Risky busi­ness for fish in oil-pol­luted reef waters

Kuwait Times - - HEALTH & SCIENCE -

Co­ral reef fish are more likely to en­gage in risky be­hav­ior and be un­able to iden­tify preda­tors if they swim in waters con­tam­i­nated with pe­tro­leum-based oil, re­searchers said. Con­cen­tra­tions equiv­a­lent to only “a cou­ple of drops in a swim­ming pool” could be enough to im­pair their judg­ment, sci­en­tists said in the study pub­lished Tues­day in the jour­nal Na­ture Ecol­ogy & Evo­lu­tion. “The fish were un­able to iden­tify friend from foe and they stopped trav­el­ling in groups,” study co-au­thor Jodie Rum­mer from Aus­tralia’s James Cook Uni­ver­sity’s ARC Cen­tre of Ex­cel­lence for Co­ral Reef Stud­ies said.

“The fishes also had trou­ble se­lect­ing suit­able habi­tats, swam to­ward open waters, and could not swim away quickly from dan­ger.” The re­search, which the sci­en­tists de­scribed as the first of its kind, fo­cused on lar­vae-the ju­ve­nile stage when fish are es­pe­cially vul­ner­a­ble-and on six fish species from Aus­tralia’s Great Bar­rier Reef. The oil con­cen­tra­tions used in the study re­flected “many pol­luted coast­lines in in­dus­tri­al­ized re­gions world­wide”, the sci­en­tists from Aus­tralia, Nor­way and the United States said. The sci­en­tists said the oil ex­po­sure ap­pears to “im­pair higher-or­der cog­ni­tive pro­cess­ing and be­hav­iors nec­es­sary for the suc­cess­ful set­tle­ment and sur­vival of lar­val fishes”.

“This em­pha­sizes the risks as­so­ci­ated with in­dus­trial ac­tiv­i­ties within at-risk ecosys­tems,” they added. “Each year, over six mil­lion met­ric tons of pe­tro­leum prod­ucts are es­ti­mated to en­ter global oceans from an­thro­pogenic sources such as in­dus­trial dis­charge, ur­ban run-off and ship­ping op­er­a­tions.” The sci­en­tists said when the fish were ex­posed to in­creased oil con­cen­tra­tions in the lab tests, there were higher death rates and changed be­hav­ior. With ecosys­tems such as the Bar­rier Reef al­ready un­der pres­sure from co­ral bleach­ing and devel­op­ment, they added that lim­it­ing pol­lu­tion-par­tic­u­larly oil-near reefs was key to pre­serv­ing such bio­di­verse sites.

“If an oil spill were to oc­cur, this study sug­gests there could be ma­jor con­se­quences for reef fish, co­ral reefs, and the peo­ple work­ing in fish­eries and tourism,” lead au­thor Ja­cob Jo­hansen from the Uni­ver­sity of Texas said. “Over the past 35 years, many of the world’s co­ral reefs have de­clined. Still, many govern­ments con­tinue to al­low in­dus­trial ac­tiv­i­ties, in­clud­ing oil drilling and ex­plo­ration, in sen­si­tive reef habi­tats.” — AFP


QUEENS­LAND: A hand­out photo re­ceived from the ARC Cen­tre of Ex­cel­lence for Co­ral Reef Stud­ies at James Cook Uni­ver­sity shows blue-green chromis on the Great Bar­rier Reef near Lizard Is­land in Queens­land.

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