Otago Fish & Game officer Ben Sowry and Southland Fish & Game officer Cohen Stewart snorkelled down the river counting fish, while other staff from the two regions walked the banks spotting fish.
Otago Fish & Game officer Paul van Klink said the team counted 107 medium-sized and large rainbow and brown trout on three sections of the river.
Drift-diving gave a good population estimate of what was in in the river at the time — drift-divers typically spot about 60% of the fish in a river — and the information gathered could help to inform management decisions about the fishery.
While the fish numbers were likely not as high as previously seen, there were still enough, but more analysis would be done to compare this year’s findings with the earlier surveys, Mr van Klink said.
The Greenstone is a major spawning tributary of Lake Wakatipu and renowned as a rainbow trout fishery. Many rainbow trout dropped back into the lake after spawning.
‘‘The Greenstone is a really important fishery for international and Kiwi anglers,’’ Mr van Klink said.
‘‘Due to the pandemic and lack of international travel, Kiwi anglers have got this place largely to themselves.
‘‘We are encouraging people who haven’t been to these places to get out and enjoy it, because we have a lot of great fishing on our doorstep.’’
November heralds the opening of several back-country and high-country waterways in the South Island for anglers, attracting about 80,000 a year.
Anglers wanting to fish back-country rivers need a full-season fishing licence and a free back-country licence endorsement.
During February and March, there is also a controlled fishery in the Greenstone with a beat system to manage angler numbers.
