Factors Influencing Chinook Salmon Spawning Distribution in the Togiak River, Alaska PDF Download
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Author: Stephanie L. Meggers
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 148
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Book Description
Salmonids are heavily dependent on specific habitat characteristics for survival, yet few studies in Alaska have examined the relationship between habitat and spawning distribution, using remote sensing approaches. To better understand the relationship between Chinook Salmon Oncorhynchus tshawytscha spawning distribution and environmental variables like habitat type (e.g., run, riffle, pool), temperature, and proximity to channel islands, optical and thermal imagery were collected on the Togiak and Ongivinuk rivers in southwest Alaska. Object-based image analysis was used to classify and quantify habitat types, while thermal characteristics and the proximity of spawning locations to channel islands were determined in a GIS framework. Object-based image analysis was useful for classifying habitat and may provide a better alternative to pixel-based image analysis. However, rule sets were nontransferable and inconsistent among river reaches, and caution should be taken when these methods are used on large river sections. Chinook Salmon showed a preference for spawning in river runs, 80% of fish spawned in water temperatures between 8.6° and 9.4°C, and nearly 61% of Chinook Salmon spawned within 100 m of a channel island. This study provided a baseline understanding of environmental correlates of spawning for Chinook Salmon at the northern extent of their range.
Author: Stephanie L. Meggers
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 148
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Book Description
Salmonids are heavily dependent on specific habitat characteristics for survival, yet few studies in Alaska have examined the relationship between habitat and spawning distribution, using remote sensing approaches. To better understand the relationship between Chinook Salmon Oncorhynchus tshawytscha spawning distribution and environmental variables like habitat type (e.g., run, riffle, pool), temperature, and proximity to channel islands, optical and thermal imagery were collected on the Togiak and Ongivinuk rivers in southwest Alaska. Object-based image analysis was used to classify and quantify habitat types, while thermal characteristics and the proximity of spawning locations to channel islands were determined in a GIS framework. Object-based image analysis was useful for classifying habitat and may provide a better alternative to pixel-based image analysis. However, rule sets were nontransferable and inconsistent among river reaches, and caution should be taken when these methods are used on large river sections. Chinook Salmon showed a preference for spawning in river runs, 80% of fish spawned in water temperatures between 8.6° and 9.4°C, and nearly 61% of Chinook Salmon spawned within 100 m of a channel island. This study provided a baseline understanding of environmental correlates of spawning for Chinook Salmon at the northern extent of their range.
Author: Cheryl A. Anderson
Publisher:
ISBN:
Category : Animal radio tracking
Languages : en
Pages : 22
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Author: U.S. Fish and Wildlife Service. Anchorage Fish and Wildlife Field Office
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 36
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Author: Charles O. Junge
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 40
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Author: Jack M. Van Hyning
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 848
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A study of the population ecology of Columbia River fall chinook salmon, Oncorhynchus tshawytscha (Walbaum), was made in an attempt to determine the cause of a serious decline in this run which occurred in the early 1950's. Fluctuations in abundance of major salmon runs the North Pacific were examined to detect any coastwide pattern. Only chinook salmon in Cook Inlet, Alaska, and chum salmon from Oregon to southwestern Alaska showed a similar trend. The following life history stages broken down into pre- and post-decline years were examined: (1) marine life including distribution and migration, growth and maturity, survival rate, oceanography, and commercial and sport fisheries; (2) upstream migration including river fisheries, gear selectivity, size and age composition of the run, escapement, and influence of dams, diseases, and water quality; (3) reproduction and incubation including spawning areas and spawning and incubation conditions; and (4) downstream migration which included predation, dams and reservoirs, diseases, flow, turbidity and temperature, and estuary life. Salient points of the analysis were: (1) a change in the maturity and survival pattern based on tagged and fin-clipped fish recovered before and after 1950; (2) a significant negative correlation between sea-water temperature during a year class' first year at sea and subsequent survival; (3) a large increase in the ocean fisheries coincident with the decline in the run; (4) catch-effort statistics of the ocean fishery show a near classic example of the effect of overexploitation; (5) estimates of the contribution of Columbia River chinook to the ocean fisheries based on tag recoveries could be underestimates rather than overestimates; (6) a significant inverse correlation between estimated ocean catch of Columbia River fall chinook and numbers entering the river; (7) size and age composition of the ocean and river catches decreased coincident with the decline in the run; (8) the gill-net fishery shows little size selectivity by age, size, or sex in the dominant group; (9) fluctuations in abundance of hatchery stocks are related to differences in survival between fingerling and adult; (10) hatchery, lower river, and upriver populations fluctuate in abundance in much the same pattern; (11) optimum escapement is between 90,000 and 100,000 adults, a value that was exceeded during most years; (12) a highly significant negative correlation between numbers of spawners and return per spawner; (13) most of the early dams had no direct effect on fall chinook and the decline in productivity occurred when river conditions