Giant Goldfish Threatens Australian River Life

Invasive fish has been found in WA rivers

Aussies have been warned to think twice before flushing goldie down the loo or releasing them into the local river systems after the discovery of giant goldfish in the rivers of Western Australia, weighing more than 2kg.

Scientists believe that the giant species, which is not native to Australia have even adapted to saltwater and now have the ability to move between rivers and into estuaries. Dr. James Tweedley from the Centre of Fish and Fisheries Research at Murdoch University in Perth explained:

"This research indicates goldfish could start using estuaries as a 'salt bridge' to invade and colonise new rivers. Clearly, the fish are capable of tolerating saline conditions for several months,"

"They are a known vector for the introduction of parasites and diseases, so this is bad news for native fish species and the overall health of our precious water systems. It is important unwanted goldfish are returned to reputable aquariums rather than released into rivers."

The average goldfish is native to eastern Asia, but the species is popular all over the world. The goldfish is a particularly invasive species as they eat vegetation and release harmful nutrients into the waterways.

Once these small fish are released into water systems, they become particularly difficult to get rid of.

The bulk of Dr. Tweedley’s study surveyed 526 individual fish in the Vasse and Wonnerup estuaries near Busselton in WA.

The discovery of these mega fish was made last August, but smaller species have been caught in the Lower Vasse River since 2003.

The species generally travels hundreds of kilometres annually in Western Australia’s waterways. They taint water quality, introduce harmful diseases to native ecosystems and disturb our native species.

Dr. Stephen Beatty from the centre for Fish and Fisheries research explains:

“Once established, self-sustaining populations of alien freshwater fish often thrive and can spread into new regions. This is having a fundamental ecological impact and are major drivers of the decline of aquatic fauna."

Western Australia, think again before flushing your pet fish down the toilet.

Lead Image: Vasse goldfish, S.Beaty

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