Rescuing Fish from the Murray River

Extreme flooding along the Murray River and its tributaries during late 2022 caused a major environmental crisis, triggering what is known as a hypoxic blackwater event^.. These events occur when large amounts of organic material—like leaves and debris—are swept into the waterways by floodwaters. As this material breaks down, it strips oxygen from the water, creating lethal conditions for aquatic life.

Faced with plummeting oxygen levels, Murray crayfish and native fish began to surface in distress. Crayfish were seen leaving rivers, sometimes even climbing trees or making their way across paddocks, as they tried to escape the deoxygenated water. Many fish, losing their color and often seen floating, were on the brink of death.

In response, the community group OzFish Unlimited, together with state authorities and local volunteers, launched an emergency rescue operation. Teams worked around the clock—sometimes covering up to 500km a day—netting distressed fish and gathering crayfish for temporary relocation. More than 1,500 freshwater crayfish and hundreds of native fish were saved during this effort. The rescued animals were cared for at private aquaculture sites until river conditions improved, after which they were returned to their natural habitat.

Rescue operations covered large stretches of the river, from Mildura up to Barham, often under challenging and emotionally taxing conditions. Volunteers described the effort as both overwhelming and inspiring, with many feeling a strong sense of duty to protect the river’s unique wildlife.

However, experts warn the impact of these blackwater events is likely to be long-lasting. The Murray crayfish, which can take up to nine years to reach maturity, are especially vulnerable. Past events have set back their populations by a decade or more. OzFish and partnering agencies continue to work on long-term habitat restoration to help accelerate recovery for the affected species.

These rescue missions highlight the importance of community action and coordinated response in the face of natural disasters that are becoming more frequent and severe with climate change. Locals are encouraged to monitor waterways, report sightings of distressed wildlife, and get involved in ongoing conservation efforts.

The events serve as a stark reminder of how interconnected river health, land management, and local communities are—and how quickly that balance can be disrupted when nature’s systems are under extreme stress.