SharkSightings

Indeeperwater,Gajićhasencounteredbizarre-lookingroughsharksandlanternsharks.Gajićdoesn’tneedhispowerfulcameralighttoseelanternsharks.Theyglow!Theyarelittlefish,nobiggerthan50centimeters(about20inches)long.Thelightcomesfrommanysmallorganscalledphotophores,whichdottheirbelliesand sides.


Gajić’sinteractionswithraysandskatesarealittlelessproblematicthanwithsharks.He’sabletogetclosertorays,inparticular.Heinteractswithcommonstingrays,eaglerays,andleopardwhipraysashestudies them.


ForGajić,itisadreamcometruetobeamongtheseanimals.HegrewupinwartornYugoslavia.Hisfamilymovedmanytimeswhenhewasyoung,alwayslookingforasaferandmorestableplacetobe.Heneverlivedanywhereneartheocean.Yet,hewasfascinatedbytheseaandwhatlivedinit,especiallysharks.HewasinspiredbycopiesofNationalGeographicmagazine.Hevowedonedaytovisitsomeofthemagnificentplaceshesawinthemagazineandtoonedayswimwith sharks.

researchingunbornsmoothhound sharks

Gajićexaminesadeep-waterroughsharkinthe lab. 

DangerousWaters

Asmuchashelovessharks,GajićknowsthattheyareintroubleintheAdriatic.Pollutioniscausingillnessesinmanymarineanimals.Plastics,pesticides,heavymetals(likelead),andwastepoisonthesea.AndintheAdriatic,warwasteammunition,grenades,bombsalsocontaminatesthewater.ThecoastlinealongNeumisapopularvacationspot.Yet,muchofthetown’ssewageflowsintotheseasomeofitisunfilteredwaste.Combined,thesefactorsmakeconditionsforsealife hazardous.


Outwardly,amarineanimalmightseemhealthy.Toknowforcertain,Gajićmusttakeoffhisdivesuitandputonhiswhitelabcoat.Inthelab,heexaminessharkorgansandtissuethroughapowerfulmicroscope.Onlythencanheseewhat’sreally happening.

UndertheMicroscope

Gajićrarelycollectssamplesfromlivesharks.Ifheneedsatissuesample,itistakenfromanalready-deadshark.Thesecomeintheformofbycatchwhenasharkisaccidentallycaughtinafisher’snetandkilled.ManyofthelocalfishersknowthatGajićisstudyingsharksandtheirhealth.Whenasharkiscaughtbymistake,theycontacthim immediately.


Inthelab,eachspecimenisgivenafullxrayandaCATscan.Tissuesamplesaretaken.Fromthesesamples,Gajićcanlearnalot.Inoneshark,hefoundanusualamountoffatintheshark’sliver.Itisnormalforthattypeofsharktohaveupto50percentoffatwithintheliver.Thissharkhadfarmorethanthat.Inanothershark,hefoundthediseasehepatitis.That’saninflammationoftheliver.Itmightbecausedbyhighconcentrationsofheavymetalsinthewater.Inothersharks,hefounddiseaseinbothkidneyandbraintissue.Atoneparticularsite,around90 percentofthetissuessampledshowedsomeevidenceof disease.

ThissevengillsharkwasbycatchoffthecoastofMaltaintheMediterranean Sea.