By Joe Hinchliffe

Every year in late December when Michal Duzynski was a boy his family would put a live carp in the bathtub.

A few days later, the fish would be the main course on Christmas Eve.

The Polish traditions with carp at Christmas don’t end there.

“If you put the largest bone or scale in your wallet and you don’t lose it, you don’t lose your money,” Mr Duzynski said.

These days, he is a world away, living in South East Queensland. But carp is still a big part of his life.

Today, Mr Duzynski has one of the best fly fishing casts in the world.

And every weekend, he goes fishing in the Scenic Rim. He only chases carp.

Most Saturdays see him up at 4am to catch first light at Wyaralong Dam. He walks the banks, stalking his quarry. He has learnt to read the water, to see fish where others only see ripples. And he casts so that his fly hits just the right spot, a few metres in front of where the fish is swimming.

In a matter of hours, Mr Duzynski might catch 10 fat and healthy carp.

But if he were to try to take one home to his bathtub in Brisbane, he would stand to lose money. A hell of a lot of money.

Mr Duzynski has seen signs warning of maximum penalties for possessing carp of $220,000.

“I wouldn’t mind trying a nice big Aussie carp,” he said.

“But nearly a quarter of a million dollars is definitely not with it.

“I’d be paying for that one fish my whole life.”

Which is exactly how fishing regulators in Queensland want anglers like Mr Duzynski to feel about fish like carp.

Rod Cheetham runs Fisheries, Aquaculture and Wildlife Developments.

“One of the things I want people to do is to hate them,” Mr Cheetham said of pest fish.

The former fisheries officer and a fisherman is on a mission to keep another noxious fish out of the Murray Darling Basin.

Like carp, tilapia is considered superb eating fish in many parts of the world. And, like carp, it has infested much of South East Queensland.

But it has not yet reached the country’s longest river system.

Mr Cheetham shudders to think of what would happen if tilapia turned up in the Murray.

“You’d just be putting yet another nail in an already seemingly prepared coffin,” he said.

It is a similar story for carp. While much of the South East is overrun with them, there are still “an awful lot of Queensland waterways” that are carp free.

Both species are prolific breeders and eradicating them from where they are present may never be possible. That is why preventing their spread is paramount, Mr Cheetham said.

Which means recreational anglers targeting pest species is something of a double-edged sword.

In general, it is a good thing for the community, Mr Cheetham said. But there is one major caveat.

“Where you run into problems is once the fish becomes valuable,” he said.

Because managing pest fish in our waterways is not just about ecology. It is also about human nature.

In NSW, where carp are almost ubiquitous, they are harvested to make fertilizer. There, unlike in Queensland, authorities do not ban returning caught carp to the water. Instead they encourage anglers to kill them and “utilise any captured carp”.

Mr Cheetham worries a similar policy north of the Tweed could facilitate the invasion of pests, both through unintentional spreading of their eggs, and worse.

“Because human beings are what we are, [some people might think] ‘gee whizz, if these fish are here, and I am doing well and making a living out of it, what about if I move them to this river which is a little bit closer to where I live?’,” he said.

Principal research fellow with the Australian Rivers Institute, Mark Kennard, also strongly supports Queensland’s zero tolerance approach towards noxious fish.

But, like Mr Cheetham, he also supports recreational fishermen targeting them, provided they are killed and either buried or binned.

This month the annual Wyaralong Dam Carp and Tilapia Eradication Competition would normally have been run.

Though it was postponed due to Covid-19, organisers are promising to come back bigger than ever in November 2021.

In addition to removing pest fish from the dam, money raised by the competition is invested in stocking native fingerlings.

Mr Kennard said that such events alone will never eradicate tilapia and carp.

“But they do increase community awareness around broader issues of invasive species and the health of our waterways,” the Griffith University academic said.

“So while, in and of themselves, they are ineffective, they can be an important component of a broader strategy.”

On one hand, they help demonstrate why healthy waterways matter. Whereas many natives need submerged logs in which to breed and plants to clean the water, the invaders can thrive in the most degraded of rivers.

But also, he said carp and tilapia busting events were “really valuable” in getting the general public to treasure the “national heritage” that is our indigenous freshwater fish.

In the South East, he points to the Mary River Cod, Australian Lungfish, Ornate Rainbowfish and Honey Blue-eye as examples.

“We have an amazing diversity of fish found nowhere else in world,” he said.

And there is anecdotal evidence, at least, that this approach is having some wins.

Jason Terelinck and Nicole Whysall run the Facebook page Pest Fishing Adventures.

They say they are part of a growing community of anglers targeting pests.

Whereas Mr Duzynski uses specialist gear, Mr Terelinck and Ms Whysall use worms. They are no less successful than the fly fisherman.

“You could use a kid’s line if you want,” Mr Terelinck said.

“It’s the easiest fishing you can do.”

And it’s “highly addictive”. Before Covid hit, the Ipswich couple were fishing six days a week.

A lifelong fisherman, Mr Terelinck said their adventures with pest fish began a few years ago at Boonah’s Teviot Brook.

“The amount of tilapia was incredible,” he said.

“We could pull in a bucket of fish in a couple of hours. It snowballed from there”.

They joined the Logan and Albert Fish Management Association and take part in its carp and tilapia busting competition at Wyaralong.

But it hasn’t just changed the way Mr Terelinck fishes. He also keeps fish in home aquariums.

For 20 years, it was cichlids, the family of fish to which tilapia belong. Not anymore.

“I’ve swapped them all over to natives now,” he said.

“Lungfish, barramundi, jack, saratoga all the way down to rainbow fish and gudgeons.

“They’re just really nice fish.”