It is the first time in the world that giant freshwater crayfish have been released after being hatched and reared in captivity.

The juvenile crayfish are 10 times bigger than when they first hatched - increasing their chances of survival.

In a partnership between Huon Aquaculture and Todd Walsh, a Tasmanian ecologist and conservationist, the crayfish were raised and released under a program that aims to boost numbers in the wild. A threatened species, giant freshwater crayfish have long lifespans and are slow growing.

They are also only found in very specific areas, in rivers below 400 metres above sea level in Northern Tasmania.

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The Tasmanian giant freshwater crayfish is the largest freshwater invertebrate and the largest freshwater crayfish species in the world.

It is also under threat due to predation, poaching, sedimentation and habitat loss.

Huon aquaculture general manager David Mitchell said the program was established to help with reintroducing the crayfish into areas where the species may have been extinct for generations.

"Huon became involved in the project as a way to help conserve the species, which is present in the waterways near our hatchery," Mr Mitchell said.

"Our team has been there at every step of the way alongside Todd so today's release is the culmination of years of work and patience.

"Today is a significant step forward for the species, particularly for the North-Eastern Tasmanian population."

The juveniles were tagged and measured before their release and will be monitored by Mr Walsh in coming years.