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IntraguildPreda.onofAtlan.cmackerelonearlylifestagesofanchovyandsardine
E. Bachiller*, E. Cuende, P. Álvarez, A. Fontán, N. Rodriguez-Ezpeleta, U. Cotano
IntraguildPreda.onasregula.onmechanism
Ecosystem-basedfisheries
managementInter-annual&long-term
varia.onsinsmallpelagicfish
Bakun’sTRIADconcept(1993):Reten.on,Produc.on,Concentra.on
TROPHICINTERACTIONS?Compe..onforfood
Intra-&inter-specificpreda.onIGP
NortheastAtlan.cmackerel
Maturity: age 2-3yr
Summer Feeding Migration
• Trophicnichebreadth↑• Stom.contents↔availableprey• Feedingincidence↑• Consump.onrate↑
NEAmackerel:trophicstudies
Pre
y dr
y w
eigh
t (m
g)
• Opportunis.cpreda.on(BoB&NS)• Spa.aloverlap↑poten.aleffects↑
Fishegg&larvaepreda.onbyadultNEAmackerel
2008-2009Pc(ane)=36%Pc(ane)duetoMAC=7%Omac-ane↓
2013In45%ofguts23%oftotalpreyW
IGPeffectsonELSofanchovyandsardine?
IGPeffectsonELSofanchovyandsardine?
• Highdiges.onrate• Highregurgita.on• Timeconsuming…
Newmethods,newinsights
qPCR
qPCR
• 6outof238mackerellarvaecontainedDNAofsardineinstomachcontents.Ø NOspa>aloverlapfoundinsamples!
Butwindregimecouldchange…• NoneshowedDNAofanchovy.ü Usefulmethodforpreydetec.on(valida.onok)
Preliminaryresults…
Newmethods,newinsights
+ DNAM
ETABARCODIN
G
• 19species(groups)• Fisheggspresentin22indiv.(44%)
§ >10eggsin9stomachs§ Max=152eggs
Preliminaryresults…
N=40indiv.
• 19species(groups)• Fisheggspresentin22indiv.(44%)
§ >10eggsin9stomachs§ Max=152eggs
• Norecognizablesardineeggs/larvae
• 19species(groups)• Fisheggsin22indiv.(44%)
§ >10eggsin9stomachs§ Max=152eggs
• Nosardineeggs/larvae
Preliminaryresults…
N=40indiv.
• 176species(groups)• 14fishspeciespresentin97%
§ Hakepresentin71%ofsamples§ Horsemackerel(26%),flatfish(17%)...
• Nosardineeggs/larvae
Preliminaryresults…
N=40indiv.
• 176species(groups)• 14fishspeciespresentin97%
§ Hakepresentin71%ofsamples§ Horsemackerel(26%),flatfish(17%)...
• Nosardineeggs/larvae
+24indiv.(commercialfishingvessels)
Sardinepresentin>50%mackerel!
Preliminaryresults…
N=47indiv.
• 22species(groups)• Fisheggsin17indiv.(36%)
§ Anchovyeggsin11stomachs(24%)• Anchovyjuvenilesin4indiv.(8.5%)
• TheELSsurvival(&recruitment)ofclupeoidscanbenega.velyaffectedbymackerel(larvae&adult)preda.on.
• IGPeffectsaremostlydependentonspa.o-temporaloverlap(opportunis.cpreda.onbymackerel).
• Combina.onofvisualanalysisandmetabarcodingonstomachcontentsprovidenewinforma.onwhichcouldbeessen.altobeperunderstandtrophicinterac.ons.
Preliminaryconclusions
• Uniden.fyable(highlydigested)preycanbedetected
• Cost-effec.ve
• Quan.fica.on?• Cannibalism?• ‘Preyofpreys’?
• TheELSsurvival(&recruitment)ofclupeoidscanbenega.velyaffectedbymackerel(larvae&adult)preda.on.
• IGPeffectsaremostlydependentonspa.o-temporaloverlap(opportunis.cpreda.onbymackerel).
• TheELSsurvival(&recruitment)ofclupeoidscanbenega.velyaffectedbymackerel(larvae&adult)preda.on.
• Intensivesampling(spa.o-temporaloverlap)• IGP(visus+gene.ctools)vs. Omac–pil&ane(windregime…) sardine&anchovyELSsurvival mackerelrecruitment
Ø Incorporatesuchinforma.ontomul.species/ecosystemmodelingtools…
Foodforthought…
ThanksforyouraIen.on
