Jul 082014

Original story by Selina Bryan, ABC News

Scientists at the Tamar Island Wetlands near Launceston are about to wage genetic warfare on a small pest that is causing a lot of trouble.

The mosquito fish, or gambusia, was introduced to Australia more than 100 years ago to fight malaria and was released in the Tamar in the 1990s.

Because the gambusia thrive in calm shallow water and feed off insect larvae, they seemed to be the ideal mosquito control agent.

But being fast breeders and voracious eaters, the mosquito fish, like the cane toads of the mainland, have become the problem.

Now the University of Tasmania is leading a national campaign to eradicate the fish with the support of a $476,000 grant.

The fish has had a devastating impact on native species and Tamar Island Wetlands volunteer John Duggin would be pleased to see them go.

“They’ll eat virtually any live animal, so that includes all the invertebrates, the aquatic invertebrates,” he said

Associate professor John Purser, the director of the National Centre for Marine Conservation and Resource Sustainability, said the gambusia is a prolific breeder.

“It can produce live offspring about 10 times a year, within each batch it could be up to a hundred individuals,” he said.

Traps have been used in the past with some success but scientists are hoping to help the fish breed itself into extinction by tampering with its genetics.

Doctor Jawahar Patil, the lead researcher of the project, said the team would take a Trojan-horse approach to infiltrating the species.

“We call that approach Trojan Y Chromosome approach, which essentially involves breeding Y chromosomes into female populations so that they only produce male offspring,” he said.

Developing embryos will be treated with hormones in the lab and then released into the wild.

The program will be run over four years, with help from volunteers.

“The idea then is that it’ll drive the population to extinction,” Dr Patil said.

If the approach is successful, the researchers hope it will be replicated around the world.

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