Hatching & Releasing Trout Rotorua New Zealand
Rearing Rainbow and Brown Trout at the Ngongotaha Trout Hatchery
Mar 10, 2009
During the autumn-winter months Eastern Fish & Game officers select and withdraw adult trout from traps set at Lake Tarawera. Only big, well-conditioned adults are chosen. Their progeny will subsequently be released into Rotorua lakes and other locations throughout the North Island.
For Future Trout Fishing in New Zealand Fertilised Ova are Transferred into Specially Constructed Incubators
After being transported to the Ngongotaha Hatchery on Paradise Valley Road, Rotorua, the hens (female trout) are stripped of their ova. The ova are then fertilised with milt from a male and the zygotes transferred into especially constructed incubators fed by free-flowing spring water with a consistent temperature of 11ºC . Hatchery staff are trained to ensure adult brood fish suffer minimal stress and after a brief holding period, they are returned to the wild.
When the Young Alevins Emerge the Trout Fry Swim to the Surface
The ova are carefully monitored until hatching some 28 days later when the alevins emerge. After a further 18 days tiny trout fry swim to the water’s surface in search of food. A sprinkle on the surface is all that’s required, but it must be given hourly at this crucial stage of the fish's development. Scrupulous attention is paid to filtering and cleaning the water, with hatchery staff using a gentle vacuum system to suck up the waste from the bottom of the tanks.
Over the following months the feed is increased proportionately, although feeding times are reduced until the fry are about six months old. While most of the trout are rainbows, browns also feature prominently and there are also the interestingly-patterned tiger trout which are the result of inter-breeding, and albinos or blue trout which stand out among their darker counterparts.
Trout are Transferred from the Hatchery Building into Rearing Ponds
At six months old, the trout are transferred from the hatchery building into open “rearing ponds” where they continue to grow until large enough to be liberated about 12 months after the hatch. Because of the large numbers of fish kept in the ponds, they still need to be fed by hatchery staff, but they also learn to capture their own food during this time.
Useful Statistics are Provided when Trout Appear in Eastern Fish & Game Traps
Prior to release each trout is clipped according to its year and season of liberation. Clipping is carried out with the aid of a mild anaesthetic to calm the fish while it’s handled. Should the trout turn up again in an angler’s catch, or in an Eastern Fish and Game trap, the clipped fins help to identify its age and year of release, providing useful statistics for the management of trout fisheries.
After clipping the trout are released into a chute from which they swim into the “Trout Transporter” truck and are liberated into designated waters. Hatchery officer Mark Sherburn says that the survival rate from spawn to release is very high when compared with natural spawning.
Kids can Catch Trout at Ngongotaha Trout Hatchery
Several times annually the Hatchery holds “Kids Fishing Days” where youngsters can experience fly fishing, assisted by either hatchery staff or members of the Rotorua Anglers Association. These popular events give young people the opportunity to practice a healthy, sustainable sport that not only offers a lifetime of enjoyment, but also allows the angler to put food on the family table.
The Ngongotaha Trout Hatchery, 1130 Paradise Valley Road, Rotorua, New Zealand, is open to the public from 9:00am to 4:30pm daily (except Christmas Day and Good Friday). Trout can be observed both in their natural environment and in the rearing and holding ponds. The hatchery is approximately 20 minutes north of Rotorua city. Entry is free for the casual visitor. For guided or group tours, or for any other information, contact the Eastern Fish & Game office 64 7 357 5501 or by email info@erfgc.co.nz.
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