A NEW project is underway from the Department of Fisheries to save Western Australia’s freshwater native fish and ultimately protect our human population from the spread of disease.

Department of Fisheries scientist and project leader Dr Craig Lawrence says the launch of the project has been nearly 10 years in the making.

A Western Australian Gilgie / Image: Istockphoto

“We now have all the pieces of the puzzle and can put them into action,” Dr Lawrence says.

The 12-month project, to be completed in December, aims to restock the “fragmented” populations of native fish.

“This means all the water bodies used to have these fish and now gradually they are not in certain places. They’re not extinct, they’re just not where they used to be found,” Dr Lawrence says.

The Worldwide Fund for Nature ranked the South-West of WA as one of the 53 most “biologically outstanding hotspots” in the world because 100 percent of the area’s native crustaceans and 80 percent of the native fish are found nowhere else on Earth*.

However, in recent years, freshwater habitats have been destroyed by rising salinity, agricultural run-off, draining of waterways, pollution and changing weather patterns.

As a result, the State’s human population risks growing exposure to disease because these native fish control mosquitoes and therefore mosquito-borne illnesses such as Ross River virus.

Dr Lawrence says projection models created from previous work also show if we experience rising temperatures from climate change, then the State risks the spread of tropical diseases such as dengue fever and malaria.

“My concern is tropical diseases, that we’re not use to living with, could become a serious health issue if we don’t start dealing with these fragmented populations in our water bodies,” he says.

“So we have to make sure our water bodies are stocked with these native fish.

“That’s the big picture but what we have to do in the next 12 months is get a baseline by surveying a region of 700,000 square kilometres which will allow us to prioritise conservation and rehabilitation for water bodies at greatest risk.”

The baseline survey will database the genetics and distribution of native fish in every wetland from Geraldton to Busselton and east to Northam.

“In the past six years we’ve been working out how to develop large-scale production techniques of native fish,” Dr Lawrence says.

However, he says re-stocking native fish is a complex process.

In some instances, in order to restock, people have taken fish from a water body and just placed them in another.

“They think it’s the right thing to do but the problem is the fish can carry disease from one water body to another one and there is an issue with moving a genetic line from one to another, causing problems,” he says.

“We identify what genetic line needs restocking and stock the right fish so we don’t create in-bred populations.”

Dr Lawrence’s team, comprising Neil Rutherford and Rod Hamilton as well as students from the University of Western Australia, have already successful bred pygmy perch and are now working on western trout minnow.

* Anderson, C. “Desperately seeking native fish”. Pp 44 - 47  Western Fisheries. December 2009.

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