ArticlePDF AvailableLiterature Review

Updating the AIHTS Trapping Standards to Improve Animal Welfare and Capture Efficiency and Selectivity

Authors:
  • Alpha Wildlife Research and Management Ltd.
  • RGL Recovery Wildlife Health & Veterinary Services

Abstract and Figures

In 1999, after pressure from the European Union, an Agreement on International Humane Trapping Standards (AIHTS) that would result in the banning of the steel-jawed leghold traps in the European Community, Canada, and Russia was signed. The United States implemented these standards through an Agreed Minute with the European Community. Over the last two decades, scientists have criticized the AIHTS for (1) omitting species that are commonly trapped; (2) threshold levels of trap acceptance that are not representative of state-of-the-art trap technology; (3) excluding popular traps which are commonly used by trappers although they are known to cause prolonged pain and stress to captured animals; (4) inadequate coverage of capture efficiency and species selectivity (i.e., number of captures of target and non-target species) performance. Concerns about the ability of standards and test procedures to ensure animal welfare, and about the implementation of standards, have also been voiced by wildlife biologists, managers, and conservation groups. In this review, we present a synopsis of current trapping standards and test procedures, and we compare the standards to a then contemporary 1985-1993 Canadian trap research and development program. On the basis of the above-noted concerns about AIHTS, and our experience as wildlife professionals involved in the capture of mammals, we formulated the following hypotheses: (1) the list of mammal species included in the AIHTS is incomplete; (2) the AIHTS have relatively low animal welfare performance thresholds of killing trap acceptance and do not reflect state-of-the-art trapping technology; (3) the AIHTS animal welfare indicators and injuries for restraining traps are insufficient; (4) the AIHTS testing procedures are neither thorough nor transparent; (5) the AIHTS protocols for the use of certified traps are inadequate; (6) the AIHTS procedures for the handling and dispatching of animals are nonexistent; (7) the AIHTS criteria to assess trap capture efficiency and species selectivity are inappropriate. We conclude that the AIHTS do not reflect state-of-the-art trapping technology, and assessment protocols need to be updated to include trap components and sets, animal handling and dispatching, and trap visit intervals. The list of traps and species included in the standards should be updated. Finally, the concepts of capture efficiency and trap selectivity should be developed and included in the standards. Based on our review, it is clear that mammal trapping standards need to be revisited to implement state-of-the-art trapping technology and improve capture efficiency and species selectivity. We believe that a committee of international professionals consisting of wildlife biologists and veterinarians with extensive experience in the capture of mammals and animal welfare could produce new standards Animals 2020, 10, 1262 2 of 26 within 1-2 years. We propose a series of measures to fund trap testing and implement new standards. Abstract: In 1999, after pressure from the European Union, an Agreement on International Humane Trapping Standards (AIHTS) that would result in the banning of the steel-jawed leghold traps in the European Community, Canada, and Russia was signed. The United States implemented these standards through an Agreed Minute with the European Community. Over the last two decades, scientists have criticized the AIHTS for (1) omitting species that are commonly trapped; (2) threshold levels of trap acceptance that are not representative of state-of-the-art trap technology; (3) excluding popular traps which are commonly used by trappers although they are known to cause prolonged pain and stress to captured animals; (4) inadequate coverage of capture efficiency and species selectivity (i.e., number of captures of target and non-target species) performance. Concerns about the ability of standards and test procedures to ensure animal welfare, and about the implementation of standards, have also been voiced by wildlife biologists, managers, and conservation groups. In this review, we present a synopsis of current trapping standards and test procedures, and we compare the standards to a then contemporary 1985-1993 Canadian trap research and development program. On the basis of the above-noted concerns about AIHTS, and our experience as wildlife professionals involved in the capture of mammals, we formulated the following hypotheses: (1) the list of mammal species included in the AIHTS is incomplete; (2) the AIHTS have relatively low animal welfare performance thresholds of killing trap acceptance and do not reflect state-of-the-art trapping technology; (3) the AIHTS animal welfare indicators and injuries for restraining traps are insufficient; (4) the AIHTS testing procedures are neither thorough nor transparent; (5) the AIHTS protocols for the use of certified traps are inadequate; (6) the AIHTS procedures for the handling and dispatching of animals are nonexistent; (7) the AIHTS criteria to assess trap capture efficiency and species selectivity are inappropriate. We conclude that the AIHTS do not reflect state-of-the-art trapping technology, and assessment protocols need to be updated to include trap components and sets, animal handling and dispatching, and trap visit intervals. The list of traps and species included in the standards should be updated. Finally, the concepts of capture efficiency and trap selectivity should be developed and included in the standards. Based on our review, it is clear that mammal trapping standards need to be revisited to implement state-of-the-art trapping technology and improve capture efficiency and species selectivity. We believe that a committee of international professionals consisting of wildlife biologists and veterinarians with extensive experience in the capture of mammals and animal welfare could produce new standards within 1-2 years. We propose a series of measures to fund trap testing and implement new standards.
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Animals2020,10,1262;doi:10.3390/ani10081262www.mdpi.com/journal/animals
Review
UpdatingtheAIHTSTrappingStandardstoImprove
AnimalWelfareandCaptureEfficiency
andSelectivity
GilbertProulx
1,
*,MarcCattet
2
,ThomasL.Serfass
3
andSandraE.Baker
4
1
AlphaWildlifeResearch&ManagementLtd.,229LilacTerrace,SherwoodPark,ABT8H1W3,Canada
2
RGLRecoveryWildlifeHealth&VeterinaryServices,415MountAllisonCrescent,
Saskatoon,SKS7H4A6,Canada;rgloperations.mcattet@gmail.com
3
DepartmentofBiologyandNaturalResources,FrostburgStateUniversity,Frostburg,MD21532,USA;
TSerfass@frostburg.edu
4
WildlifeConservationResearchUnit,DepartmentofZoology,TheRecanatiKaplanCentre,
UniversityofOxford,TubneyHouse,AbingdonRoad,Tubney,AbingdonOX135QL,UK;
sandra.baker@zoo.ox.ac.uk
*Correspondence:gproulx@alphawildlife.ca
Received:2July2020;Accepted:23July2020;Published:24July2020
Summary:In1999,afterpressurefromtheEuropeanUnion,anAgreementonInternational
HumaneTrappingStandards(AIHTS)thatwouldresultinthebanningofthesteeljawedleghold
trapsintheEuropeanCommunity,Canada,andRussiawassigned.TheUnitedStatesimplemented
thesestandardsthroughanAgreedMinutewiththeEuropeanCommunity.Overthelasttwo
decades,scientistshavecriticizedtheAIHTSfor(1)omittingspeciesthatarecommonlytrapped;(2)
thresholdlevelsoftrapacceptancethatarenotrepresentativeofstateofthearttraptechnology;(3)
excludingpopulartrapswhicharecommonlyusedbytrappersalthoughtheyareknowntocause
prolongedpainandstresstocapturedanimals;(4)inadequatecoverageofcaptureefficiencyand
speciesselectivity(i.e.,numberofcapturesoftargetandnontargetspecies)performance.Concerns
abouttheabilityofstandardsandtestprocedurestoensureanimalwelfare,andaboutthe
implementationofstandards,havealsobeenvoicedbywildlifebiologists,managers,and
conservationgroups.Inthisreview,wepresentasynopsisofcurrenttrappingstandardsandtest
procedures,andwecomparethestandardstoathencontemporary1985–1993Canadiantrap
researchanddevelopmentprogram.OnthebasisoftheabovenotedconcernsaboutAIHTS,and
ourexperienceaswildlifeprofessionalsinvolvedinthecaptureofmammals,weformulatedthe
followinghypotheses:(1)thelistofmammalspeciesincludedintheAIHTSisincomplete;(2)the
AIHTShaverelativelylowanimalwelfareperformancethresholdsofkillingtrapacceptanceand
donotreflectstateofthearttrappingtechnology;(3)theAIHTSanimalwelfareindicatorsand
injuriesforrestrainingtrapsareinsufficient;(4)theAIHTStestingproceduresareneitherthorough
nortransparent;(5)theAIHTSprotocolsfortheuseofcertifiedtrapsareinadequate;(6)theAIHTS
proceduresforthehandlinganddispatchingofanimalsarenonexistent;(7)theAIHTScriteriato
assesstrapcaptureefficiencyandspeciesselectivityareinappropriate.WeconcludethattheAIHTS
donotreflectstateofthearttrappingtechnology,andassessmentprotocolsneedtobeupdatedto
includetrapcomponentsandsets,animalhandlinganddispatching,andtrapvisitintervals.The
listoftrapsandspeciesincludedinthestandardsshouldbeupdated.Finally,theconceptsof
captureefficiencyandtrapselectivityshouldbedevelopedandincludedinthestandards.Basedon
ourreview,itisclearthatmammaltrappingstandardsneedtoberevisitedtoimplementstateof
thearttrappingtechnologyandimprovecaptureefficiencyandspeciesselectivity.Webelievethat
acommitteeofinternationalprofessionalsconsistingofwildlifebiologistsandveterinarianswith
extensiveexperienceinthecaptureofmammalsandanimalwelfarecouldproducenewstandards
Animals2020,10,12622of26
within1–2years.Weproposeaseriesofmeasurestofundtraptestingandimplementnew
standards.
