Wild salmon on Canada's west coast are being driven to extinction by parasites from nearby fish farms

Wild pink salmon around the Broughton Archipelago are declining rapidly and will die out within 10 years if no action is taken, say researchers.

They say the data, published in Science, raises serious concerns about the global expansion of aquaculture.

Sea lice from farms are known to infect wild salmon, but until now the impact on wild populations has been uncertain.

"The impact is so severe that the viability of the wild salmon populations is threatened," said lead researcher Martin Krkosek from the University of Alberta in Edmonton, Canada.