Conservation group WWF Australia says anglers are catching significantly bigger barramundi in parts of Queensland where commercial net fishing was banned in 2015.

The Queensland government introduced net-free zones off Cairns, Mackay and Rockhampton in November 2015, closing them to all commercial net fishing.

The ban included the use of gillnets, which trap fish by suspending large rectangular mesh nets vertically in the water.

A WWF-commissioned report by University of Queensland researchers, who included the state’s former chief scientist Hugh Possingham, compared fish tagging data from citizen science database Infofish Australia six years before and six years after the ban.

It found average tagged barramundi sizes increased by about 23 per cent in Rockhampton [from 50.7cm to 62.3cm], 21 per cent in Cairns [from 50.5cm to 60.9cm] and 13 per cent in Mackay [from 50.3cm to 56.9cm].

WWF spokesman Richard Leck said it used to be rare for recreational fishers to hook a metre-long barramundi in central Queensland.

“Now it’s almost a weekly occurrence that they’re pulling barra out of the Fitzroy (River) that are 1.2, 1.3 metres,” he said.

“The bigger those fish are getting on average the more offspring they’re having and the healthier the ecosystem becomes.”

The report also found “trophy-sized” king threadfin [of more than 1 metre] caught in the Fitzroy River went from 2 per cent of catches before the ban to 63 per cent after the ban.

Long-time recreational fisherman Dan Hammersley said it was a similar story in Cairns.

“I have noticed an increase in numbers as well as sizes of many species of salmon, barramundi, fingermark, also grunter and other lesser known species,” he said.

“I do know there are a lot of barra now getting caught around the 90cm to metre mark, especially around the Cairns Inlet and some of the beaches.

“It’s definitely been a success for recreational fishing.”

WWF calls for wider gillnet ban

Commercial fishing extracts about 8,000 tonnes of seafood from the Great Barrier Reef Marine Park each year.

WWF said net fishing was declining in productivity but also posing problems for marine animals such as dugongs and turtles that became entangled in the nets.

Mr Leck said the practice was allowed in more than 60 per cent of the marine park and should be phased out throughout in line with UNESCO recommendations.

“As we understand there’s probably about 70 or 80 active commercial gillnet fishers in the reef’s waters at the moment,” he said.

He said extending the ban would benefit the environment, recreational fishing and tourism, and affected commercial fishermen should get fair compensation.

Mr Leck said alternative methods such as line fishing and fish farming could provide seafood to consumers in a more sustainable way.

“A lot of those target species, particularly barramundi, increasingly are moving towards being produced by aquaculture,” he said.

‘Selfish’ push for farmed fish

Queensland Seafood Industry Association president Allan Bobberman said WWF’s report was not definitive proof the net-free zones were in better shape ecologically.

“I have sat in working groups with the harvest strategy with the Queensland government and I’ve had delegates there from the Mackay region complaining about depletion of stocks, so what really is the story,” he said.

He accused WWF of being “selfish” for expecting consumers to eat more farmed or imported fish over Australian wild-caught.

Mr Bobberman, a mackerel fisherman who also holds the only commercial gillnet licence in Cardwell, said a net ban throughout the Great Barrier Reef would be devastating for many such as himself.

“Just buy my licence and kick me to the kerb? I’m nearly 70 years old. What am I going to do? What happens to all my boats and infrastructure, who’s going to buy it,” he said.

“There’s not too many fisheries now that you can just move across into.”

He said the other fisheries were at full capacity.

“So to say ‘oh well you’ll be right, we’ll just shut you down, you can move into something else’, it’s not that simple,” he said.

“The ocean is a resource to feed the people … I think there’s a lot of other factors out there killing some of them cuddly creatures other than commercial fisherman’s efforts.”