About 400 juvenile brown trout will be released into the Avon River on Wednesday as Fish & Game attempts to encourage them to return to the river to spawn.
The trout have been donated by Tony and Rosalie O'Neill of Christchurch, who will release them into the river which runs through their property in Fendalton.
North Canterbury Fish & Game says trout numbers in the Avon have been in decline for the past 15 - 20 years.
General manager Rod Cullinane says they hope to see the first of the 400 yearling 'browns' return as adults to spawn by early next year.
Last month, 800 trout were released into the Wairarapa Stream in Christchurch.