Abstract:In1999,afterpressurefromtheEuropeanUnion,anAgreementonInternationalHumane
TrappingStandards(AIHTS)thatwouldresultinthebanningofthesteeljawedlegholdtrapsin
theEuropeanCommunity,Canada,andRussiawassigned.TheUnitedStatesimplementedthese
standardsthroughanAgreedMinutewiththeEuropeanCommunity.Overthelasttwodecades,
scientistshavecriticizedtheAIHTSfor(1)omittingspeciesthatarecommonlytrapped;(2)
thresholdlevelsoftrapacceptancethatarenotrepresentativeofstateofthearttraptechnology;(3)
excludingpopulartrapswhicharecommonlyusedbytrappersalthoughtheyareknowntocause
prolongedpainandstresstocapturedanimals;(4)inadequatecoverageofcaptureefficiencyand
speciesselectivity(i.e.,numberofcapturesoftargetandnontargetspecies)performance.Concerns
abouttheabilityofstandardsandtestprocedurestoensureanimalwelfare,andaboutthe
implementationofstandards,havealsobeenvoicedbywildlifebiologists,managers,and
conservationgroups.Inthisreview,wepresentasynopsisofcurrenttrappingstandardsandtest
procedures,andwecomparethestandardstoathencontemporary1985–1993Canadiantrap
researchanddevelopmentprogram.OnthebasisoftheabovenotedconcernsaboutAIHTS,and
ourexperienceaswildlifeprofessionalsinvolvedinthecaptureofmammals,weformulatedthe
followinghypotheses:(1)thelistofmammalspeciesincludedintheAIHTSisincomplete;(2)the
AIHTShaverelativelylowanimalwelfareperformancethresholdsofkillingtrapacceptanceand
donotreflectstateofthearttrappingtechnology;(3)theAIHTSanimalwelfareindicatorsand
injuriesforrestrainingtrapsareinsufficient;(4)theAIHTStestingproceduresareneitherthorough
nortransparent;(5)theAIHTSprotocolsfortheuseofcertifiedtrapsareinadequate;(6)theAIHTS
proceduresforthehandlinganddispatchingofanimalsarenonexistent;(7)theAIHTScriteriato
assesstrapcaptureefficiencyandspeciesselectivityareinappropriate.WeconcludethattheAIHTS
donotreflectstateofthearttrappingtechnology,andassessmentprotocolsneedtobeupdatedto
includetrapcomponentsandsets,animalhandlinganddispatching,andtrapvisitintervals.The
listoftrapsandspeciesincludedinthestandardsshouldbeupdated.Finally,theconceptsof
captureefficiencyandtrapselectivityshouldbedevelopedandincludedinthestandards.Basedon
ourreview,itisclearthatmammaltrappingstandardsneedtoberevisitedtoimplementstateof
thearttrappingtechnologyandimprovecaptureefficiencyandspeciesselectivity.Webelievethat
acommitteeofinternationalprofessionalsconsistingofwildlifebiologistsandveterinarianswith
extensiveexperienceinthecaptureofmammalsandanimalwelfarecouldproducenewstandards
within1–2years.Weproposeaseriesofmeasurestofundtraptestingandimplementnew
standards.
Keywords:AIHTS;animalwelfare;captureefficiency;captureselectivity;humaneness;
internationaltrappingstandards;InternationalOrganizationforStandardization(ISO);mammals;
trapping;wildlifemanagement
1.Introduction
In1987,theInternationalOrganizationforStandardization(ISO),throughTechnicalCommittee
191,begantodevelophumanemammaltrappingstandards[1].Theobjectiveofthecommitteewas
torecommendscientificallymeasurablespeciesspecificanimalwelfare(humane)thresholdsthat
reflectedstateoftheart(i.e.,thelatestandmostsophisticatedoradvancedstageofatechnology)
trappingsystemsinternationally[2].
In1991,becausenointernationalhumanetrappingstandardswereyetavailable,theCouncilof
theEuropeanUnion(EU–politicalandeconomicunionformerlyestablishedin1993fromthe
incorporationoftheEuropeanCommunities;itencompasses27memberstates,buttheUnited
KingdomlefttheEuropeanUnioninJanuary2020)adoptedthe“LegholdTrap”Regulation3254/91.
Animals2020,10,12623of26
Thisregulationprohibited(a)theuseoflegholdtrapsintheEuropeancommunityand(b)the
introductionintotheEuropeancommunityofpeltsandmanufacturedgoodsfromcountriesthat
captureanimalsbyusinglegholdtrapsortrappingmethodsthatdonotmeetinternationalhumane
trappingstandards[3],which,atthetime,stillneededtobedevelopedandapproved.
In1995,underpressurefromtheEU,negotiationsbegantowardanAgreementonInternational
HumaneTrappingStandards(AIHTS)thatwouldresultinthebanningofsteeljawedlegholdtraps
intheterritoriesofsignatorycountries[2].ThisagreementwassignedbytheEuropeanCommunity,
Canada,andRussiain1997[3].TheUnitedStatesofAmericaimplementedhumanetrapping
standardsthroughanAgreedMinutewiththeEuropeanCommunity,whichvirtuallyreplicatedthe
AIHTStext[4,5].AccordingtotheAIHTSandtheAgreedMinute,restrainingandkillingtrapsused
forthecaptureofmembersofcertainmammalianspecies,tradedamongthepartiesfortheirfur,
shouldbecertifiedinaccordancewithasetofstandardscontainedintheAIHTS[3,4].
TheAIHTSisabindingagreementthathasadirectimpactonfurtradingbetweenthesignatory
parties[3].Inthesecountries,theAIHTSidentifiescertifiedtrapstoaddressanimalwelfareconcerns
associatedwithtrapping.AlthoughtheAIHTSadaptedsomeoftheISOtestingprocedures[6,7]to
developtheirownstandards,theISOstandardshavenolegalvaluesorenforcementcapabilities.The
useofISOstandardsisvoluntaryandhasnoimpactonthetradeofgoodsorthelegitimacyoftraps
usedtocapturemammals.
