Thousands of young trout have been clipped before their release into Lake Rerewhakaaitu this week.

Eastern Region Fish and Game officers braved chilly spring waters to clip the trout.

Fish & Game Officers fin clip thousands of young sedated trout before their release.

'The trout are sedated before one or more of their fins are painlessly snipped off to identify what year they were released,” says officer Mark Sherburn.

'The yearlings pack on weight quickly once released into lakes to be caught by anglers as hefty fish weighing 2kg or more in around 12 to 18 months.”

He says this week's release was the last autumn 'liberations” into most of the Rotorua lakes – bringing the total number of fish release to about 29,000.

The hatchery releases more than 100,000 trout annually around the North Island, from Northland to Wellington.

Mark says the hatchery's aim is to manage sustainable fish stocks to lift angler rates.

'What the hatchery does is supplement the wild populations so anglers have plenty of quality fish to catch.”