Killer whale pop­u­la­tions un­der threat from plas­tic

Sunday Sun - - News -

THE num­ber of killer whales could be halved in a few decades due to pol­lu­tants in the seas, ac­cord­ing to new re­search.

Steps to ban chem­i­cals – known as poly­chlo­ri­nated biphenyls (PCBs) – were first made 40 years ago, but they re­main a deadly threat to the mam­mals at the top of the food chain.

A new study, in­volv­ing re­searchers at the Univer­sity of St An­drews, shows cur­rent con­cen­tra­tions could se­verely de­plete pop­u­la­tions of killer whales in the most heav­ily con­tam­i­nated ar­eas within 30 to 50 years.

Pro­fes­sor Ailsa Hall, di­rec­tor of the Sea Mam­mal Re­search Unit, said: “In these con­tam­i­nated ar­eas, we rarely ob­serve new­born killer whales.”

Or­cas are among the mam­mals with the high­est level of PCBs in their blub­ber, with val­ues as high as 1,300 mil­ligrams per kilo­gram.

An­i­mals with lev­els as low as 50 mg per kg can show signs of in­fer­til­ity and im­mu­nity prob­lems.

Re­searchers from St An­drews and Aarhus Univer­sity in Den­mark found the num­ber of killer whales could rapidly de­cline in 10 of the 19 pop­u­la­tions.

They are par­tic­u­larly threat­ened in heav­ily con­tam­i­nated ar­eas near Brazil, the Strait of Gi­bral­tar, the west coast of the UK, and along the east coast of Green­land.

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