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Galeusmelastomus Scyliorhinuscanicula

Variabilityintypesofingestedplastic

DarkFilaments LightFilamentsTrasparentFilaments DarkFilmsLightFilms TrasparentFilmsDarkFragments LightFragmentsTrasparentFragments DarkSpheresLightSpheres TrasparentSpheres

Occurrenceofmicroplasticsingestionbydeep-watercatsharksGaleusmelastomusandScyliorhinuscanicula(Chondrychtyes)intheTyrrheniansea(WesternMediterranean)

ValenteTommaso1*,BianchiJessica12,SilvestriCecilia1,ScaccoUmberto1,deLuciaGiuseppeAndrea3,CameddaAndrea3andMatiddiMarco11ISPRA,ItalianNationalInstituteforEnvironmentalProtectionandResearch,ViadiCastelRomano100,00144,Roma,RM,Italy.

2DepartmentofEcologyandBiology,UniversityofTuscia,ViaS.CamillodeLellis44,01100,Viterbo,VT,Italy.3IAMC-CNR,InstituteforCoastalMarineEnvironment–NationalResearchCouncilLoc.SaMardini,09170,Torregrande,OR,Italy.

*Correspondingauthor.E-mailaddress:tommaso.valente@isprambiente.it

References

Nowadaysplasticdebrismustbeconsideredanubiquitouselementofmarineecosystems,distributedbothinshallowanddeep-water.Differentdietstudiessuggestthatsharksandrayscouldbethreatenedbyplasticingestion.Blackmouthcatshark(Galeusmelastomus)andlesser-spottedcatshark(Scyliorhinuscanicula)aretwoabundantdeep-water

elasmobranchs,bothopportunisticscavengers,whosefeedinghabitshavebeenwidelystudiedinoverlapsanddifferences.Theaimofourstudyistoverifyanydifferencesinfrequencyandmodalityofplasticsingestionbythetwospecies.

Materialsandmethods

Samplesresultfromaby-catchofprofessionalottertrawlertargettinggiantredshrimpsatdepthbetween400mand500m.

.

To avoid secondary contamination, a Tyvek® protective suit was used during the labanalysisandthesampleswereprocessedunderalaminarflowcabinet.Furthermore,alllaboratory instruments and tools were washed with rinsed water and checked everytime,alsotopreventcross-cotamination.

The nature of suspected items were determined using Fourier Transformed Infraredspectrometry(FT-IR).

Fishes were dissected and the GI tract was removed. The GI tract was placed intoindividualglassjars.EachsamplejarcontainingtheGItractwasfilledto3×thevolumeofthetissuewitha10%KOHsolutioninultrapurewaterandincubatedovernightat60°Ctodigestorganicmaterial(Rochmannetal.,2015).

Then digestates were filtered through a vacuum pump and plastic debris has beenidentifiedusingastereomicroscope.

Introduction

Results

Rochman,C.M.,Tahir,A.,Williams,S.L.,Baxa,D.V.,Lam,R.,Miller,J.T.,Teh,S.J.(2015).Anthropogenicdebrisinseafood:Plasticdebrisandfibersfromtextilesinfishandbivalvessoldforhumanconsumption.Scientificreports,5.AnastasopoulouA.,MytilineouC.,SmithC.J.,PapadopoulouK.N.(2013).Plasticdebrisingestedbydeep-waterfishoftheIonianSea(EasternMediterranean).Deep-SeaResearchI,74,11-13.

Filaments-like are the most frequent items. Considering color and shape of items,Galeusmelastomus(H=1.50)showsagreatervariabilityintypesofingestedplasticthanScyliorhinuscanicula(H=1.12).

ThecomparisonbetweenthetwospecieswasmadeconsideringdataonFrequencyofOccurence(chi-squaredtest),abundance(Kruskal-Wallisranksumtest)andvariability(calculationofentropyindex,H)ofingesteditems.Relationsbetweenplasticingestionandpotentialbiologicalandecologicalpredictorsarenotexaminedhere.

Infrared spectrum ofmicroplastic polymer (polypropylene) found in Scyliorhinus caniculaandGaleusmelastomussamples

Preliminary results confirm that plastic ingestion occurs in both species, withoutsignificativedifferences intermsoffrequencyofoccurence(p>0.05)andabundanceofingesteditems(p>0.10).

44,8%28,6%

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Galeusmelastomus

Scyliorhinuscanicula

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uencyofOccurrence(%

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Sampleswithingestedplastic

57%

10%

26%

7%

IngestedLitterComposition

Filament Film Fragment Sphere

Fibers Films Fragments SpheresG.melastomus 29 44,8% 0.62 0.10 0.17 0.10S.canicula 28 28,6% 0.21 0.03 0.21 0.00

IngestedMarineLitterperSample(Abundance)Species Samples FO

Conclusions Thepresentedpreliminaryoverviewshowshowdeep-watercatsharksarethreatenedbyplasticingestion.Theobserveddifferencesinthevariabilityofingestedplasticbythetwospeciesprobablyreflectsdifferencesinfeedinghabits.Thedetectionofplasticsinthefinalpartofthegastrointestinaltractofbothspeciessuggeststhattheseanimalscanexpelplasticswiththefecesandnoformofgastricblockagehavebeenobserved.Studiesareinprogresstobetterinvestigatethephenomenon.