TheAIHTSstandardsarenowmorethan20yearsold.Overthistime,scientistshavecriticized
theseAIHTSfor(1)omittingspeciesthatarecommonlytrapped[8];(2)thresholdlevelsofacceptance
thatarenotrepresentativeofstateofthearttraptechnology[9,10];(3)excludingcommonlyused
trapswhichareknowntocauseprolongedpainandstresstocapturedanimals[11,12];(4)inadequate
guidelinestoassesscaptureefficiencyandspeciesselectivity(i.e.,numberofcapturesoftargetand
nontargetspecies)performance[13].Concernshavebeenvoicedbywildlifebiologists,managers,
andconservationgroupsabouttheineffectivenessofstandardsandtestproceduresinensuring
animalwelfare[14]andinimplementingstandards[12,15,16].Refinementoftheinternational
trappingstandardsisrequiredtoensurethattheygeneratedesirableoutcomesforanimalwelfare
anddonotprecludethedevelopmentofimprovedmethods[17].
Consideringthegrowingconcernsofthepublicandthescientificcommunityaboutthewelfare
ofwildlife[18–20],webelievethatthetimehascometoreviewtrappingstandards,whicharenow
outdatedfrombothascientific[9,10]andsocietal[21,22]pointofview.Onthebasisoftheabove
notedconcernsaboutAIHTS,andourexperienceaswildlifeprofessionalsinvolvedinthecaptureof
mammals,weformulatedthefollowinghypotheses:(1)thelistofmammalspeciesincludedinthe
AIHTSisincomplete;(2)theAIHTShaverelativelylowanimalwelfareperformancethresholdsof
killingtrapacceptanceanddonotreflectstateofthearttrappingtechnology;(3)theAIHTSanimal
welfareindicatorsandinjuriesforrestrainingtrapsareinsufficient;(4)theAIHTStestingprocedures
areneitherthoroughnortransparent;(5)theAIHTSprotocolsfortheuseofcertifiedtrapsare
inadequate;(6)theAIHTSproceduresforthehandlinganddispatchingofanimalsarenonexistent;
(7)theAIHTScriteriatoassesstrapcaptureefficiencyandspeciesselectivityareinappropriate.
2.ASynopsisofTrappingStandards
WesummarizedtheISOstandards[6,7]andtheAIHTS[3]inTable1inordertoprovidethe
contextforoursubsequentreviewofissuesandconcerns.Inordertounderstandourdiscussionof
traptestingprotocolsincludedinstandards,webrieflydescribetestingproceduresbelow[10].
WhereastheAIHTSreferto“humane”standards,webelievethistermtobeinappropriate
because,aswildlifeprofessionals,weshouldbeconstantlystrivingforimprovement[8,10,17,23].
Althoughfrequentlyusedinthescientificliterature,thistermmayimplythathumanenessisbinary
[24]andthat,onceatraphasbeencertifiedas“humane”,thereisnoneedforfurtherimprovement.
Inthispaper,unlessthetermhasbeencitedinreferredstandards,wereplace“humanestandards”
with“standards”.
Animals2020,10,12624of26
Table1.ComparisonofInternationalOrganizationforStandardization(ISO)andAgreementonInternationalHumaneTrappingStandards(AIHTS)(excerptsfrom
theoriginaldocuments)toaCanadianresearchprotocolconductedinparallelwiththedevelopmentofthestandards.
Subject
Standards1985–1993CanadianResearchProgram[10]
ISO[6,7]AIHTS[3]
RestrainingTrapsKillingTrapsRestrainingTrapsKillingTrapsRestrainingTrapsKillingTraps
LegalsignificanceNone
Bindingagreementeachpartyshouldtakethenecessary
stepstoensurethattherespectivecompetentauthorities
(a)establishappropriateprocessesforcertifyingtrapsin
accordancewiththestandards;(b)ensurethatthe
trappingmethodsconductedintheirrespectiveterritories
areinaccordancewiththestandards;(c)prohibittheuse
oftrapsthatarenotcertifiedinaccordancewiththe
standards;(d)requiremanufacturerstoidentifycertified
trapsandprovideinstructionsfortheirappropriate
setting,safeoperation,andmaintenance.
None
Definition
Deviceusedtocaptureand
restrainamammal.A
restrainingtrapsystem
encompassesequipment(trap
andtrigger)andset(site
modifications,lures,and
baits).
Deviceforuseonlandor
underwatertokilla
mammal.Akillingtrap
systemencompasses
equipment(trapand
trigger)andset(site
modifications,lures,and
baits).
Trapsdesignedandsetwiththe
intentionofnotkillingthe
trappedanimalbutrestricting
itsmovementstosuchanextent
thatahumancanmakedirect
contactwithit.
Trapsdesignedandset
withtheintentionof
killingatrapped
animalofthetarget
species.
AsperISOandAIHTS
ListofspeciesAllmammalspecies
Coyote(Canislatrans)
Wolf(Canislupus)
NorthAmericanbeaver(Castorcanadensis)
Europeanbeaver(Castorfiber)
Bobcat(Felisrufus)
NorthAmericanotter(Lontracanadensis)
Europeanotter(Lutralutra)
Canadalynx(Lynxcanadensis)
Europeanlynx(Lynxlynx)
Americanmarten(Martesamericana)
Fisher(Pekaniapennanti)
Sable(Marteszibellina)
Pinemarten(Martesmartes)
Europeanbadger(Melesmeles)
Ermine(Mustelaerminea)
Raccoondog(Nyctereutesprocyonoides)
Muskrat(Ondatrazibethicus)
Allmammalspecies
Speciesforwhichacceptabletrapshavebeen
developedbyresearchersaccordingto
performancelevelspresentedbelow:
Arcticfox(Vulpeslagopus)
Redsquirrel(Tamiasciurushudsonicus)
Northernpocketgopher(Thomomystalpoides)
Canadalynx
Americanmarten
Fisher
Americanmink(Neovisonvison)
Raccoon
Animals2020,10,12625of26
Raccoon(Procyonlotor)
NorthAmericanbadger(Taxideataxus)
TestingprocedureFieldtesting
Pathologicalevaluation
Mechanicalevaluation
Killtestswith
anaesthetizedanimals.
Killtestsincompounds.
Fieldtests.
Pathologicalevaluations.
Inspectionandtestingfor
usersafetyandtraps.
Compoundteststoevaluate
behavioural,physiological,and
biochemicalparameters.
Fieldtests(vs.acontroltrap)to
assessselectivityanduser
safety.
Pathologicalevaluations.
Approachteststo
ensureaproper
positioningofthe
animalsinthetraps.
Killtestsincompounds
toassesslossof
consciousness.
Fieldtests(vs.acontrol
trap)toassess
selectivityanduser
safety.
Pathological
evaluations.
Mechanicalevaluation
tocompareimpact
momentumand
clampingforcesof
differenttrapmodels.
Compoundteststo
assessbehaviouraland
physiological
parameters.
Fieldtests(vs.acontrol
trap)toassess
selectivityanduser
safety.
Pathological
evaluations.
Mechanical
evaluationto
assessthe
potentialoftraps.
Approachteststo
ensureaproper
positioningofthe
animalsinthe
traps.
Killtestswith
anaesthetized
animalstoassess
lossof
consciousnessin
nonreactive
animals.
Killtestsin
compoundsto
assesslossof
consciousnessin
conscious
animals.
Fieldteststo
verifycompound
testfindings.
Pathological
evaluationsin
compoundand
fieldtests.
Inspectionand
testingforuser
safetyandtraps.
