HowBadIsIt?
In2010,scientistsnamedthelionfishinvasiononeofthetop15threatstoglobalbiodiversity.Thatmeanslionfisharecapableofcompletelychanginganentireecosystem.Andtheyhave.Insomeplaces,lionfishhavereducednativefishpopulationsby80percent.Howisthat possible?
Lionfishdon’tactlikesomeotherpredators,whicheatalotallatonceandthendon’thuntforseveraldays.Lionfishneversaynotofood.Theycaneatonetotwofishperminute.Overa year,thisworksouttohundredsofthousandsoffisheatenperacrejustby lionfish.
Whiletheyfeedmostlyonsmallfish,lionfishcanwipeoutentiregroupsofcrustaceans,suchasshrimps, too.
Theyalsoeattheyoungoflargerfish.Thismakesithardforsomeendangeredorthreatenedspecies,liketheNassaugrouper,torebuilditspopulation.Thisisespeciallytruewhenthegrouperisalreadycompetingwithlionfishforlivingspaceon reefs.
Alionfishswimsnearamangrove forest.
NewRules
Lionfishbehaveinunexpectedways.Thismakesthemmoredangerousthanpredatorsthat“playbytherules.”Here’sanexample.Mangroveforestshavealwaysbeenasafehavenforyoungreeffish.Thesestretchesofseabetweenriversandoceansarebrackish.Thatmeanstheyareamixoffresh-and saltwater.
Theseunderwaterforestsofmangroverootsprovidebabyfish,orfry,withfoodandcover.Mostoceanpredatorsdon’thuntthere.Thelionfishhuntstherewithease,roamingaroundandhooveringupsmall fish.
Thisyoungsnapperisbeingcleanedby humpbackcleaner shrimp.
Lionfishdisruptreefbehavior,too.Forexample,somelargerfishlineuptogetparasitespickedoffofthembysmallerfishsuchasblueheadedwrasses.Thesecleanerfishgetaneasymeal.Thelargerfishgetcleanandenjoybetter health.
Aspartofthebargain,thelargerfishdon’teatthecleanerfishwhiletheworkisbeingdone.Thisisasafetyzoneforthesesmallerfish.Butlionfishsimplyseethesestationsasbuffets.Theyswimintothestationsandscarfupanyfishthatwillfitinsidetheir jaws.
Fisharen’ttheonlyorganismsthreatenedbylionfish.Manyreefcoralsarealsounderattack.Whenlionfisheattoomanyplanteatingfish,there’snothingtoeatthealgae.That’swhenthealgaegrowoutof control.
Algaecoverthecorals,chokingoffthelightthatcoralsdependupon.ThishappenedintheBahamasbetween2003and2009whenlionfishatetoomanyyoungparrotfish.Thealgaegrewsomuch,itkilledthecorals.Itcreatedachainreaction.Itledtoaseriouslossofhabitatforallreef creatures.
Theselionfishcrowdtogetherononecoral reef.
