NowoutoftheclearblueseasofftheislandsofPolynesiawherescientistshavediscoveredanareateemingwithsharks,normallythereisanaturallybalancewithlotsofpreyandfewerpredators,butnotsointhiscase.OursciencereporterJonathanWebtoldushowthisdiscoverycameabout.

Well,actuallyscientistswenttothisatall.Anditisanusuallittleplace.Thereisachannelrunningthroughthemiddleofit,quiteasmallchannelonlyaboutthirtymetresdeep.Theywenttherebecauseadifferenttypeoffishnotsharksinfactbutagroupoffishareknowntospawnthere.Theywenttherethinkingtheyweregonnastudythosefish.Theyendedupfindingahugeconcentrationofgreyreefsharks,ahigherconcentrationtwoorthreetimeshigherthanit’sbeenfoundanywhereelseintheworld.Andsotheysaidabouttryingtounderstandwhatwasgoingon.Theytaggedsomeofthesharks.Theydidasortofcensusofthechannel.Becausethatabundanceof,sortofpeakpredatorifyoulike,somethingrightatthetopofthefoodchainisreallyhardtosustain.Normallyifyouaddupthebiomassinaparticularecosystem,there’llbemuchmuchmoreofthethingsdownthebottom,lotsandlotsofpreyandasyou’resayingnotverymanypredatorsso…

Sowhydotheythinkthishappened?

Yes,sotheytriedtoworkoutexactlywhatwasgoingonanditturnsoutthatthosespawningfish,theonesthattheywenttheretostudyinthefirstplacewereeffectivelygivingagreatbigdelivery.Everywintertimethosefishwould