Quantification and reduction of unobserved mortality rates for snow, southern Tanner, and red king crabs (Chionoecetes opilio, C. bairdi, and Paralithodes camtschaticus) after encounters with trawls on the seafloor
Unobserved mortalities of nontarget species are among the most troubling and difficult issues associated with fishing, especially when those species are targeted by other fisheries. Of such concern are mortalities of crab species of the Bering Sea, which are exposed to bottom trawling from groundfis...
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Online Access: | http://hdl.handle.net/1834/30356 https://doi.org/10.7755/FB.111.1.4 |
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ftoceandocs:oai:aquadocs.org:1834/30356 2023-05-15T15:43:56+02:00 Quantification and reduction of unobserved mortality rates for snow, southern Tanner, and red king crabs (Chionoecetes opilio, C. bairdi, and Paralithodes camtschaticus) after encounters with trawls on the seafloor Rose, Craig S. Hammond, Carwyn F. Stoner, Allan W. Munk, J. Eric Gauvin, John R. 2013 application/pdf 42-53 http://hdl.handle.net/1834/30356 https://doi.org/10.7755/FB.111.1.4 en eng http://fishbull.noaa.gov/1111/rose.pdf 0090-0656 doi:10.7755/FB.111.1.4 http://hdl.handle.net/1834/30356 craig.rose@noaa.gov http://aquaticcommons.org/id/eprint/14493 403 2014-02-13 04:23:34 14493 United States National Marine Fisheries Service Biology Ecology Fisheries article TRUE 2013 ftoceandocs https://doi.org/10.7755/FB.111.1.4 2023-04-06T17:04:08Z Unobserved mortalities of nontarget species are among the most troubling and difficult issues associated with fishing, especially when those species are targeted by other fisheries. Of such concern are mortalities of crab species of the Bering Sea, which are exposed to bottom trawling from groundfish fisheries. Uncertainty in the management of these fisheries has been exacerbated by unknown mortality rates for crabs struck by trawls. In this study, the mortality rates for 3 species of commercially important crabs—red king crab, (Paralithodes camtschaticus), snow crab (Chionoecetes opilio) and southern Tanner crab (C. bairdi)—that encounter different components of bottom trawls were estimated through capture of crabs behind the bottom trawl and by evaluation of immediate and delayed mortalities. We used a reflex action mortality predictor to predict delayed mortalities. Estimated mortality rates varied by species and by the part of the trawl gear encountered. Red king crab were more vulnerable than snow or southern Tanner crabs. Crabs were more likely to die after encountering the footrope than the sweeps of the trawl, and higher death rates were noted for the side sections of the footrope than for the center footrope section. Mortality rates were ≤16%, except for red king crab that passed under the trawl wings (32%). Herding devices (sweeps) can expand greatly the area of seafloor from which flatfishes are captured, and they subject crabs in that additional area to lower (4–9%) mortality rates. Raising sweep cables off of the seafloor reduced red king crab mortality rates from 10% to 4%. Article in Journal/Newspaper Bering Sea Chionoecetes opilio Paralithodes camtschaticus Red king crab Snow crab Tanner crab IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications Bering Sea Fishery Bulletin 111 1 |
institution |
Open Polar |
collection |
IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications |
op_collection_id |
ftoceandocs |
language |
English |
topic |
Biology Ecology Fisheries |
spellingShingle |
Biology Ecology Fisheries Rose, Craig S. Hammond, Carwyn F. Stoner, Allan W. Munk, J. Eric Gauvin, John R. Quantification and reduction of unobserved mortality rates for snow, southern Tanner, and red king crabs (Chionoecetes opilio, C. bairdi, and Paralithodes camtschaticus) after encounters with trawls on the seafloor |
topic_facet |
Biology Ecology Fisheries |
description |
