Next we're learning about carp which are one of Australia's most destructive pests in the water. But recently scientists announced that they've found a way to control them. They've found a virus that they think should get rid of most of them. But is releasing a new virus a safe way to fix the problem? Matt found out.
They're the outlaws of our lakes and rivers, wanted for damaging our waterways and harming native plants and animals. Carp are a real menace. And no-one has managed to stop them until now.
Carp were first introduced to Australia in the 1800s for food and sport. Today, there are millions and millions of them, and they've spread in lakes and rivers in south eastern Australia.
MATT HOLBROOK, REPORTER: So even if I did manage to catch one or a lot more, it's probably not going to make much of a dent in the overall population. Oh well.
One of the big problems is that carp take up important space and resources that native fish need. They collect food by sifting through mud which, well, muddies everything up.
They can also survive in tough conditions and breed really quickly. A single female can produce up to 1.5 million eggs. And they're just some of the reasons carp are on our "Wanted" list. But now scientists at the CSIRO reckon they've found a way to deal with them. A virus that kills carp, and leaves other plants and animals unharmed.
DR KENNETH MCCOLL, CSIRO: We can show that this virus will only affect carp and carp alone. What this virus does is to injure the kidney and skin of carp and so they, the affected carp, then take on water and they effectively drown.
Carp aren't the first introduced species in Australia to be targeted in this way. In 1950 scientists used a special virus called myxomatosis to try to control the rabbit population. Hundreds of millions of feral rabbits had spread across the country, eating crops and natural vegetation, and myxomatosis was seen as the answer.
It quickly wiped out most of the species, but some were resistant. So in 1995, a different virus was used, the calicivirus. They both helped reduce rabbit populations in a big way, but didn't get rid of them completely.
Other attempts to control pests have been a lot less successful. Cane toads were brought in to Queensland from South America to eat beetles that were annoying sugar cane farmers. Soon they got a little too comfortable and started spreading everywhere. To top things off they're poisonous, so they make our native animals sick if they try to eat them. That one was a real fail, so people are always cautious about the unintentional impacts of releasing a new animal or disease.
But scientists say that after years of testing, the virus is safe for all other animals, and is the best way to deal with the carp problem. That's why recreational fishers and conservationists have teamed up to support the plan. It still has to be approved by the government, and that process could take a couple of years. But it means this wanted, or rather, unwanted pest, could one day be gone for good. And until then, I'll do my bit to help!
