Fish picked to keep lake anglers happy

SELECTION: Fish & Game officer Lloyd Gledhill selects a female rainbow trout to sedate before "stripping" her eggs. PHOTO/SUPPLIED

It is spawning time on the Rotorua lakes, with Fish & Game staff trapping the biggest and best trout for its Big Fish Breeding Programme.

The hand-picked specimens are the breeding stock used to raise more than 100,000 fish to keep North Island lakes stocked up for anglers.

The fish are trapped as they swim upstream to spawn - in a stream that flows into Lake Tarawera, known for its hard-fighting trophy trout.

They are carted off to holding pens in a stream that flows through Fish & Game's Ngongotaha hatchery grounds.

A set of selection criteria is used to pick only the best fish as parents - a female to supply the eggs and "cross" with a male used to fertilise them.

The aim is to produce fish which are healthy and grow rapidly to a large size for anglers to catch.

This year the largest fish appear to be around the 65-68cm mark, so fish over 62cm fit the selection category for the moment.

"Later in the season we might change the selection size, depending on how the run is going," said Fish & Game officer Lloyd Gledhill.

"You never quite know how many fish might come in, and once they have been through the trap it's too late to get more. "If we don't get eggs now, there will be no fish to release next year so the pressure in on."

Fish & Game aims to end up with 135,000 viable fish, which means stripping an estimated 250,000 eggs from "ripe" hens.

Every spawning season they "cross" about 180 fish in total.