A fish named Gollum took centre stage at the Nevis River hearings yesterday.
The Nevis contained a unique population of galaxiid fish, freshwater ecologist Richard Allibone told a special tribunal appointed to consider an amendment to the water conservation order on the river.
The fish - Gollum galaxias - was the only native fish species in the Nevis.
Asked by tribunal member Rauru Kirikiri about the name of the fish, Dr Allibone said it was a small, dark, big-eyed creature.
"It's an appropriate name."
The existing water conservation order did not recognise this native fishery value.
The fish were classified as a threatened species and the Nevis population was an outstanding one, because of its unique characteristics, he said.
Tribunal chairman Richard Fowler asked if it was a species that had been "frozen in time" and Dr Allibone said it was a very old species.
A hydro development in the Nevis would inundate the galaxiid's habitat, Dr Allibone said.
A prohibition on damming would reduce the risk of one of the main predators of the fish becoming established.
Six threatened plants, including three "acutely threatened" plants, were growing in the Nevis valley.
"The lower Nevis valley retains some of the least modified areas of critically endangered environments in New Zealand," he said.