Testreport
Humaneness:reportonthe
positionofeachanimalinthe
trapandevaluationofthe
conditionofthecaptured
animalsaccordingtoa
traumascale,withscores
proportionaltotheseverityof
theinjuries.
Humaneness:reporton
strikelocationandtimeto
lossofcornealand
palpebralreflexesand
heartbeat.
Fieldtests:numberof
capturesoftargetand
nontargetspecies.
Humaneness
Behaviouralindicatorsofpoor
welfare:
Selfmutilation
Excessiveimmobilityand
unresponsiveness.
Humaneness
Thetimeofoccurrence
andinsensibility
producedbythekilling
techniquebasedonthe
lossofcornealand
palpebralreflexesor
anyotherspecifically
Humaneness:reporton
thepositionofeach
animalinthetrapand
evaluationofthe
conditionofthe
capturedanimals
accordingtoatrauma
scalewithscores
proportionaltothe
Humaneness
Thenumberof
animalstested
andthe
proportionthat
lostinsensibility
basedontheloss
ofcornealand
palpebralreflexes.
Animals2020,10,12626of26
Fieldtests:numberof
capturesoftargetandnon
targetspecies.
Usersafety:fieldnotes.
Compoundandfieldtests:
pathologicalobservations.
Usersafety:fieldnotes.
Physicalindicatorsofpoor
welfareaccordingtooccurrence
ofseriousandsevereinjuries.
provensuitable
substituteparameter:
45sec—Mustelaerminea
120sec—Martesspp.
300sec—allother
specieslistedabove.
severityoftheinjuries;
totalinjuriesmust
amountto<50points
onthescale.
Fieldtests:Numberof
capturesoftargetand
nontargetspecies.
Usersafety:fieldnotes.
3min—allspecies
exceptlarge
carnivores.
5min—Redfox
(VulpesVulpes)
Numberoftests
Unspecified.Thenumberof
replicatesinthetestsshallbe
sufficienttodetermineifthe
differencesarestatistically
significantattheleveltobe
determinedbytheauthority
implementingthetest.
Comparisonofselectivity
(numberofcapturedtarget
animalsdividedbythetotal
numberofcapturedanimals)
withacontroltrapanduser
safetyasspecifiedbythe
authorityimplementingthe
standard.
Unspecified.Capabilityof
akillingtrap,aspartof
thekillingtrapsystem,
tokillananimalwithina
timeperiodandtomeet
therequirementsrelated
tomechanicalproperties,
comparisonofselectivity
(numberofcaptured
targetanimalsdividedby
thetotalnumberof
capturedanimals)witha
controltrapmodel,and
usersafetyasspecifiedby
theauthority
implementingthe
standard.
Thenumberofspecimensofthe
sametargetspeciesfromwhich
thedataarederivedisatleast
20.
Thenumberof
specimensofthesame
targetspeciesfrom
whichthedataare
derivedisatleast12.
9specimensfor
compoundtests.
>30specimensforfield
testswherecapture
durations
24h.
6specimensfor
approachtests
9specimensfor
compoundkill
tests.
>30specimensfor
fieldtests.
Minimum
successful
compoundtests
requiredtomeet
performance
thresholds
NoneNone
Atleast16(80%)of20animals
shownoneoftheindicators
listedabove.
Atleast10(80%)of12
animalsare
unconsciousand
insensiblewithinthe
timelimitandremain
inthisstateuntildeath.
9/9(100%),or13/14(93%),or21/24(88%),etc.
(proportionsbasedonthenormal
approximationtothebinomialdistribution).
Predicted
performance
thresholdat
populationlevel
(95%confidence
level)resulting
fromthenumber
ofsuccessful
testsonetailed
binomialtest
n/an/a57%49%71%
Animals2020,10,12627of26
2.1.TestProcedures
Mechanicalevaluations:restrainingandkillingtrapsaretestedinalaboratorytodetermine
impactmomentumandclampingforces.Impactmomentumistheproductofthevelocityofa
strikingbarmultipliedbyitsequivalentmass.Theclampingforceisthesteadystateforceexertedon
ananimalbythejawsofthetrapafterthestrikingforcehasbeendelivered.Mechanicalevaluations
oftrapsareimportantbecausetheyidentifythemaximumenergylevelsthatmaycauseserious
injuriesinanimalscapturedinrestrainingtraps(e.g.,footholdtraps)orenergylevelsassociatedwith
timetoirreversibleunconsciousness(TIU)foranimalsstruckinvitalregionsbykillingtraps[10,25].
Trapclampingforceandimpactmomentumarewidelyacceptedproxiesoftrapwelfareperformance
amongspringtraps[6,10,25].Paststudieswithkillingtrapsshowedthatimpactmomentumand
clampingforcethresholdsvarybetweenstrikelocationswithinspeciesandthatneitherforceis
directlyrelatedtotargetspeciesbodyweight[26–28].Mechanicalforcescannotthereforebeusedto
predictTIUbetweenspeciesbasedontheirbodyweight.However,dataonimpactmomentumand
clampingforceproducedbyatrapandtheTIUforacertainspecieskilledinthattrapmaybeused
inthescreeningofothertrapsforthesamespecies,providedthatthestrikelocationisthesamefor
bothtypesoftraps[25,26].Mechanicalevaluationsallowonetoperformqualitycontrolcheckson
mechanicaltraps[26]andassesshowmodificationsoftrapdesignsoptimizethepotentialofatrap
torestrainorkillananimal.
Compoundtestswithrestrainingtraps:freeranginganimalsinfencedcompounds(semi
naturalenvironments)arecapturedandkeptintrapsfor≤24handaremonitoredforinjuriesand
behaviouralchanges.Capturedanimalswithsevereinjuries(e.g.,fractureofbonesorteeth,joint
luxation,severanceoftendonsorligaments,internalhaemorrhages,corneallaceration,amputation,
etc.)andsignsofpainandsufferingareeuthanizedimmediately.Animalswithoutapparentsevere
injuriesarekeptcaptiveforthedurationofthetests,euthanized,andnecropsied.Anassessmentof
thetrapmaybebasedonacumulativescoringsystem,wherepointsareassignedtothecaptured
limbandbodyaccordingtotheseverityofinjuries[29].
Approachtests:testsconductedincompoundswheretheanimalsareallowedtoapproachtraps
wiredinthesetpositionsothatthetrapscanbetriggeredbutcannotclosecompletelyandinjurethe
animals[30].Approachtestsareusedtoassesstheabilityoftrapstostrikeanimalsinvitalregions,
e.g.,theheadandneckregions[31].Trapsthatfailtheapproachtestsshouldnotbeallowedtobe
testedfurtheruntiltheyhavebeenmodifiedtostrikeanimalsproperly.
Killtestswithanaesthetizedanimals:testsassessingthepotentialoftrapstorender
anaesthetizedanimalsirreversiblyunconsciouswithinapredeterminedtimeperiod.Themusclesof
anaesthetizedanimalsaremorerelaxedthanthoseofnonanaesthetizedanimalsandofferless
resistancetothestrikingbarsthanconsciousanimalsthatarefightingthetrap[30,32].Trapsthat
successfullypasskilltestswithanaesthetizedanimalsmayormaynotpasskillingtestsin
compounds.However,theprobabilityoftrapsthatfailedkilltestswithanaesthetizedanimals
passingkillingtestsincompoundsisnull[30].Thiswasfurtherconfirmedthroughastatistical
comparisonofTIUsinkilltestswithandwithoutanaesthetizedanimals[33].Thus,trapsthatfailkill
testswithanaesthetizedanimalsarenotallowedtobefurthertestedbecausetheycouldnotrender
nonanaesthetizedanimalsunconsciousquickly.
