillnet fishery provides stock composition estimates that also guide inseason management of the fishery. Biological sampling, along with escapement enumeration and stock-specific harvest data, allows for total run reconstruction required for escapement goal review.
Author: Teresa M. Fish
Publisher:
ISBN:
Category : Escapement (Fisheries)
Languages : en
Pages : 0
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Book Description
In 2020, long-term population studies designed to evaluate adult sockeye salmon (Oncorhynchus nerka) abundance and juvenile production at Hugh Smith Lake continued. The smolt weir count of 16,000 sockeye salmon smolt was tied for the 2nd lowest count on record. An estimated 48% of smolt were freshwater age-1 and 52% were freshwater age-2. The escapement was counted through a weir, a mark–recapture study was conducted to confirm the weir count, and biological data were collected to estimate the age, length, and sex composition of the adult sockeye salmon escapement. The 2020 weir count of 3,860 adult sockeye salmon was below the optimal escapement goal range of 8,000–18,000 adult sockeye salmon and was the 9th lowest escapement since 1980. Age-2.2 fish were the most abundant age class, representing an estimated 40% of the total spawning population. Counts of live sockeye salmon in Buschmann Creek (not including mouth estimates) only exceeded 250 fish during 4 of 18 surveys from 19 August to 7 November (peak count 556 fish on 27 October). Counts of live sockeye salmon in Cobb Creek peaked at only 27 fish on 30 September and all other counts there were less than 20 fish. Reported subsistence harvest was 70 fish and accounted for an estimated 2% of the terminal run. The estimated minimum harvest rate in the District 101–108 commercial net fisheries was 38% in 2020.
Author: Mark J. Witteveen
Publisher:
ISBN:
Category : Escapement (Fisheries)
Languages : en
Pages : 0
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Book Description
The Alaska Department of Fish and Game, Division of Sport Fish, has assessed the annual run of Buskin River sockeye salmon (Oncorhynchus nerka) on Kodiak Island, Alaska, since 1990. Buskin River sockeye salmon weir counts were 4,284, 12,297, 7,741, and 2,330 fish for 2018–2021, respectively. Weir counts for Lake Louise were 83, 73, 53, and 1,896 sockeye salmon for 2018–2021, respectively. Reported annual subsistence harvests for the Buskin River Section were 474, 836, and 1,620 sockeye salmon for 2018–2020, respectively; accurate harvest is not available for 2021 at this time. In interviews conducted with 11 subsistence users in 2019, 100% reported that the Buskin River was a traditional fishing location, and 73% reported that they subsistence fished in other areas. Interviews were not conducted in 2018 due to a low run or in 2020 and 2021 due to COVID-19. Enumerated sockeye salmon spawning escapement for the entire drainage (Buskin Lake and Louise Lake weirs) was 4,367, 12,370, 7,794, and 4,226 fish for 2018–2021, respectively. Based on a Bayesian spawner–recruitment analysis of the Buskin Lake system, estimated spawning escapement for maximum sustained yield is about 5,700 fish (95% credibility interval = 4,300–8,000). A sustained yield probability analysis supports the current Buskin Lake system biological escapement goal (BEG) range of 5,000–8,000 sockeye salmon. Age-1.2, -1.3, -2.2, and -2.3 sockeye salmon composed 93–99% of the Buskin River run. Male to female ratios for the Buskin River were between 0.6 and 1.1 to 1 for 2018–2021. Samples taken from the Lake Louise sockeye salmon run and the subsistence harvest were too low to provide reliable estimates of age and sex composition.
