Walleye Pollock (Theragra Chalcogramma) Distribution In The Eastern Bering Sea Related To Fishery And Environmental Factors
Dissertation (Ph.D.) University of Alaska Fairbanks, 2009 Walleye pollock (Theragra chalcogramma) in the eastern Bering Sea (EBS) support the largest single-species fishery in the world. Pollock also play an important role in the EBS ecosystem as an important prey species. The decline of the western...
Main Author: | |
---|---|
Format: | Doctoral or Postdoctoral Thesis |
Language: | unknown |
Published: |
2009
|
Subjects: | |
Online Access: | http://hdl.handle.net/11122/9018 |
id |
ftunivalaska:oai:scholarworks.alaska.edu:11122/9018 |
---|---|
record_format |
openpolar |
spelling |
ftunivalaska:oai:scholarworks.alaska.edu:11122/9018 2023-05-15T15:43:41+02:00 Walleye Pollock (Theragra Chalcogramma) Distribution In The Eastern Bering Sea Related To Fishery And Environmental Factors Shen, Haixue 2009 http://hdl.handle.net/11122/9018 unknown http://hdl.handle.net/11122/9018 Fisheries Division Aquatic sciences Dissertation phd 2009 ftunivalaska 2023-02-23T21:37:11Z Dissertation (Ph.D.) University of Alaska Fairbanks, 2009 Walleye pollock (Theragra chalcogramma) in the eastern Bering Sea (EBS) support the largest single-species fishery in the world. Pollock also play an important role in the EBS ecosystem as an important prey species. The decline of the western population of Steller sea lions during the 1980s and 1990s raised concerns about the potential competition between the pollock fishery and the sea lion population. My research focused on pollock distribution related to the fishery and physical environment at different temporal and spatial scales using fisheries acoustic data and observer data in the winter fishing season during 2002-2006. Temperature and wind played important roles in determining the pollock distribution in winter, especially from late February to March. The changes in spatial structure during the fishing season suggested that the fishery probably influenced pollock distribution by removing some portion of the local population and perhaps even smoothing out the aggregated distribution of pollock. At a small scale, pollock schools became smaller and denser. At the meso-scale, the distances between schools increased. At a larger scale, range estimates from variography increased which indicated that the spatial correlation among pollock extended to greater distances after fishing. Fishing behavior was also studied using Levy flight theory and its relation to pollock distribution in the EBS. Fishing behavior was significantly correlated to the fractal dimension of fish which measures the degree of pollock clustering, rather than to pollock spatial concentration or density in the EBS. The observer data were also included to analyze the effect of fish distribution on fishing behavior at the school scale. The results indicated that school density rather than the school size played an important role in fishing behavior. Finally, catch depletion analysis was used to examine the potential local depletion. While frequentist and Bayesian methods confirmed that ... Doctoral or Postdoctoral Thesis Bering Sea Theragra chalcogramma Alaska University of Alaska: ScholarWorks@UA Bering Sea Fairbanks Levy ENVELOPE(-66.567,-66.567,-66.320,-66.320) |
institution |
Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
unknown |
topic |
Aquatic sciences |
spellingShingle |
Aquatic sciences Shen, Haixue Walleye Pollock (Theragra Chalcogramma) Distribution In The Eastern Bering Sea Related To Fishery And Environmental Factors |
topic_facet |
Aquatic sciences |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 2009 Walleye pollock (Theragra chalcogramma) in the eastern Bering Sea (EBS) support the largest single-species fishery in the world. Pollock also play an important role in the EBS ecosystem as an important prey species. The decline of the western population of Steller sea lions during the 1980s and 1990s raised concerns about the potential competition between the pollock fishery and the sea lion population. My research focused on pollock distribution related to the fishery and physical environment at different temporal and spatial scales using fisheries acoustic data and observer data in the winter fishing season during 2002-2006. Temperature and wind played important roles in determining the pollock distribution in winter, especially from late February to March. The changes in spatial structure during the fishing season suggested that the fishery probably influenced pollock distribution by removing some portion of the local population and perhaps even smoothing out the aggregated distribution of pollock. At a small scale, pollock schools became smaller and denser. At the meso-scale, the distances between schools increased. At a larger scale, range estimates from variography increased which indicated that the spatial correlation among pollock extended to greater distances after fishing. Fishing behavior was also studied using Levy flight theory and its relation to pollock distribution in the EBS. Fishing behavior was significantly correlated to the fractal dimension of fish which measures the degree of pollock clustering, rather than to pollock spatial concentration or density in the EBS. The observer data were also included to analyze the effect of fish distribution on fishing behavior at the school scale. The results indicated that school density rather than the school size played an important role in fishing behavior. Finally, catch depletion analysis was used to examine the potential local depletion. While frequentist and Bayesian methods confirmed that ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Shen, Haixue |
author_facet |
Shen, Haixue |
author_sort |
Shen, Haixue |
title |
Walleye Pollock (Theragra Chalcogramma) Distribution In The Eastern Bering Sea Related To Fishery And Environmental Factors |
title_short |
Walleye Pollock (Theragra Chalcogramma) Distribution In The Eastern Bering Sea Related To Fishery And Environmental Factors |
title_full |
Walleye Pollock (Theragra Chalcogramma) Distribution In The Eastern Bering Sea Related To Fishery And Environmental Factors |
title_fullStr |
Walleye Pollock (Theragra Chalcogramma) Distribution In The Eastern Bering Sea Related To Fishery And Environmental Factors |
title_full_unstemmed |
Walleye Pollock (Theragra Chalcogramma) Distribution In The Eastern Bering Sea Related To Fishery And Environmental Factors |
title_sort |
walleye pollock (theragra chalcogramma) distribution in the eastern bering sea related to fishery and environmental factors |
publishDate |
2009 |
url |
http://hdl.handle.net/11122/9018 |
long_lat |
ENVELOPE(-66.567,-66.567,-66.320,-66.320) |
geographic |
Bering Sea Fairbanks Levy |
geographic_facet |
Bering Sea Fairbanks Levy |
genre |
Bering Sea Theragra chalcogramma Alaska |
genre_facet |
Bering Sea Theragra chalcogramma Alaska |
op_relation |
http://hdl.handle.net/11122/9018 Fisheries Division |
_version_ |
1766377880191762432 |