Killtestsincompounds:teststoassessthepotentialoftrapstorendermobileanimals
irreversiblyunconsciouswithinapredeterminedtimeperiod.Alltestsarerecordedwithvideo
camerasandaremonitoredfromafar.Uponfiringofthetrap,researchersruntothecompoundto
monitorthestateofconsciousness(usingthecornealandpalpebralreflexes)ofthetrappedanimals
[30].AnimalsarenecropsiedtodeterminepathologicalmodificationsassociatedwithspecificTIUs
andtrapstrikelocations[34].
Fieldtests(restrainingandkillingtraps):testtrapsareevaluated,eitheralone(comparing
captureefficiencytodatareportedforothertraps)orinacomparisonwithcommonlyusedtraps[35],
toascertaincompoundtestfindings.Oneobjectiveoffieldtestsistocomparecaptureefficiencyand
speciesselectivitybetweenexperimentalandcommonlyusedtraps.Itisnoteworthytomentionthat
Animals2020,10,12628of26
trapswhicharecommonlyusedbytrappersmaynotmeetanimalwelfarestandards[36].Animals
arenecropsiedtocomparetrapstrikelocationsandpathologicalmodificationswiththoseofanimals
killedincompoundtests[36].
2.2.Comparisons
SincesomeoftheISOtestprocedureswereadaptedforthedevelopmentoftheAIHTS(Table
1),therearesimilaritiesbetweenthesestandards(Table1).TheAIHTSareanimprovementuponthe
ISOstandardsbecausetheyspecifyaminimumnumberofspecimensandtestsincompoundsanda
minimumnumberofsuccessfulteststoacceptatrapfromananimalwelfareperspective(Table1).
However,theAIHTSfailtospecifyaminimumofsuccessfuloutcomesinapproachteststoensure
thattrapshavethepotentialofstrikinganimalsinvitalregions.AlthoughtheAIHTSdonotinclude
eithermechanicalevaluationsorkilltestswithanaesthetizedanimalstoeliminatekillingtrapswith
lowkillingpotential,thestandardsindicatethatISOproceduresshouldbeusedasappropriate.
However,aswepreviouslyindicated,theISOstandardshavenolegalvalues.
InordertoassesswhethertheAIHTSreflectstateofthearttrappingtechnology,wecompared
thesestandardstothetestingproceduresandtrapacceptancecriteriaofaCanadiantrapresearch
anddevelopmentprogramthatwasconductedinparallelwiththedevelopmentoftheISOand
AIHTSstandards,from1985to1993(Table1).TheISOcommitteemembers,manyofwhomwere
subsequentlyinvolvedinthedevelopmentoftheAIHTS,werefamiliarwiththethencontemporary
Canadianresearchprogramanditsachievements[37].
3.Hypothesis1:TheListofMammalSpeciesIncludedintheAIHTSIsIncomplete
SincetheAIHTSwasdevelopedinresponsetocrueltyassociatedwiththeuseofsteeljawed
legholdtrapsinfurtrapping[2],standardswereunderstandinglydevelopedforfurbearerscaptured
forthepeltmarket[3].TheAIHTSidentified19furbearerspecies,ranginginsizefromstoat(Mustela
erminea)togreywolf(Canislupus)(Table1).However,thestandardsareaboutanimal(mammal)
trapsand,therefore,thelistofspeciescoveredbytheAIHTSisincompleteanddoesnotencompass
themajorityofspeciesbeingtrappedinCanada,USA,Russia,ortheEUaseitherfurbearers,pests,
researchanimals,orforconservationpurposes.
3.1.Furbearers
ManymorespeciesharvestedfortheirfurshouldbeaddedtotheAIHTS’list.Amongmustelids,
Americanmink(Neovisonvison),whicharecurrentlyexcludedfromthelist,areamongthemost
numerousandvaluablefurbearerscapturedinNorthAmerica[38,39].Thefactthatmostminkand
foxpeltscomefromcaptivefurstock[16]doesnotjustifyomittingthesespeciesfromtheAIHTSlist.
Additionally,althoughthousandsofleast(Mustelanivalis)andlongtailed(Mustelafrenata)weasels,
wolverines(Gulogulo),stripedskunks(Mephitismephitis),redfoxes(Vulpesvulpes),Arcticfoxes
(Vulpeslagopus),redsquirrels(Tamiasciurushudsonicus),Eurasianredsquirrels(Sciurusvulgaris),and
coypus(Myocastorcoypus)arelegallytrappedeveryyearinCanada,theUSA,andScandinavian
countries[38–40],theyarelikewiseoverlookedbytheAIHTS[3]forunknownreasons.
Sincetheimpactmomentumandclampingforcenecessarytocauseirreversibleconsciousness
withinacertaintimeframevaryamongspeciesandbetweenstrikelocationswithinspecies[26,27,41],
onecannotclaimthattrapsdevelopedforfurbearersofsimilarsizemaybeusedforspeciesnotlisted
intheAIHTS.Forexample,trapsdevelopedforAmericanmartens(Martesamericana)cannotbe
assumedacceptablefortrappingAmericanmink,whichhaveagreatercervicalmusculatureand
strongerbonesthanmartens[42].Trapsdevelopedforsmallandmediumsizedmammalscannotbe
usedfortherelativelysmallerweasels,becausetheymaystrikeanimalsinnonlethallocationsand
causedistressandpainfuldeaths[43].Additionally,atrapthatmaybesuitablefortrappingfishers
(Pekaniapennanti)[44]cannotbepresumedtobeadequateforthelargerandstrongerwolverine,as
strikelocationswilldifferbetweenspeciesofdifferentsizeandbehaviour.
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Manykillingtrapshavebeendevelopedandmanufacturedforfurbearersthatarenotincluded
intheAIHTS.Thesetrapsweredevelopedanddemonstratedtomeetmorestringenttimethresholds
toirreversibleunconsciousnessthantheAIHTS[42,45–49].Testsincompoundsandonworking
traplineshaveshownthattheC120Magnumwithpantriggercouldrenderminkirreversibly
unconsciousin<3min[42,45],andtheSauvageau20018rotatingjawtrapcouldrenderArcticfox
irreversiblyunconsciousin<3min[46,48].Finally,testsincompounds[47]andinthefield[49]have
shownthattheKaniatrapcouldrenderAmericanredsquirrelsirreversiblyunconsciousin<2min
andwasavaluablealternativetoineffectivetrapsandsnares.Allthesefurbearersshouldbepartof
theAIHTSlistofspecies.
3.2.Rodents
Manymillionsofbrownrats(Rattusnorvegicus)andhousemice(Musmusculus)inurbanareas
[50],andthousandsoffossorialrodentsinagriculturalfields[51,52],aretrappedgloballyeveryyear.
WebelievethatthesespeciesshouldbelistedintheAIHTS,although,ofcourse,theyarenot
furbearersandsoarecurrentlyexcluded.
3.3.OtherNonFurbearingSpecies
OthermammalsnotontheAIHTSfurbearerslistarealsotrappedinhighnumbers.Forexample,
althoughtrapsforrabbits,greysquirrels(Sciuruscarolinensis),thenonnativeAmericanmink,and
mostothermammalstrappedintheUKareregulatedtoAIHTSstandards,theyarenotincludedin
theAIHTS.Moreover,inCanada,newtrappingdevicesforspeciesnotincludedintheAIHTShave
beenindependentlydeveloped,tested,andrecognizedtoexceedAIHTSwelfarestandards,suchas
thePGTrapforthenorthernpocketgopher(Thomomystalpoides)[53].WesupportTallingandInglis’
[8]assertionthatallmammaltrapsshouldbesubjecttoregulationand,asdiscussedabove,with
appropriateTIUthresholds.
