Millions of fish die in a large-scale fish death event in New South Wales, Australia

Millions of fish have died in another mass kill in the lower Darling-Baaka river near Menindee, New South Wales, Australia last week. The area has been the site of several other mass fish kill events in recent years but the latest fish kill appears larger than the previous.

The NSW Department of Primary Industries said on Friday, March 17, 2023, there was a “developing large-scale fish death event” affecting millions of fish below the Menindee main weir through to weir 32, adjacent to the Menindee township. A department spokesperson said the deaths were due to low oxygen levels in the water as flood waters receded.

The Murray-Darling Basin, which spans four Australian states, is a crucial source of water for agricultural industries. However, years of over-extraction, drought, and policy failures have resulted in severe ecological damage to the system.

Murray Lower Darling Rivers Indigenous Nations (MLDRIN) spokesperson Philip Sullivan said the latest fish kill was “a catastrophic failure of policy and governance”. He called for “urgent action” to address the ecological crisis in the region.

The incident has sparked renewed criticism of the Australian government’s management of water resources, with Environment Minister Sussan Ley facing calls to address the long-term sustainability of the Murray-Darling Basin.

Ley responded to the fish kill, saying the government is “committed to the health and wellbeing of the Murray-Darling Basin” and will work with stakeholders to address the issue.

However, environmental groups and Indigenous leaders argue that more needs to be done to address the root causes of the crisis, including over-extraction of water, the impacts of climate change and lack of effective governance.

Associate Professor Joy Becker,  from the University of Sydney’s School of Life and Environmental Sciences, calls for an investigation to determine the cause of the mass death of fish. She suggests that fish kill events occur when the environment cannot sustain fish life and that such events impact not only large fish but also small fish essential to a healthy aquatic ecosystem.

The investigation should focus on examining the water quality parameters like temperature, dissolved oxygen levels, PH, and nutrient levels of the water body where the fish kill occurred. The presence of pollutants like pesticides, heavy metals, and industrial waste should also be tested. The evidence collected during the investigation can help determine the cause of the fish kill event and identify potential sources of pollution in the water body.

It is critical to address the root cause of the fish kill event to prevent future incidents and protect the aquatic ecosystem.

References:

¹ ‘Unfathomable’: millions of dead fish blanket river near Menindee in latest mass kill – The Guardian – March 17, 2023

Featured image credit: ABC News (stillshot)