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7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
1/17
AnnaOlafsdo+r
GeorgeRoseCentreforFisheries
EcosystemResearch,
MemorialUniversity
Preparedfor:
ArccFisheryAlliance
OceansNorthCanada
TheGreenlandhalibutfisheryinNAFOSubarea0from1996
to2011
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
2/17
GreenlandhalibutmostvaluableCanadiangroundfish
speciesinNWAtlanc
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
3/17
OutlineTotalAllowableCatch(TAC)hasdoubleinthelast
decadedespiteminimalbiologicalknowledgeonstock
Analysis:
catchlengthfrequencydatafishsizebygeartypeyield-per-lengthnumberofindividualfishforatoncaught
Recommendaons:morereserachneededslot-lengthapproachtoharvesngshouldbeconsidered,reducingfishingoflength80cm
SmallFishProtocol(
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
4/17
LimitedknowledgeonbiologyofGreenlandhalibutin0A
and0B
Background:biology
Age
Growthrate
Sizeatmaturity
Spawningstockbiomass
Fishingmortality
?Yield-per-recruit
Biologicalreferencepoints
Fishingsustainability
RiskassessmentoncurrentTACX
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
5/17
TACandcatchinSubarea0doubledbetween2000and2011
Background:fishery
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
6/17
Availablecatchlengthfrequencydatafromthefishery
Analysis:at-seaobserverdata
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
7/17
In0Atrawl:lengthoffishhasdeclinedsince2006
Analysis:lengthfrequency
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
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In0Btrawl:lengthoffishhasincreasedsince2006
Analysis:lengthfrequency
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
9/17
Gillnets:limitedchangesinfishlengthsincefisherybegan
Analysis:lengthfrequency
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
10/17
TrawlsoenviolateSmallFishProtocol(max15%
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
11/17
Gillnetscatchlargerfishthandotrawls
Analysis:fishlength
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
12/17
Sustainablefisheryis
balancingbirthanddeath
Yield-per-lengthmodels:
1)calculateyieldperindividual
assumingspecificfishing
mortality
2)esmateatwhatlength
fishingshouldstartfor
maximumyield
stockbiomass
growthreproducon
fishingmortality
naturalmortalityX
fisheriesscience
Yieldcanbeesmated
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
13/17
Gillnetsulizefishgrowthpotenalbeerbycatching
largerfish
Analysis:yield-per-length
F=fishingmortalityZ=totalmortality
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
14/17
Fishingmortalityaffectsyield-per-length
Analysis:yield-per-length
F=fishingmortality
Z=totalmortality
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
15/17
Trawlscatchtwiceasmanynumberoffishforatoncaught
thandogillnets
Analysis:numberperton
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
16/17
Annuallytrawlscatch3-4millionfishandgillnets1-1.5
millioninDivision0A
Analysis:numberperton
7/30/2019 PowerPoint Presentation by Anna Olafsdottir of Memoral University, St. John's Nfld.
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Summary:applyprecauonaryapproachunlmore
biologicalinformaononstockareavailable
All13years
Conclusions: 1)Researchneededtoestablishsustainabilityoffisheryand
biologicalreferencepoints
2)Smallversuslargefish?Immatureversusmaturefish?
Recommendaons:1)moreresearch
2)considerslot-lengthapproachtoharvesng,reducing
fishingoflenght80cm
3)enforcethesmallfishprotocol(