3.4.AnimalsUsedinResearchandConservationPrograms
Millionsofmammalsarealsobeingtrappedyearlybyresearchersforvariousconservation,
demographic,physiological,andbehaviouralstudies[54,55].Althoughsuchstudiesmaybesubject
toresearchandpublicationguidelinesandAnimalCareandUseCommittees[19,56,57],dataontraps
beingusedtosamplepopulationshavenotnecessarilybeeninvestigatedfromananimalwelfareand
selectivitypointofview.
Ungulatesarealsotrappedforresearch,relocation,orpopulationcontrol,butassessmentof
thesetraps[58,59]andtrappingstandardsarelackingintheAIHTS.
4.Hypothesis2:TheAIHTSHaveRelativelyLowAnimalWelfarePerformanceThresholdsof
AcceptanceofTrapsandDoNotReflectStateoftheArtTrappingTechnology
4.1.ThresholdsofAcceptance
Inordertobeacceptable,restrainingandkillingtrapsmustmeetthehighestpossibleanimal
welfarestandards,andtrapstandardsshouldberaisedasdevelopmentsintrappingtechnology
allow.Trapsmustbesubjectedtothoroughassessmentprogramswithappropriateacceptance
thresholdlevels.Ifsuchlevelsaresolowthatanytrapavailableonthemarketcanbecertified,trap
manufacturerswillnotbeencouragedtoimprovetrapwelfarestandards,andconcernsaboutanimal
welfareintrappingwillbeperpetuated.
Inthefollowing,weusedthe1985–1993Canadianresearchanddevelopmentprogramfor
comparisonpurposesbecausethisprogramproducedasignificantnumberofrestrainingandkilling
trapsforusewithAmericanmartens,Americanmink,fishers,northernraccoons(Procyonlotor),
Arcticfoxes,Canadalynx(Lynxcanadensis),andredsquirrels[60]thatwerethen,andstillaretoday,
representativeofstateofthearttechnology.TheCanadianresearchprogramimplementedstringent
acceptationcriteria[10]indicatingthatrestrainingtrapsshould,with95%confidence,hold≥70%of
Animals2020,10,126210of26
animalsfor≤24h,with≤50pointsscoredforphysicalinjury,i.e.,withoutseriousorsevereinjuries
[9,29,60];killingtrapsshould,with95%confidence,render≥70%ofcapturedanimalsirreversibly
unconsciousin≤3min[10,60,61](Table1).
InaccordancewithRusselandBursch’s“3Rs”principle(replacement,reduction,refinement)
[62],theCanadianresearchersaimedtominimizethenumberofanimalsusedintestingby
employingthenormalapproximationtothebinomialdistribution(onetailedtesting)toestimatethe
realpotentialoftraps[34].Incompoundtests,whenatrapkillsnineoutofnineanimalsaccording
tospecificcriteria,thesuccessrateis100%.However,intherealworld,withapopulationofhundreds
orthousandsofanimals,itisinconceivabletosuggestthatthetestedtrapmodelwouldsuccessfully
kill100%oftheanimalsaccordingtothespecifiedcriteria.Withthenormalapproximationtothe
binomialdistribution,however,researcherscouldpredicttheexpectedperformanceofthetested
trapsinalargepopulationofcapturedanimals.Canadianresearchersusedthefollowingequation:
P(X)=!
!!
𝑝𝑞(1)
wherenisthenumberofindependenttests.Eachtestmayresultinoneoftwooutcomes,“success”
or“failure”,withtheprobabilitiespandq,respectively.Inacompoundkillingexperimentwithone
trapmodelandnineanimals,ifninetestsaresuccessful(i.e.,nineanimalslostconsciousnesswithin
theprescribedtimelimit),andthereforefailureiszero,theprobabilityofthetrapbeingsuccessfulin
alargepopulationofanimalsisestimatedat71%(onetailedtest)[63–65].Thesameconclusionis
reachedwith13successesoutof14tests(i.e.,onefailure),18outof20(twofailures),or21outof24
(threefailures),etc.(Table1).Thus,ifatrapmodelsuccessfullykillsnineoutofnineanimalsin
compoundtests,itcanbeexpected,ata95%confidencelevel,tokill≥70%animalsofatargetspecies
capturedontraplines[34,45](Table1).IntheCanadianresearchprogram,trapsthatmetthis
acceptancecriterionwereallowedtoproceedtofieldtests.Fieldtestsontraplinesresultedinalarge
numberoftargetspeciescaptures,andstrikelocationsandpathologicalevidencewereusedto
confirmconclusionsdrawnfromcompoundkilltestthresholdlevels.Forexample,killingtrapsfor
Americanmartens,Americanmink,andArcticfoxesthathadmettheacceptancethresholdlevelsin
compoundtestssuccessfullykilled99%,97%,and100%oftheanimalsofeachspecies,respectively,
ontraplines[36,45,46].
AccordingtotheAIHTS,successfulrestrainingtrapsmustcaptureatleast16/20animalswithout
seriousinjuries,thussuggestingthattrapswillbehumaneinatleast80%ofcaptures[3].However,
onthebasisofthenormalapproximationtothebinomialdistribution,therealpotentialofthese
AIHTScertifiedtrapsontraplinesisonly57%.Likewise,accordingtotheAIHTS,successfulkilling
trapsmustrenderunconscious10/12animalswithinapredeterminedtimeperiod,thussuggesting
thattrapswillbehumanein80%ofcaptures[3].However,therealpotentialofthetrapswouldonly
be49%,i.e.,theymayfailinnearly50%ofcaptures.Inthe1980s,theperformancethresholdusedby
theCanadianresearchteamwasconsideredtobethe“goldstandard”[60].TheAIHTSthresholdsof
acceptancearemarkedlylowerthanthis35yearold“goldstandard”,and,therefore,theAIHTSdo
notreflectstateofthearttrappingtechnology.Whileamendmentstotheagreementmaybe
proposedbytheAIHTSCommittee,oranysignatorycountry,atanytime[3],performancethresholds
havenotbeenupdatedsincethesigningoftheagreementin1997.
Whileaminimumperformanceof70%issuperiortotheactualperformanceachievedbythe
AIHTSstandards,westillbelievethatthisthresholdperformancelevelisinadequate.Forexample,
withaminimumperformancelevelof70%,30,000outof100,000capturedanimalscouldsufferlong
andpainfuldeathsorexperiencerestrainingconditionsthatareunacceptableinreallifetrapping
situations.WiththecurrentAIHTS,however,thesituationisevenworse,i.e.,51,000outof100,000
capturedanimalscouldsufferlongandpainfuldeathsinkillingtraps,and43,000restrainedanimals
maysufferunacceptablewelfareconditionsinrestrainingtraps.Comparedtothestandardsusedby
Canadianresearchers[10],21,000and13,000(21%and13%)moreanimals,respectively,wouldbe
subjectedtopoorwelfareconditionswhenbeingkilledorrestrainedaccordingtotheAIHTS.
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4.2.TimesofIrreversibleLossofConsciousness(TIUs)
AccordingtotheAIHTS,theuseofcertifiedtrapsshouldresultinTIUsof45sinstoatand
similarsmallspecies,120sinmartens(Martesspp.),and300sinotherfurbearerspecies.However,
Canadianresearchers[10,60]developedtrapsforAmericanredsquirrelswithaTIUof25sonly[47],
andof78and81sforlargerspecies[44,66].Withnewtechnologyandmaterialsdevelopedinthelast
fewdecades,TIUscouldpotentiallybereducedtolessthan60sformanyspecies.
