Young salmon encouraged to linger for longer in fenced off waterway

It's been 70 years since fresh mountain water rippled through the east branch of Glenariffe Stream in Canterbury's Rakaia Gorge.

Now, thanks to a generous bequest, it will soon flow again.

The stream used to wind across flats on Glenariffe Station, which is owned by Mark and Belinda Ensor.

Years ago it was diverted into the main stream by Mark's grandfather so he could turn a large wetland area into farming land.

"When [my grandfather] was running the farm, he only had about 30 hectares of paddocks so it was an economic reality of having to develop things."

Glenariffe Stream is one of the key fish-spawning streams in the Rakaia catchment, says High Country Wetland & Waterway Protection Project manager Steve Terry.

As a local Fish and Game officer, he's spent many years doing aerial fish counts and salmon-spawning surveys.

"I kept looking at what we could do to enhance the fishery in terms of keeping the salmon in these headwaters.

"We want the little fish to remain here in these wetland environments for as long as possible. If they're not a fingerling size they can't survive in the ocean."

Thanks in part to a large bequest, Fish & Game have managed to purchase from the Ensors a 44-hectare block of land that the stream goes through.

Part of the money will go towards re-diverting water back into the east branch where it once flowed, Steve says.

"The goal now is to naturalise the stream so this becomes a much bigger wetland and we're putting a QE2 covenant over it.

"All the little backwaters and swampy bits are are where the juvenile fish tend to want to live, so we're creating a habitat for them."

Corridors of land are being been fenced off to stop cattle from entering the streams and disturbing silt, he says.

"Adult salmon can spawn in any gravel area but they don't like silt because it fills in the cavities in the gravel where they lay the eggs, and often causes a fungus to grow on the eggs and then they don't hatch."

After several months without grazing, wetland plants are already starting to reappear and spread.

From a farming point of view, selling the block is a good outcome for Mark and his wife Belinda.

"The land definitely wants to do its own thing here," Belinda says. "No matter what we're doing on top of it, it's always going to revert or try its best to, in this case, be a wetland."

"I've always said that if they come up with enough money we can do a deal," Mark adds.

"We all knew that it would be good for the environment and the salmon."