Tasmania's fight to bring back the giant freshwater crayfish

Giant crustaceans who hide in the banks of rivers, and roam across the land when no one is looking.

Once, giant freshwater crayfish were easy to find. But after years of overfishing, habitat loss and and flood events, many Tasmanians have even forgotten their existence.

Fiona Marshall spends a lot of time knee deep in rivers, leaving her perfectly qualified to coordinate a project focused on recovering the iconic creatures found no where else in the world.

"Like so many ... I'm scared of losing them. I want my children to see them, and my children's children," she said.

"They live for about 60 years. The females don't reach sexual maturity until they are about 13.

"You take a few of the big ones and you literally set the things back decades.

"My job is to increase awareness, and give landowners simple actions they can take to help them thrive."

The project - funded by the federal government and run through the Cradle Coast Authority - started in October last year, and Mrs Marshall said she had been speaking with landowners since February.

One of the difficulties, she admits, is that part of her job is asking farmers to plant out prime agricultural land with trees and scrub.

"It gets a mixed reaction," she said.

"It's about getting the balance. When you clear your land right to the edge of the river it ends up falling in.

"I'm a farmer myself, I understand where farmers' priorities lie."

The project is in early stages, and Mrs Marshall said the team was still mapping the areas they would target.

"We want to get the key populations, and also areas where we don't have to change the whole landscape, but can do little things to change it," she said.

"It might just be lacking deep-rooted trees, or scrub and shady areas, or needs grass nearby to keep the mud out of the water."

She said she had not seen many, even though her job involved keeping track of them.

"The old farmers, they remember them. They've seen them walking right across gravel driveways."

Todd Walsh has been monitoring Giant Freshwater Crayfish across the region for decades and enlisted to help with the project.

"All you need ... is somewhere to hide when they're young, somewhere to shade to keep them cool, a food source and clean water coming through ... It's not rocket science," he said.

"Where there's nothing ... these guys die out pretty quick."

A similar project is also being undertaken in the Tasmania's North-East.

Fishing for Giant Freshwater Crayfish is illegal and can incur fines of up to $10,000.

An explainer video can be viewed on the CCA website.