Severalratandmousetraps(e.g.,someFenn,BMIMagnum,DOCtraps,Nooski,andGood
natureA24traps)areregulatedintheUK[67].However,thesetrapsareonlyexpectedtomeeta
thresholdforTIUsof300s,althoughmuchshorterTIUscanbeachievedwithsmallanimals.For
example,breakbacktrapsforratsandmicearespecificallyexemptfromregulationintheUKand,
asfarasweunderstand,generallyunregulatedglobally[68].Voluntarytrapapprovalstandardsused
forratsandmiceinGermany,suchasthoseoftheGermanEnvironmentAgencyandtheBlueAngel
(BlauerEngel)ecolabel,havethefollowingcategories:categoryAif80%oftestanimalslose
consciousnessin30sand90%in60s;categoryBif80%oftestanimalsareunconsciousin60sand
90%in180s[69].TheGorillamousetraphasbeencertifiedaccordingtothisstandard[70].
Clearly,muchlowerTIUsareachievable,atleastforsomesmallerspecies,thanthosesetoutin
theAIHTS,andwebelievethatapprovalthresholdsshouldbeoverhauledaccordingly.Inthe
widespreadabsenceofregulationforbreakbacktraps,manytrappingdevicesareusedbythepublic
withoutanyinformationontheabilityoftrapstostrikeanimalsinsuitablelocationsorquicklyrender
themunconscious[20].Bakeretal.[20]investigatedthepotentialwelfareperformanceofawide
selectionofunregulatedbreakbacktrapsforratsandmiceavailableintheUKbymeasuringtheir
mechanicalperformance.Theydemonstratedwidevariationinmechanicalperformanceamongtraps
foreachofthespecies,whichimplieswidevariationinwelfareperformance.Bakerandcoauthors
subsequentlyproposedavoluntarytrapapprovalschemeforunregulatedbreakbacktrapsinthe
UK[71,72].
Anactualperformancelevel>80%maynotbeunrealisticsincethishasbeenachievedin
previoustrapdevelopmentprograms[60,73].TrapsandlowerTIUsthatresultedfromtheCanadian
researchprogramdemonstratethattheAIHTSarenotrepresentativeofcurrentstateoftheart
technology.
SincetheAIHTSthresholdsdonotrepresentstateofthearttechnology,sometrapshavebeen
acceptedasbestmanagementpracticesbytheUSA.ThisisdespiteCanadianscientificevaluations
demonstratingthatthesetrapsdidnothavethepotentialtorender≥70%ofanimalsunconscious
within3min(thereforenotmeetingtheAIHTSthresholdlevelofperformance),andtheywould
causeunduepainandsufferingasaresult[15].ExamplesofsuchtrapsincludethepopularConibear
120rotatingjawtraps(seeAppendix5.1of[10]foradescriptionofdifferenttraptypes)forAmerican
martens[74]andAmericanmink[75],andtheConibear220rotatingjawtrapfornorthernraccoons
[76],allofwhichhavebeenfoundtocauselengthyperiodsofconsciousnessanddistressinprevious
assessments[30,32,42].
4.3.TrapExemptions
TheAIHTSspecifythatthepartiesoftheagreementmayderogatefromtheagreedstandards
fortheuseofsometraps,i.e.,theymayallowtheuseofnoncertifiedtrapsiftheirdecisiondoesnot
underminetheobjectivesoftheagreement,foranyofthefollowingpurposes:(a)theinterestsof
publichealthandsafety;(b)protectionofpublicandprivateproperty;(c)research,education,
repopulation,reintroduction,breeding,orfortheprotectionoffaunaandflora;(d)usingtraditional
woodentrapsessentialforpreservingculturalheritageofindigenouscommunities.InCanadaand
theUnitedStates,noncertifiedtrappingdevicesarecurrentlybeingusedinthefield(G.Proulx,
personalobservations),althoughtheiruselikelyunderminestheobjectivesoftheagreement.In
Canada,killingnecksnaresareanexampleoftrapexemptions.
AlthoughISO[6,7]testingprocedureswereincludedintheAIHTS[3],theISOdraftstandard
forkillingnecksnares[77]wasexcludedfromtheAIHTSbecausethesetrappingdevicesare
consideredtobehomemade(Article7oftheAIHTSexcludingtrapsmadebyindividuals)[12].
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However,manykillingnecksnaresaremanufacturedcommerciallyandsoldontheopenmarket[2],
andtheyshouldthereforebeconsideredcommercialdevicesandincludedintheAIHTS.Killingneck
snaresareunabletoquicklyrendercanidsunconscious[11,12];indeed,theanimalsmaystruggle
violentlyforhoursbeforelosingconsciousness[2].However,morethan100,000redfoxes,coyotes
(Canislatrans),andwolvesaretrappedeveryyearinCanada[78],mostlyinkillingnecksnares[2].
ThousandsmorecanidsaresnaredintheUnitedStates[79].Killingnecksnaresplayanimportant
roleinthecaptureofthousandsoffurbearers,andtheycauseinjuriesassevereasthoseassociated
withtheoutlawedsteeljawedlegholdtraps:majorsubcutaneoussofttissuelacerations,severe
internalorgandamage,boneandtoothfractures,jointdislocations,andhaemorrhages[11].These
trappingdevicesshouldhavebeenincludedintheoriginalAIHTSandshouldbeincludedinfuture
trappingstandardstoensurethattheymeetthesamescrutinyandTIUthresholdsasothertrapping
devices.
SeveralothermammaltrappingdevicesarenotcoveredbytheAIHTS.Forexample,underwater
traps(killingdevicesorrestrainingtrapsusedaskillingdevicesindrowningsets)receivedlittle
attentioninthepast,eventhoughtheadequacyofdrowningasakillingmethodhasbeenquestioned
[80,81].Manytypesoftrapsareexcludedbecausethefurofthetargetspeciesisnottraded,e.g.,traps
usedwithratsandmice,includingbreakbacktraps,glueboards,multicapturemousetraps,and
bamboorattraps.
5.Hypothesis3:TheAIHTSAnimalWelfareIndicatorsandInjuriesAreInsufficient
MasonandMendlpointedoutthattheassessmentofanimalwelfarereliestoooftenon
subjectivejudgements[82].Animalwelfareindicatorsandinjuriesusedintheassessmentoftraps
mustreflecttheextentofscientificknowledgeabouttheanatomy,physiology,andbehaviourof
sentientorganisms.TheAIHTSaimedtoequipresearcherswithobjectivequantitativemethodsto
assesswelfare,suchasaninjuryscoringsystemforrestrainingtraps[60]orTIUsforusewithkilling
traps[3].Nevertheless,recognizingthatbothnonlethalandlethalmethodscanaffectwelfare,Mellor
andReiddevelopedthefivedomainsmodel(originallybasedontheUnitedKingdomFarmAnimal
WelfareCouncil’sFiveFreedoms)[83].Themodelassistsinidentifyingwelfareimpactsunderthe
followingdomains:nutrition,environment,health,behaviour,andmentalstate[83,84].Thesefive
areascouldbeintegratedintotheAIHTStohelpbetterquantifythewelfareimpactsoftrapping.
