BBC Wildlife - UK (2020-05)

T

hepastdecadehasseenan

accumulationofhigh-profileand

influentialstudiesshowingthatocean

acidification– theresultofCO2emissions

dissolvinginseawater– disruptsbasicfish

behaviour.Butaccordingto newresearch,

mostofit is wrong.

Acidificationhasbeenreportedto

interferewithsmell,hearing,visionand

activitylevelsinfish,especiallyincoral

reefspecies.Onewell-publicisedstudy

foundthatit causedfishto swimtowards

predatorsratherthanawayfromthem.

TimothyClarkofAustralia’sDeakin

Universitysayshisinterestwasraised

bytheunusuallystrongeffects

ofCO2identifiedinthe

studies.“Yettherehad

beennoattempt

byindependent

researchgroups

to replicate

theseprofound

findings.”

Workingwith

aninternational

teamof

colleagues, Clark

embarkedona three-yearprojecttodo

exactlythat.Andnow,afterexperiments

onmorethan 900 fishbelongingtosix

species,usingautomateddatacollection

techniquestominimisehumanerror

andbias,theyhaveconcluded

thatCO2hasvirtuallyno

effectonanyofthebehaviours

previouslyreported.

Clarkis concernedthat

anincreasingpressureon

scientiststo“publishor

perish”hasencouragedsome

questionablepractices.

“Itis absolutelycriticalthat

scientistsdoeverything

possibleto make

suretheyget

thingsright,as

otherwiseit feeds

thegrowingpublic

scepticismof

scientists,especially

intheclimate

changerealm,”he

says.“Itis possible

thatsomescientists

think that the end

justifiesthemeans,sothescientific

rigourcomessecondto thestory.”

ButPhilipMundayofAustralia’sJames

CookUniversity,whowasinvolvedin

many ofthestudiesnowbeingcalled

intoquestion,warnsagainst

puttingtoomuchfaithin

thenewanalysis.“Theyused

differentspecies,differentlife

stagesandchangedmethodsin

waysthatcouldfundamentally

altertheresults,”hesays.He

is unwillingto expandonthis,

though,untilhehaspublished

a formaldefenceina journal.

Meanwhile,Clarkmaintains

thatoceanacidificationdoes

notmeaningfullyalterfish

behaviour.“Therearemuchgreater

threatsfacingcoralreeffishes,suchas

oceanwarming,habitatdestructionand

pollution,”hesays.“Thesefactorsdeserve

moreofourresearchattentionwitha goal

to conservecoralreefsandallthewildlife

theysupport.”StuartBlackman

24 BBC Wildlife May 2020

WILDNEWS

Reef: Gary Bell/Oceanwide/Minden/naturepl.com; spiny chromis: OceanPhoto/FLPA; snails: Chester Zoo; sea otter: Anaspides Photography – Iain D Williams/Alamy

FINDOUTMORE

Nature:go.nature.com/34jBosI

Oceanacidication

maynotmesswith

coral reef sh aer all.

MARINELIFE

D I D Y O U

KNOW?

Theworld’soceans

absorbed 34 billion

tonsofcarbonfromthe

atmospherebetween

1994 and2007,about 31

percentofallemissions

during that time.

Theacidtestofstrange

sh behaviour

Previousstudiesrevealed

coralreeffishweresus-

ceptibletoacidification

buta newpaperdisagrees.

Below:spinychromiswas

oneofthespeciesincluded

in the latest research.