In a role similar to a superhero, a Brisbane man is taking the future of Moreton Bay's eco-system into his own hands by watching over local crustacean habitats.

'Crabman' aka Gavin, chooses not to use his last name in an effort to remain anonymous.

He uses social media to track and report illegal crabbing behaviour and to also educate fisherman on the harm that removing undersized crabs will have on south-east Queensland waters.

After starting a Facebook page Crab Watch Queensland less than a year ago, the group has more than 9,000 followers and features videos and photos of offenders in action.

"Every week we go down to the local jetty and we see that people are taking undersized crabs in large numbers," said Gavin.

"It started when the local kids in my area kept seeing problems and they reported it, and I would record it but fisheries were [too] understaffed to send someone out.

"We would report it but then we started taking the information ourselves."

Unidentified crab pots and illegal-sized crabs are problems the Crab Watch Queensland team is tracking. ( 612 ABC Brisbane: Jessica Hinchliffe )

Gavin says the group does not try to stop illegal crabbers or touch their catch, but simply takes information.

"I am a general fisherman and I want to see what people are catching and I ask them what they are catching," he said.

"Half the time they show me their crabs and if they are undersized, they usually put them back in the water after they have realised it."

The future of eco-systems

Gavin hopes through his work as 'Crabman' people will learn more about the local environment and eco-system.

Mud crabs are one of the crustaceans the group often sees undersized. ( Supplied: Crab Watch Queensland. )

"I think people need to look past their cooking pot, they need to realise that this is not just a feed ... it will affect the eco-system if we do not do something about it," he said.

"It really is a problem throughout Australia, an example of this was a few years ago with Sydney Rock Oysters, there are none anymore.

"People were poaching them and now Sydney Harbour is having a massive silt problem because these oysters were breaking down the sediment in the water."

He hopes that the group will make a difference before it is too late.

"If we do not stomp this out it will get to the stage where there are no crabs left," he said.

"I think there are some people who are misguided or uneducated, but these people buy their pots and bait, why can they not buy a crab measurer or get information from the internet?"

Fisherman heading out early on the water at Wellington Point, Queensland. ( 612 ABC Brisbane: Jessica Hinchliffe )

Reporting activity to the authorities

Diagrams available online and in fishing stores show the correct sizing for Queensland mud crabs. ( Supplied: Fisheries Queensland )

The group films suspected offenders, takes their number plate details and passes the details onto Fisheries Queensland.

Gavin says the group knows its role in the community.

"People getting involved in this can jeopardise the investigation with fisheries, so you really need to stand clear and take as much information as you can without getting in front of them," he said.

"Usually 99 per cent of the time people feel guilty as they are caught doing the wrong thing so I do not cop too much flack."

In a statement sent to the ABC, Fisheries Queensland advises Crab Watch Queensland to report all suspected illegal crabbing to the Fishwatch hotline and urges the general public to also report any illegal fishing incidents to 1800 017 116.