Theassessmentofrestrainingtrapsshouldnotbelimitedtoinjuriesincurredinatrapbutshould
alsoincludethelongtermeffectsoftrappingonanimalsthathavebeenreleasedbythetrapperor
researcher.Forexample,theNo.3VictorSoftcatchTMpaddedfootholdtrapappearedtocauselittle
ornoinjuriestoRuppell’sfoxes(Vulpesrueppellii)whenindividualanimalinjuryrateswere
considered[85].However,subsequentcagetrappingshowedthatfootholdtrappingcouldlowerthe
survivalrateofthesefoxesforaperiodof6monthsfollowingtheirrelease[85].Similarly,significant
capturerelatedeffectsinursidsmaygoundetectedatthetimeofcapture,thusprovidingafalse
senseofthewelfareofreleasedanimals[86].Cattetetal.[87]reportedontheincidentaldiagnosisof
exertional(capture)myopathyinagrizzlybear(Ursusarctos)thatdiedapproximately10dafter
capturebylegholdsnare.Thesameresearchersfoundthatserumconcentrationsofaspartate
aminotransferase(AST)andcreatinekinase(CK),biochemicalindicatorsofmuscleinjury,were
abovenormallevelsinahigherproportionofapparentlyuninjuredgrizzlybearsandblackbears(U.
americanus)capturedinlegholdsnaresthanthosecapturedbyhelicopterdartingorbybarreltrap
[86].Inaddition,therateofmovementsmadebybearsdecreasedbelowmeannormalrate
immediatelyaftercaptureandthenreturnedtonormalonly3–6weeksafterrelease[86].Researchers
determinedthatgreywolves(Canislupus)capturedinfootholdtrapsandcablerestraintdevices
(modifiednecksnareswithastoptoavoidasphyxiation)restrictedtheiractivityandmovement
patternsfor8–10dfollowingcapture[88].Suchbehaviouralchangescouldhavesignificantimpacts
onthereproductionperformanceandsurvival(e.g.,bynotsecuringtheirminimumdailyfoodintake
ormaintainingtheintegrityoftheirterritory)ofanimalsthatwererecentlycaptured.
Inthecaseofrestrainingdevices,physiologicalinvestigations(e.g.,analysisofbloodcollected
fromcapturedanimalsincompoundtestsorwhenretrievinganimalsinfieldtests)mayprovide
Animals2020,10,126213of26
researcherswithabetterunderstandingofthegeneralconditionoftrappedanimalsandbeusedto
validateconclusionsreachedusinginjuryscoringsystems[89].Itispossiblethatassessmentsbased
entirelyonphysicalinjuriesmaynotbeadequatetoassessparticulartrappingdevices[60].Inthis
regard,persistentchangesinthehematologyandserumbiochemistryofgrizzlybearshavebeen
showntobedirectlyrelatedtothenumberoftimesabearwascapturedbylegholdsnareandthe
timeintervalbetweensequentialcaptures[90].Physiologicalinvestigations(e.g.,
stress/glucocorticoidassessments)mayassistintheselectionoftrappingdevicesforaspecific
conservationprogram[60].TheAIHTSrecognizedtheneedtostudybehaviouralandphysiological
changesduringandaftertrapping.Twentyyearslater,however,therearenoacceptancecriteriain
place.
TheAIHTSidentifyselfmutilation,excessiveimmobility,andunresponsivenessasbehavioural
indicatorsofpoorwelfare.Thislistofindicatorsisclearlyinadequatetoassessthewelfareof
restrainedanimals.Signsofdistressmayincludevocalization,carnivoresfeedingonplantmaterial
becausetheyaredehydratedorhungry,thepostureoftheanimalsfromthebeginningtotheendof
thecaptureperiod,andchangesinthealertnessofanimalsatsunriseorsunsetorwhenotheranimals
passby,etc.[2].Behaviouralchangesmaybeinvestigatedduringcompoundtests,orinthefield,
usingrecordingswithvideocameras[2,29].
Whereasalongtermeffectoflivetrappingonreleasedanimalsmightbeexpected,theimpact
ofkillingdevicesonanimalswhichescapemustalsobetakenintoconsiderationwhenassessing
traps.Forexample,killingnecksnaresdonotquicklyrendercanidsunconscious[12],andwhenneck
snaredcanidsescape,theyusuallydiefrominfectionand/orstarvationhoursordaysafterescaping
[2].Theprobabilityofanimalsescapingfromkillingtrapsneedstobeassessedaspartofanyapproval
process.
6.Hypothesis4:TheAIHTSTestingProceduresAreNeitherThoroughNorTransparent
Alltrappingdevicesthatsuccessfullypassedmechanicalevaluations,approachtests,and
compoundtestsintheCanadianresearchprogramwerealsosuccessfulinfieldtests[36,45,46].This
stepwiseapproach(Table1)ensuredthattrapswouldbeproperlytestedandthenumberofanimals
usedintestswouldbeminimized.Nevertheless,itwasnecessarytousesomeanimalsincompound
teststoassesstrapsanddeterminepathologicalchangesthatareassociatedwithspecificstrikesin
vitalregions.Suchinformationcannotbeobtainedwithouttheuseofanimals.Forexample,by
comparingstrikelocationsandlesionsinducedbythetrapforcompound‐andfieldcaughtAmerican
martens,itwaspossibletomakestronginferenceswithrespecttothewelfareoffieldtrapped
animals.Intheabsenceofbackgrounddataontrapsfromcompoundstudies,itwouldhavebeen
nearlyimpossibletoassesstheprobableTIUsusingfieldcaughtanimals,exceptincaseswherethere
weremassivecranialfractures[36,91].
TheAIHTSallowfortheuseofotherscientificallyprovenmethodsasasubstituteforthetesting
proceduresreportedinTable1.SeveraltrappingdeviceshavebeencertifiedbytheCanadianfur
industry[92]onthebasisoftheAIHTS,usingcomputerprogramsthatallegedlyreplicatethe
interactionofaparticularspecieswithacomputerdrawntrap,thusminimizingthenumberoflive
animalsrequiredfortheassessment[93].However,therearenopeerreviewedscientificpublications
oncomputercertifiedtraps.Predictinghowanimalsapproachtrapsvariesamongspeciesand
betweentrapmodelsandcanbeaccurateonlyaftermanyhoursofbehaviouralobservations,aswas
documentedduringthedevelopmentoftrapsforAmericanmartens[30]andfishers[94].For
example,ProulxandBarrett[44]showedthatfisherscanescapefromalateralheadstrikebytwisting
theirheadwhilepullingoutofthetrapatfiringtime.Inaddition,theyfoundthatonlydorsoventral
headstrikesweresuccessfulifthetrapcouldgeneratebothalargeimpactmomentumandalarge
clampingforce.Withoutcompoundevaluationswithliveanimals,computeranalystswouldnothave
beenabletopredictthefisher’sheadtwistingbehaviour.Inotherwords,atrappercouldhaveused
computercertifiedtrapmodelsonatraplineandsurmisedthatallheadstrikesweresuccessfulin
quicklyrenderingfishersunconscious,whereas,inreality,somemayhaveescapedwithhead
injuries.Likewise,aseriesofcompoundtestsshowedthatanarrowmousetrapwithastrikingbar
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poweredbyacoilspringcouldnotrenderredsquirrelsirreversiblyunconsciouswithinapre
determinedtimeperiod.Themanufacturerrecommendedsettingthetrapperpendiculartoapoleon
theexpectationthatasquirrelrunningupthepolewouldsteponthetriggerlaidoverthepoleand
wouldbestruckbythestrikingbar.However,compoundtestsshowedthatthetrapcouldnot
consistentlystrikeredsquirrelsinvitalregionsbecauseoftherapidmovementsmadebytheanimals
aroundthetimethatthetrapwastriggered.Duringaseriesofapproachtests,thetrapanditsset
weremodifiedtobringtheanimalstoafullstopatfiringtimewhenthetrapwastriggered.Thetrap,
baitedwithapineconeandequippedwithsidewings,thenproperlypositionedsquirrelsforahead
strike[47].Thepineconemustbesmallandplacedbetweenthetipsofthetriggerprongsinorderto
forcetheanimalstokeeptheirheadslowandawayfromthecoilspring,thusallowingformore
powerfulhead