Australia's Iconic Murray Cod Bounces Back After 50 Years

After nearly disappearing from Australia's rivers 50 years ago, the mighty Murray cod is making a stunning comeback that's transforming entire river ecosystems.

The Murray cod is no small fish. Growing up to 1.8 meters long and weighing over 50 kilograms, it's the apex predator of Australia's inland waterways. Even invasive European carp flee when a big cod prowls the Murray-Darling Basin rivers stretching from Victoria to Queensland.

But by the 1970s, overfishing and massive dam projects had nearly wiped them out. Recreational fishers from that era remember going years without seeing a single Murray cod. The species was listed as vulnerable, and Australia's river ecosystems suffered without their top predator.

Today, the story is completely different. A recent electrofishing survey of Victoria's Ovens River found more than 110 Murray cod per kilometer. The Goulburn and Loddon rivers show similarly flourishing populations.

Taylor Hunt, a fisheries manager with the Victorian Fisheries Authority, says the evidence is overwhelming. Scientific surveys and feedback from more than 3,500 anglers tell the same story: cod are everywhere again, and they're thriving.

"We've seen more than two to five times increases in the numbers of Murray cod since the 1990s," Hunt said. In Lake Eildon alone, cod numbers jumped 81 percent between 2014 and 2019.

The Ripple Effect

The Murray cod recovery shows what happens when conservation gets it right. Strict fishing regulations now protect smaller and larger fish, allowing only mid-sized cod (55 to 75 centimeters) to be caught in limited numbers. Fish stocking programs, habitat restoration, and voluntary catch-and-release practices from anglers have all played crucial roles.

More than 90 percent of surveyed fishers now support these conservation efforts. They're not just following rules but actively choosing to release their catches and handle fish carefully to improve survival rates.

The cod's return is healing river ecosystems in unexpected ways. Researcher Stuart Rowland, nicknamed "The Codfather" for his lifetime studying the species, explains that top predators shape entire ecosystems. Where cod thrive, they control invasive carp populations that otherwise explode and damage aquatic plants, leading to toxic algae blooms.

Rivers across Victoria and New South Wales tributaries like the Murrumbidgee and Edward River are seeing similar recoveries. Even the Lindsay River and Mullaroo Creek cod, devastated by fish kills in 2022, have bounced back to pre-2021 levels.

The transformation proves that targeted conservation paired with community support can reverse even severe ecological decline within a single generation.