''It's really alarming, finger-in-the-dyke stuff.''

The main threat to the fish in the past 10 years had been trout, he said.

''There's no debate about that. We've just got to find how to stop it.''

He was quick to point out Doc was not anti-trout. In fact, under the Conservation Act, it had to protect them.

It was about protecting the populations of galaxiids left and as their preferred habitats were not in the major trout-fishing rivers, fishermen should rest easy, he said.

''There is room for galaxiids, farmers and trout. We just all have to be flexible.''

Other factors were involved in their demise, including water quality and quantity, gravel extraction and willow removal.