BBC Wildlife - UK 2020-07)

Right:swimmingwithsharks.

Below:transmitterswereused

byresearchersfromExeter

Universityin 2007 toattachto

baskingsharksotheIsland

of Coll in the Inner Hebrides.

ISLAHODGSONis a conservation

scientistandguideforBasking

SharkScotland– visitthe

websiteatbaskingsharkscotland.co.uk

FINDOUTMOREDiscovermore

aboutbaskingsharksonourwebsite:

discoverwildlife.com/basking-sharks

behaviourtoconveyinformation.Possibly,

it couldbea signaltoothersharksinthe

areathattheyareavailableformating,or

a displayofdominancebymales.Other

observationsfromDonegalinIrelandseem

tosuggestbreachingis potentiallystimulated

byenvironmentalfactors,suchasseasurface

temperature.Certainly,moreresearchis

neededtostudythisbehaviourinrelation to

sexandotherpotential triggers.

Babyshark

Anothersecretis where,andhow,basking

sharksgivebirth.Fromverylimited

evidence,it appearstheyareovoviviparous,

meaningthatthenew-bornpupbreaksout

oftheeggwhilestillinsidethemother,and

is effectivelybornalreadyhatched.

Theonlyexistingeye-witnessaccount

ofpuppingcomesfromtwoNorwegian

fishermen,HansGoksoyrandJonas

Sordal,in1936.Baskingsharkswere

onceextensivelyhuntedfortheirlarge

andoilyliver– usedinlamps,cosmetics,

andlubricants.Largefisheriesexistedin

Scotland,IrelandandScandinavia,and

exploitationalmostdrovethespeciesto

thebrinkofextinction.

Whiletowinga harpoonedsharkbackto

thefishery,theNorwegianfarmersdescribed

a livesharkbeingbirthedandswimming

away,closelyfollowedbyfourothers,with

oneotherdeadinsidethemother.This

tinysnippetofinformationimpliesthat

baskingsharkshavelittersofuptosixand

arepossiblyK-selected– investingmorein

smaller, but more developed, young. Juvenile

Satellitetransmitters

areattachedtothe

sharks via a pole.

sharkshavebeensighted– conspicuous

fortheirmorepronounced,twistednoses,

whichstraightenoutovertime– however,

theirentranceintothisworldis yettobe

scientificallyrecorded.

Learningmoreaboutthismysterious

speciesis vitaltoitsprotection.

Distinguishingbreeding,matingand

feedingsitescanhelpusidentifypotential

overlap with human activities, informing

protectivemeasuresintheseareas.The

denseaggregationsweobservearound

CollandTiree– aswellasthepossible

matingactivity– suggestthatthisis a

highlyimportantareaforthespecies.A

MarineProtectedArea(MPA)hasbeen

proposedfortheHebrides,toprotectthe

baskingsharkandothermobilespecies

thatdependonthesewaters,suchasminke

whalesandRisso’sdolphins.ThoughMPA

designationsarechallenging– especiallyfor

migratoryspecies– thiscouldprovidevital

safeguardingforanareakeytothebasking

shark’ssurvival.

Backinthegentlyundulatingwatersof

theAtlantic,wewatchthesharkswimpast,

socloseyoucanlookherintheeye.Forone

sobig,shemoveswitheasethroughthe

water,hersizealmosttoomuchforthe

humanbraintocomprehend.Thegirlnext

tomegrabsmyarmandsqueezesit tight.

I turntoseeherbeamingfaceandslightly

fogged-upmask;theothersoverher

shoulderlookjustasexhilarated.The

encounterwasjusta fewseconds,but

nothingcomparestoa 9mshark just

casually passing youby.

July 2020 BBC Wildlife 45