were relatively stable; (14) temperatures at time of migration and spawning for fall chinook have not increased enough to be a serious mortality factor; (15) little relationship between flow, turbidity, and temperature at time of downstream migration and subsequent return was evident except that high temperatures and high flows (and turbidities) tended to produce poorer runs during certain time periods; and (16) predation and delay of smolts in reservoirs are largely unknown factors, but circumstantial evidence suggests that they were not important in regulating fall chinook numbers during the period of the study. Finally, variables that appeared to bear some relationship to fluctuations in abundance of fall chinook were submitted to multiple regression analysis. For the predecline period (1938-46 brood years), sea-water temperature and ocean troll fishing effort were significant variables (R2 = 0.74). For post decline years (1947-59 broods), troll had the most influence on total return with ocean temperature and escapement having lesser effects. For the combined years, troll intensity and ocean temperature were the significant variables (R2 = 0.572). Entering interaction of river flow at downstream migration with the other variables brought R2 to 0.754 which means that 75% of the variability in the returning run could be accounted for by these three factors. Return per spawner was so heavily influenced by numbers of spawners that the other factors assumed negligible importance. Equations were derived that predicted the returning run in close agreement with the actual run size. Substituting a low and constant troll fishing effort in the equation resulted in the predicted run maintaining the average predecline level. The increase in ocean fishing was the main contributor to the decline of the Columbia River fall chinook run as shown by correlation, by analogy, and by the process of elimination. To demonstrate why other chinook runs have not shown similar declines, it was shown that due to several unique features in Columbia River fall chinook life history they are exposed to much more ocean fishing than other populations. It was emphasized that these conclusions should not be extrapolated to the future or to other species or runs of salmon.
Author: Robert Glenn Kope
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 252
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Author: Olivia N. Edwards
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 0
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Chinook Salmon Oncorhynchus tshawytscha have experienced population declines across their range in recent decades, including Alaska where they are a critical subsistence, commercial, and sport fish species. The Alaska Board of Fisheries has listed Yukon River Chinook salmon as a “stock of yield concern” since 2000 prompting the implementation of escapement goals for key spawning tributaries in 2001. Additionally, research efforts across the basin have increased to better understand potential mechanisms behind these declines and provide information to facilitate management decisions. To help fill a critical data gap in the overall understanding of the fishery, this research investigated various freshwater juvenile life history factors including patterns in post-emergence summer body size, movement, and fish size during spring outmigration in the Chena River, Alaska. This research also identified links between these biological factors and freshwater processes that are affected by climate change, including stream temperature and discharge, with the intention of documenting benchmark information as conditions continue to change. Juvenile Chinook Salmon movement among four key rearing areas was observed during summer and fall 2019 and early spring 2020. Despite differences in early summer size patterns, by the end of September mean fork lengths were not statistically different among all rearing areas (ANOVA; all P > 0.05). Additionally, mean September weight varied among six years of empirical data and ranged from 3.19 g in 2018 (0.03 SE) to a maximum of 5.10 g in 2009 (0.05 SE). September weight was simulated across years with variable stream temperatures and discharge (2003 to 2020) using a bioenergetics model, and compared to observed data. Weight simulations were within
Author: Richard Yanusz
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 40
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The purpose of this study is to determine the spawning distribution of chinook salmon in the Susitna drainage upstream of the confluence with the Yentna River as well as the spawning distribution of pink salmon in the entire Susitna drainage. The information collected during the 2012 field season will be used to address the feasibility of conducting a basin-wide capture-recapture study of chinook salmon in 2013 and 2014.
Author: Deena M. Jallen
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 182
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"Chinook salmon Oncorhynchus tshawytscha are a highly valued traditional, subsistence, and commercial resource in southwest Alaska. Stream habitat availability is a major component influencing salmon productivity. The objective of this study is to identify river features associated with spawning habitat, and describe upper and lower boundaries of Chinook salmon spawning on the Tuluksak River. River distances, elevation, salmon locations, spawning sites, and habitat observations were collected along 75 rkm (river kilometers) of the Tuluksak River primarily within the Yukon Delta National Wildlife Refuge. Habitat and salmon observations were grouped into strata along the length of the river for comparison and analysis. Chinook salmon were observed spawning in the upper 45 rkm of the study area. Map-based observations of elevation and channel sinuosity correlate better with Chinook salmon spawning than in stream habitat measurements along the Tuluksak River. The upper boundary of Chinook salmon spawning in the Tuluksak River was outside of our study area. The lower boundary for Chinook salmon spawning habitat on similar rivers might be determined by examining elevation, sinuosity, and channel features from remote images or maps prior to conducting field studies"--Leaf iii.
Author: Philip John Joy
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 42
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