An assessment of discard mortality for two Alaskan crab species, Tanner crab ( Chionoecetes bairdi) and snow crab (C. opilio), based on reflex impairment
Stoner, A.W.; Rose, C.S.; Munk, J.E.; Hammond, C.F.; Davis, M.W. (2008). An assessment of discard mortality for two Alaskan crab species, Tanner crab ( Chionoecetes bairdi) and snow crab (C. opilio), based on reflex impairment. Fish. Bull. 106(4): 337-347
In: Fishery Bulletin. US Government Printing Office: Washington, D.C.. ISSN 0090-0656; e-ISSN 1937-4518, more
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| Keywords |
Chionoecetes bairdi Rathbun, 1924 [WoRMS]
Marine/Coastal |
| Authors | | Top |
- Stoner, A.W.
- Rose, C.S.
- Munk, J.E.
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- Hammond, C.F.
- Davis, M.W.
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| Abstract |
Delayed mortality associatedwith discarded crabs andfishes has ordinarily been observedthrough tag and recovery studies orduring prolonged holding in decktanks, and there is need for a moreeff icient assessment method. Chionoecetesbairdi (Tanner crab) andC. opilio (snow crab) collected withbottom trawls in Bering Sea watersoff Alaska were evaluated for reflexesand injuries and held onboard to trackmortality. Presence or absence of sixref lex actions was determined andcombined to calculate a reflex impairmentindex for each species. Logisticregression revealed that ref leximpairment provided an excellentpredictor of delayed mortality in C.Opilio (91% correct predictions). ForC. bairdi, ref lex impairment, alongwith injury score, resulted in 82.7%correct predictions of mortality, andref lex impairment alone resulted in79.5% correct predictions. The relationshipsbetween ref lex impairmentscore and mortality were independentof crab gender, size, and shellcondition, and predicted mortalityin crabs with no obvious externaldamage. These relationships providesubstantial improvement over earlierpredictors of mortality and will helpto increase the scope and replicationof fishing and handling experiments.The general approach of using ref lexactions to predict mortality should beequally valuable for a wide range ofcrustacean species. |
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