Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index

Stoner, Allan W. (2009) Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index. Fishery Bulletin, 107(4), pp. 351-362.

[img]
Preview
PDF (The document's language is English .) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (347Kb) | Preview
Official URL: http://fishbull.noaa.gov/1074/stoner.pdf

Abstract

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 in cold exposure. Righting behavior was a poor predictor of mortality, whereas reflex impairment (scored as the sum of 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.

Item Type: Article
Title: Prediction of discard mortality for Alaskan crabs after exposure to freezing temperatures, based on a reflex impairment index
Personal Creator/Author:
CreatorsEmail
Stoner, Allan W.
Refereed: Yes
Journal or Publication Title: Fishery Bulletin
Volume: 107
Number: 4
Page Range: pp. 351-362
Date: 2009
ISSN: 0090-0656
Issuing Agency: United States National Marine Fisheries Service
Subjects: Biology
Ecology
Fisheries
Item ID: 8776
Depositing User: Patti M. Marraro
Date Deposited: 10 Jun 2012 09:00
Last Modified: 02 Jan 2014 18:46
URI: http://aquaticcommons.org/id/eprint/8776

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...