Effects of simulated trawling on sablefish and walleye pollock: the role of light intensity, net velocity and towing duration
Laboratory apparatus which simulated capture of fish in the cod‐end of a towed trawl was used to induce post‐capture stress as measured by alterations in behavioural, physiological and mortality indices in juvenile walleye pollock Theragra chalcogramma and juvenile and adult sablefish Anoplopoma fim...
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1997
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Online Access: | http://dx.doi.org/10.1111/j.1095-8649.1997.tb01646.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1997.tb01646.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1997.tb01646.x |
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crwiley:10.1111/j.1095-8649.1997.tb01646.x 2024-06-02T08:15:15+00:00 Effects of simulated trawling on sablefish and walleye pollock: the role of light intensity, net velocity and towing duration Olla, B. L. Davis, M. W. Schreck, C. B. 1997 http://dx.doi.org/10.1111/j.1095-8649.1997.tb01646.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1997.tb01646.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1997.tb01646.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Fish Biology volume 50, issue 6, page 1181-1194 ISSN 0022-1112 1095-8649 journal-article 1997 crwiley https://doi.org/10.1111/j.1095-8649.1997.tb01646.x 2024-05-03T11:56:13Z Laboratory apparatus which simulated capture of fish in the cod‐end of a towed trawl was used to induce post‐capture stress as measured by alterations in behavioural, physiological and mortality indices in juvenile walleye pollock Theragra chalcogramma and juvenile and adult sablefish Anoplopoma fimbria . Differences in resistance to net entrainment varied between species with the severity of stress and the potential for recovery depending on light intensity, net velocity and towing duration. At a light intensity which simulated daylight at depth in clear ocean water (0.5 μmol photons m −2 s −1 ), walleye pollock juveniles were able to maintain swimming in nets towed at 0.65 m s −1 for 3h with no discernible effects on behaviour or mortality. However, when net velocity was increased to >0.75m s −1 or light intensity was decreased to <0.002 μmol photons m −2 s −1 , fish became entrained in the meshes of the net and exhibited significant alterations in feeding behaviour, predator evasion and increases in plasma cortisol concentrations. Marked increases in stress‐induced mortality also occurred, in some cases after a delay of 6 days and eventually reaching 100%. In comparison with walleye pollock, sablefish juveniles became entrained in the meshes of the net at higher velocities (>0.92m s −1 ) or lower light intensities (<0.0004 μmol photons m −2 s −1 ) and were much more resistant to post‐capture stress. Towing of net‐entrained fish for 15 min caused no detectable changes in feeding and cortisol and for 2 h, no changes in feeding although mortality increased from 0% for 15‐min tows to 19% for 2‐h tows. Towing for 4 h caused significant alterations in feeding and cortisol with feeding recovering to control levels by 6 days and cortisol by 3 days; mortality was 25%. When adult sablefish were towed for 4 h followed by 15‐min exposure to air, feeding was inhibited 6 days after towing, but recovered within 30 days with no mortality observed after 30 days. The results demonstrate the value of using ... Article in Journal/Newspaper Theragra chalcogramma Wiley Online Library Journal of Fish Biology 50 6 1181 1194 |
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Wiley Online Library |
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crwiley |
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English |
description |
Laboratory apparatus which simulated capture of fish in the cod‐end of a towed trawl was used to induce post‐capture stress as measured by alterations in behavioural, physiological and mortality indices in juvenile walleye pollock Theragra chalcogramma and juvenile and adult sablefish Anoplopoma fimbria . Differences in resistance to net entrainment varied between species with the severity of stress and the potential for recovery depending on light intensity, net velocity and towing duration. At a light intensity which simulated daylight at depth in clear ocean water (0.5 μmol photons m −2 s −1 ), walleye pollock juveniles were able to maintain swimming in nets towed at 0.65 m s −1 for 3h with no discernible effects on behaviour or mortality. However, when net velocity was increased to >0.75m s −1 or light intensity was decreased to <0.002 μmol photons m −2 s −1 , fish became entrained in the meshes of the net and exhibited significant alterations in feeding behaviour, predator evasion and increases in plasma cortisol concentrations. Marked increases in stress‐induced mortality also occurred, in some cases after a delay of 6 days and eventually reaching 100%. In comparison with walleye pollock, sablefish juveniles became entrained in the meshes of the net at higher velocities (>0.92m s −1 ) or lower light intensities (<0.0004 μmol photons m −2 s −1 ) and were much more resistant to post‐capture stress. Towing of net‐entrained fish for 15 min caused no detectable changes in feeding and cortisol and for 2 h, no changes in feeding although mortality increased from 0% for 15‐min tows to 19% for 2‐h tows. Towing for 4 h caused significant alterations in feeding and cortisol with feeding recovering to control levels by 6 days and cortisol by 3 days; mortality was 25%. When adult sablefish were towed for 4 h followed by 15‐min exposure to air, feeding was inhibited 6 days after towing, but recovered within 30 days with no mortality observed after 30 days. The results demonstrate the value of using ... |
format |
Article in Journal/Newspaper |
author |
Olla, B. L. Davis, M. W. Schreck, C. B. |
spellingShingle |
Olla, B. L. Davis, M. W. Schreck, C. B. Effects of simulated trawling on sablefish and walleye pollock: the role of light intensity, net velocity and towing duration |
author_facet |
Olla, B. L. Davis, M. W. Schreck, C. B. |
author_sort |
Olla, B. L. |
title |
Effects of simulated trawling on sablefish and walleye pollock: the role of light intensity, net velocity and towing duration |
title_short |
Effects of simulated trawling on sablefish and walleye pollock: the role of light intensity, net velocity and towing duration |
title_full |
Effects of simulated trawling on sablefish and walleye pollock: the role of light intensity, net velocity and towing duration |
title_fullStr |
Effects of simulated trawling on sablefish and walleye pollock: the role of light intensity, net velocity and towing duration |
title_full_unstemmed |
Effects of simulated trawling on sablefish and walleye pollock: the role of light intensity, net velocity and towing duration |
title_sort |
effects of simulated trawling on sablefish and walleye pollock: the role of light intensity, net velocity and towing duration |
publisher |
Wiley |
publishDate |
1997 |
url |
http://dx.doi.org/10.1111/j.1095-8649.1997.tb01646.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1997.tb01646.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1997.tb01646.x |
genre |
Theragra chalcogramma |
genre_facet |
Theragra chalcogramma |
op_source |
Journal of Fish Biology volume 50, issue 6, page 1181-1194 ISSN 0022-1112 1095-8649 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1095-8649.1997.tb01646.x |
container_title |
Journal of Fish Biology |
container_volume |
50 |
container_issue |
6 |
container_start_page |
1181 |
op_container_end_page |
1194 |
_version_ |
1800739360186826752 |