Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index
Millions of crabs are sorted and discarded in freezing conditions each year in Alaskan fisheries for Tanner crab (Chionoecetes bairdi) and snow crab (C. opilio). However,cold exposures vary widely over the fishing season and among different vessels, and mortalities are difficult to estimate. A shipb...
Main Author: | |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2009
|
Subjects: | |
Online Access: | http://hdl.handle.net/1834/25425 |
id |
ftoceandocs:oai:aquadocs.org:1834/25425 |
---|---|
record_format |
openpolar |
spelling |
ftoceandocs:oai:aquadocs.org:1834/25425 2023-05-15T18:20:07+02:00 Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index Stoner, Allan W. 2009 application/pdf 351-362 http://hdl.handle.net/1834/25425 en eng http://fishbull.noaa.gov/1074/stoner.pdf 0090-0656 http://hdl.handle.net/1834/25425 http://aquaticcommons.org/id/eprint/8776 403 2014-01-02 18:46:06 8776 United States National Marine Fisheries Service Biology Ecology Fisheries article TRUE 2009 ftoceandocs 2023-04-06T17:02:52Z Millions of crabs are sorted and discarded in freezing conditions each year in Alaskan fisheries for Tanner crab (Chionoecetes bairdi) and snow crab (C. opilio). However,cold exposures vary widely over the fishing season and among different vessels, and mortalities are difficult to estimate. A shipboard experiment was conducted to determine whether simple behavioral observations can be used to evaluate crab condition after low-temperature exposures.Crabs were systematically subjected to cold in seven different exposure treatments. They were then tested for righting behavior and six different ref lex actions and held to monitor mortality. Crabs lost limbs, showed ref lex impairment, and died in direct proportion to increases incold exposure. Righting behavior was a poor predictor of mortality, whereas reflex impairment (scored as the sumof reflex actions that were lost) was an excellent predictor. This composite index could be measured quickly and easily in hand, and logistic regression revealed that the relationship between reflex impairment and mortality correctly predicted 80.0% of the mortality and survival for C. bairdi, and 79.4% for C. opilio. These relationships provide substantial improvements over earlier approaches to mortality estimation and were independent of crab size and exposure temperature. Article in Journal/Newspaper Snow crab Chionoecetes bairdi Tanner crab IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications |
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 Stoner, Allan W. Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index |
topic_facet |
Biology Ecology Fisheries |
description |
Millions of crabs are sorted and discarded in freezing conditions each year in Alaskan fisheries for Tanner crab (Chionoecetes bairdi) and snow crab (C. opilio). However,cold exposures vary widely over the fishing season and among different vessels, and mortalities are difficult to estimate. A shipboard experiment was conducted to determine whether simple behavioral observations can be used to evaluate crab condition after low-temperature exposures.Crabs were systematically subjected to cold in seven different exposure treatments. They were then tested for righting behavior and six different ref lex actions and held to monitor mortality. Crabs lost limbs, showed ref lex impairment, and died in direct proportion to increases incold exposure. Righting behavior was a poor predictor of mortality, whereas reflex impairment (scored as the sumof reflex actions that were lost) was an excellent predictor. This composite index could be measured quickly and easily in hand, and logistic regression revealed that the relationship between reflex impairment and mortality correctly predicted 80.0% of the mortality and survival for C. bairdi, and 79.4% for C. opilio. These relationships provide substantial improvements over earlier approaches to mortality estimation and were independent of crab size and exposure temperature. |
format |
Article in Journal/Newspaper |
author |
Stoner, Allan W. |
author_facet |
Stoner, Allan W. |
author_sort |
Stoner, Allan W. |
title |
Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index |
title_short |
Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index |
title_full |
Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index |
title_fullStr |
Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index |
title_full_unstemmed |
Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index |
title_sort |
prediction of discard mortality for alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index |
publishDate |
2009 |
url |
http://hdl.handle.net/1834/25425 |
genre |
Snow crab Chionoecetes bairdi Tanner crab |
genre_facet |
Snow crab Chionoecetes bairdi Tanner crab |
op_source |
http://aquaticcommons.org/id/eprint/8776 403 2014-01-02 18:46:06 8776 United States National Marine Fisheries Service |
op_relation |
http://fishbull.noaa.gov/1074/stoner.pdf 0090-0656 http://hdl.handle.net/1834/25425 |
_version_ |
1766197589306245120 |