Only 1% are expected to return as adults.
Otago Fish and Game Central Otago field officer Clare Morris said the aim of the project, in its fifth year, was for a yearly salmon run of about 5000 fish returning up the river to spawn.
After being released below the Roxburgh Dam, the smolt swam to the ocean, where they matured into adult fish.
At present, about 300-400 salmon made the return run.
Ms Morris said that last year, the first returning fish from the programme were recorded. They were evidence the process worked, she said.
Anglers had been surveyed in an effort to estimate the number of fish caught below the dam, which was as far up the river as they could swim.
During the last salmon run, between about November and April, 74 anglers were interviewed and a total of 87 fish catches were recorded.
Fishers were also asked to return the heads of salmon they caught to Fish and Game so the ear bones, otoliths, could be collected.
Analysing these could provide information about migration of salmon and what they had been eating.
Fish head returns and angler surveys would be conducted again this season, with prizes available as incentives for anglers to take part.
Smolt for the programme, funded by Contact Energy and Fish and Game, came from a hatchery in Canterbury and were released in June.
The programme did not have a definite end date, and would continue until the returning fish target was met.leith.huffadine@odt.co.nz
