タイトル |
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en
The influence of warp length on trawl dimension and catch of walleye pollock Theragra chalcogramma in a bottom trawl survey
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ja
スケトウダラ着底トロール調査におけるワープ長の違いが網形状と漁獲に与える影響
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作成者 |
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アクセス権 |
open access |
権利情報 |
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ja
© 2005 公益社団法人日本水産学会
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en
© 2005 The Japanese Society of Fisheries Science
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主題 |
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Other
en
footgear contact
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Other
en
trawl dimension
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Other
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trawl survey
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Other
en
walleye pollock
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Other
en
warp length
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NDC
664
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内容注記 |
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Abstract
en
We examined variation in trawl dimension, bottom contact, and catch with differing warp lengths during walleye pollock surveys conducted by the Fisheries Research Agency. The ratio of warp length to fishing depth (scope ratio) was set at 2.5, 3.0 and 3.5 at depths of 110 m. At a 2.5 scope ratio, the net mouth shape and footgear contact fluctuated, as the trawl door did not contact the bottom. Footgear contact was complete when the scope ratio was 3.0 or more. Walleye pollock, sculpins, and flatfishes were the main catch in all tows, and the catch increased with scope ratio. There was no difference in the length frequency of n= 300 walleye pollock captured at 2.5 and 3.0 scope ratio. However, the length frequency at 3.5 was significantly different from that of other scope ratios. These results suggest the following: at a scope ratio of 3.0 or more, the trawl door will not leave the bottom at any depths. To compliment echo surveys for walleye pollock, a 3.0 scope ratio would be optimal, since the catch data for a 3.5 scope ratio was dissimilar from that of scope ratios.
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出版者 |
en
Blackwell Publishing
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日付 |
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言語 |
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資源タイプ |
journal article |
出版タイプ |
AM |
資源識別子 |
HDL
http://hdl.handle.net/2115/623
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関連 |
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isVersionOf
DOI
https://doi.org/10.1111/j.1444-2906.2005.01023.x
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収録誌情報 |
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en
Fisheries Science
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巻71
号4
開始ページ738
終了ページ747
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ファイル |
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fulltext
trawl.zip
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401.86 KB
(application/zip)
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コンテンツ更新日時 |
2023-07-26 |