If not for the dogged determination of a couple of sharp-eyed canoeists and then a raft of agencies and scientists, a much-loved turtle found only in a single river of northern NSW would be no more.

In early 2015, Rowan Simon and a friend were canoeing on the Bellinger River about 10 kilometres up stream from Bellingen when they spotted a snapping turtle on a rock. Surprisingly, it didn't move as they paddled up.

Back from the brink? Ten Bellinger River snapping turtles were recently released back to the wild. Credit:Paul Fahy/OEH

"It was weird - just sitting there," the "Bellingen born and bred" local said on Wednesday.

Closer inspection showed "its eyes were grown over with this disease", Mr Simon said, adding they found another ailing animal 20 minutes upstream.