The cause of the mass fish deaths in Menindee, New South Wales, Australia, has been traced to depleted oxygen levels in the water, according to the NSW Department of Primary Industries. Millions of fish, primarily Bony Herring, and smaller numbers of other large-bodied species, including Murray Cod, Golden Perch, Silver Perch, and Carp, have succumbed. The hypoxia, or low oxygen levels, is believed to have occurred after flood waters receded, enabling concentrations of fish, nutrients, and organic matter to return to the river channel. The current heatwave in western NSW is making the situation worse, as warm water requires greater oxygen than colder water. The fish deaths threaten to render the water unsuitable for human use, and the magnitude of the loss has been described as “unfathomable.” An investigation into the cause of such events is needed to comprehend why the environment cannot sustain fish life, according to Joy Becker, an associate professor at the University of Sydney.
Large numbers of dead fish found in Australian river.
