Adaptive cluster sampling of Gulf of Alaska rockfish
Thesis (M.S.) University of Alaska Fairbanks, 2000 National Marine Fisheries Service trawl surveys result in more variable biomass estimates for long-lived Gulf of Alaska rockfish than researchers expect. Adaptive cluster sampling (ACS) was investigated to improve these surveys. In August 1998 east...
Main Author: | |
---|---|
Format: | Thesis |
Language: | English |
Published: |
2000
|
Subjects: | |
Online Access: | http://hdl.handle.net/11122/6774 |
id |
ftunivalaska:oai:scholarworks.alaska.edu:11122/6774 |
---|---|
record_format |
openpolar |
spelling |
ftunivalaska:oai:scholarworks.alaska.edu:11122/6774 2023-05-15T17:04:38+02:00 Adaptive cluster sampling of Gulf of Alaska rockfish Hanselman, Dana Henry 2000-08 http://hdl.handle.net/11122/6774 en_US eng http://hdl.handle.net/11122/6774 Fisheries Division Thesis ms 2000 ftunivalaska 2023-02-23T21:36:43Z Thesis (M.S.) University of Alaska Fairbanks, 2000 National Marine Fisheries Service trawl surveys result in more variable biomass estimates for long-lived Gulf of Alaska rockfish than researchers expect. Adaptive cluster sampling (ACS) was investigated to improve these surveys. In August 1998 east of Kodiak, AK, a sampling cruise tested ACS for Pacific ocean perch (POP), and shortraker and rougheye rockfish (SR/RE). In each of six strata, simple random sampling was conducted, then ACS was performed on top stations. Stopping rules prevented sampling from continuing indefinitely. Results did not resolve whether ACS alone was better than simple random sampling. ACS, combined with stratification, increased precision of POP estimates by 30% over random sampling, suggesting that the spatial distribution has both fine-scale and habitat-scale patterns. Variograms indicated that the expected aggregation was not encountered for POP, but that POP are more aggregated than SR/RE. Some diel movement of POP was evident. Both species were concentrated at specific depths. Thesis Kodiak Alaska University of Alaska: ScholarWorks@UA Fairbanks Gulf of Alaska Pacific |
institution |
Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
English |
description |
Thesis (M.S.) University of Alaska Fairbanks, 2000 National Marine Fisheries Service trawl surveys result in more variable biomass estimates for long-lived Gulf of Alaska rockfish than researchers expect. Adaptive cluster sampling (ACS) was investigated to improve these surveys. In August 1998 east of Kodiak, AK, a sampling cruise tested ACS for Pacific ocean perch (POP), and shortraker and rougheye rockfish (SR/RE). In each of six strata, simple random sampling was conducted, then ACS was performed on top stations. Stopping rules prevented sampling from continuing indefinitely. Results did not resolve whether ACS alone was better than simple random sampling. ACS, combined with stratification, increased precision of POP estimates by 30% over random sampling, suggesting that the spatial distribution has both fine-scale and habitat-scale patterns. Variograms indicated that the expected aggregation was not encountered for POP, but that POP are more aggregated than SR/RE. Some diel movement of POP was evident. Both species were concentrated at specific depths. |
format |
Thesis |
author |
Hanselman, Dana Henry |
spellingShingle |
Hanselman, Dana Henry Adaptive cluster sampling of Gulf of Alaska rockfish |
author_facet |
Hanselman, Dana Henry |
author_sort |
Hanselman, Dana Henry |
title |
Adaptive cluster sampling of Gulf of Alaska rockfish |
title_short |
Adaptive cluster sampling of Gulf of Alaska rockfish |
title_full |
Adaptive cluster sampling of Gulf of Alaska rockfish |
title_fullStr |
Adaptive cluster sampling of Gulf of Alaska rockfish |
title_full_unstemmed |
Adaptive cluster sampling of Gulf of Alaska rockfish |
title_sort |
adaptive cluster sampling of gulf of alaska rockfish |
publishDate |
2000 |
url |
http://hdl.handle.net/11122/6774 |
geographic |
Fairbanks Gulf of Alaska Pacific |
geographic_facet |
Fairbanks Gulf of Alaska Pacific |
genre |
Kodiak Alaska |
genre_facet |
Kodiak Alaska |
op_relation |
http://hdl.handle.net/11122/6774 Fisheries Division |
_version_ |
1766058944041582592 |