Australia Launches Clean-Up Efforts After Mass Fish Deaths in Menindee River.

Millions of fish have died in a river in western New South Wales, Australia, due to low oxygen levels caused by hypoxic blackwater, a naturally occurring phenomenon. A major clean-up effort is under way, with fish being cleared from "high density areas", but it will not be possible to remove all the carcasses. The water supply remains "high quality", according to police. The Darling-Baaka River forms part of the Murray-Darling Basin, which is Australia's largest river system and has faced pressure from drought and increased human use in recent years.