Walleye pollock respond to trawling vessels
Abstract The potential for fish to avoid survey vessels is a major source of uncertainty in stock-assessment surveys. Although walleye pollock (Theragra chalcogramma) are the subject of a substantial commercial fishery in the North Pacific, their behavioural responses to approaching survey vessels r...
Published in: | ICES Journal of Marine Science |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Oxford University Press (OUP)
2006
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1016/j.icesjms.2005.08.014 http://academic.oup.com/icesjms/article-pdf/63/3/514/29125145/63-3-514.pdf |
id |
croxfordunivpr:10.1016/j.icesjms.2005.08.014 |
---|---|
record_format |
openpolar |
spelling |
croxfordunivpr:10.1016/j.icesjms.2005.08.014 2024-06-23T07:51:46+00:00 Walleye pollock respond to trawling vessels De Robertis, Alex Wilson, Christopher D. 2006 http://dx.doi.org/10.1016/j.icesjms.2005.08.014 http://academic.oup.com/icesjms/article-pdf/63/3/514/29125145/63-3-514.pdf en eng Oxford University Press (OUP) ICES Journal of Marine Science volume 63, issue 3, page 514-522 ISSN 1095-9289 1054-3139 journal-article 2006 croxfordunivpr https://doi.org/10.1016/j.icesjms.2005.08.014 2024-06-04T06:12:07Z Abstract The potential for fish to avoid survey vessels is a major source of uncertainty in stock-assessment surveys. Although walleye pollock (Theragra chalcogramma) are the subject of a substantial commercial fishery in the North Pacific, their behavioural responses to approaching survey vessels remain poorly understood. As a first step in an effort to determine if walleye pollock avoid survey vessels engaged in trawling operations, we made pairwise comparisons of acoustic backscatter recorded by survey vessels while free-running and while trawling. Results are presented of acoustic backscatter recorded from NOAA's RV “Miller Freeman”, which used a midwater trawl during the 1996–2002 eastern Bering Sea surveys, and a chartered commercial fishing vessel, which used a bottom trawl during a survey in 2003 in the Gulf of Alaska. In both cases, average backscatter from a vessel-mounted echosounder was significantly higher when free-running than when trawling. These decreases in backscatter are consistent with increased vessel avoidance while trawling. There were no differences in the vertical distribution of backscatter when free-running and trawling, indicating that pollock do not exhibit elevated diving responses when approached by a trawling vessel rather than by a free-running vessel. Although the study indicates that pollock respond to trawling vessels, the nature of the behavioural response cannot be determined with the methods used in this study. Future work should evaluate potential stimuli produced by trawlers to which pollock may react, and should document changes in behaviour that may occur in their presence. Article in Journal/Newspaper Bering Sea Theragra chalcogramma Alaska Oxford University Press Bering Sea Gulf of Alaska Pacific ICES Journal of Marine Science 63 3 514 522 |
institution |
Open Polar |
collection |
Oxford University Press |
op_collection_id |
croxfordunivpr |
language |
English |
description |
Abstract The potential for fish to avoid survey vessels is a major source of uncertainty in stock-assessment surveys. Although walleye pollock (Theragra chalcogramma) are the subject of a substantial commercial fishery in the North Pacific, their behavioural responses to approaching survey vessels remain poorly understood. As a first step in an effort to determine if walleye pollock avoid survey vessels engaged in trawling operations, we made pairwise comparisons of acoustic backscatter recorded by survey vessels while free-running and while trawling. Results are presented of acoustic backscatter recorded from NOAA's RV “Miller Freeman”, which used a midwater trawl during the 1996–2002 eastern Bering Sea surveys, and a chartered commercial fishing vessel, which used a bottom trawl during a survey in 2003 in the Gulf of Alaska. In both cases, average backscatter from a vessel-mounted echosounder was significantly higher when free-running than when trawling. These decreases in backscatter are consistent with increased vessel avoidance while trawling. There were no differences in the vertical distribution of backscatter when free-running and trawling, indicating that pollock do not exhibit elevated diving responses when approached by a trawling vessel rather than by a free-running vessel. Although the study indicates that pollock respond to trawling vessels, the nature of the behavioural response cannot be determined with the methods used in this study. Future work should evaluate potential stimuli produced by trawlers to which pollock may react, and should document changes in behaviour that may occur in their presence. |
format |
Article in Journal/Newspaper |
author |
De Robertis, Alex Wilson, Christopher D. |
spellingShingle |
De Robertis, Alex Wilson, Christopher D. Walleye pollock respond to trawling vessels |
author_facet |
De Robertis, Alex Wilson, Christopher D. |
author_sort |
De Robertis, Alex |
title |
Walleye pollock respond to trawling vessels |
title_short |
Walleye pollock respond to trawling vessels |
title_full |
Walleye pollock respond to trawling vessels |
title_fullStr |
Walleye pollock respond to trawling vessels |
title_full_unstemmed |
Walleye pollock respond to trawling vessels |
title_sort |
walleye pollock respond to trawling vessels |
publisher |
Oxford University Press (OUP) |
publishDate |
2006 |
url |
http://dx.doi.org/10.1016/j.icesjms.2005.08.014 http://academic.oup.com/icesjms/article-pdf/63/3/514/29125145/63-3-514.pdf |
geographic |
Bering Sea Gulf of Alaska Pacific |
geographic_facet |
Bering Sea Gulf of Alaska Pacific |
genre |
Bering Sea Theragra chalcogramma Alaska |
genre_facet |
Bering Sea Theragra chalcogramma Alaska |
op_source |
ICES Journal of Marine Science volume 63, issue 3, page 514-522 ISSN 1095-9289 1054-3139 |
op_doi |
https://doi.org/10.1016/j.icesjms.2005.08.014 |
container_title |
ICES Journal of Marine Science |
container_volume |
63 |
container_issue |
3 |
container_start_page |
514 |
op_container_end_page |
522 |
_version_ |
1802642897908006912 |