Unobserved mortalities of nontarget species are among the most troubling and difficult issues associated with fishing, especially when those species are targeted by other fisheries. Of such concern are mortalities of crab species of the Bering Sea, which are exposed to bottom trawling from groundfish fisheries. Uncertainty in the management of these fisheries has been exacerbated by unknown mortality rates for crabs struck by trawls. In this study, the mortality rates for 3 species of commercially important crabs—red king crab, (Paralithodes camtschaticus), snow crab (Chionoecetes opilio) and southern Tanner crab (C. bairdi)—that encounter different components of bottom trawls were estimated through capture of crabs behind the bottom trawl and by evaluation of immediate and delayed mortalities. We used a reflex action mortality predictor to predict delayed mortalities. Estimated mortality rates varied by species and by the part of the trawl gear encountered. Red king crab were more vulnerable than snow or southern Tanner crabs. Crabs were more likely to die after encountering the footrope than the sweeps of the trawl, and higher death rates were noted for the side sections of the footrope than for the center footrope section. Mortality rates were ≤16%, except for red king crab that passed under the trawl wings (32%). Herding devices (sweeps) can expand greatly the area of seafloor from which flatfishes are captured, and they subject crabs in that additional area to lower (4–9%) mortality rates. Raising sweep cables off of the seafloor reduced red king crab mortality rates from 10% to 4%. |
format |
Article in Journal/Newspaper |
author |
Rose, Craig S. Hammond, Carwyn F. Stoner, Allan W. Munk, J. Eric Gauvin, John R. |
author_facet |
Rose, Craig S. Hammond, Carwyn F. Stoner, Allan W. Munk, J. Eric Gauvin, John R. |
author_sort |
Rose, Craig S. |
title |
Quantification and reduction of unobserved mortality rates for snow, southern Tanner, and red king crabs (Chionoecetes opilio, C. bairdi, and Paralithodes camtschaticus) after encounters with trawls on the seafloor |
title_short |
Quantification and reduction of unobserved mortality rates for snow, southern Tanner, and red king crabs (Chionoecetes opilio, C. bairdi, and Paralithodes camtschaticus) after encounters with trawls on the seafloor |
title_full |
Quantification and reduction of unobserved mortality rates for snow, southern Tanner, and red king crabs (Chionoecetes opilio, C. bairdi, and Paralithodes camtschaticus) after encounters with trawls on the seafloor |
title_fullStr |
Quantification and reduction of unobserved mortality rates for snow, southern Tanner, and red king crabs (Chionoecetes opilio, C. bairdi, and Paralithodes camtschaticus) after encounters with trawls on the seafloor |
title_full_unstemmed |
Quantification and reduction of unobserved mortality rates for snow, southern Tanner, and red king crabs (Chionoecetes opilio, C. bairdi, and Paralithodes camtschaticus) after encounters with trawls on the seafloor |
title_sort |
quantification and reduction of unobserved mortality rates for snow, southern tanner, and red king crabs (chionoecetes opilio, c. bairdi, and paralithodes camtschaticus) after encounters with trawls on the seafloor |
publishDate |
2013 |
url |
http://hdl.handle.net/1834/30356 https://doi.org/10.7755/FB.111.1.4 |
geographic |
Bering Sea |
geographic_facet |
Bering Sea |
genre |
Bering Sea Chionoecetes opilio Paralithodes camtschaticus Red king crab Snow crab Tanner crab |
genre_facet |
Bering Sea Chionoecetes opilio Paralithodes camtschaticus Red king crab Snow crab Tanner crab |
op_source |
craig.rose@noaa.gov http://aquaticcommons.org/id/eprint/14493 403 2014-02-13 04:23:34 14493 United States National Marine Fisheries Service |
op_relation |
http://fishbull.noaa.gov/1111/rose.pdf 0090-0656 doi:10.7755/FB.111.1.4 http://hdl.handle.net/1834/30356 |
op_doi |
https://doi.org/10.7755/FB.111.1.4 |
container_title |
Fishery Bulletin |
container_volume |
111 |
container_issue |
1 |
_version_ |
1766378150561841152 |