Page 26 - fish_farms_curriculum

Picture 10. Network system harvest

In 1987, one of the largest and most successful freshwater fish hatcheries was established on

the North Island of New Zealand. A fish farm was established on this island to take advantage
of the geothermal waste heat in the Wairakei power plant area.

Picture 12. Catfish

There are nine pools in the fish farm with sizes ranging from 0.2 ha to 0.35 ha and depths

ranging from 1.0 m to 1.2 m. The water in the pools is kept at a temperature of 24°C and the

temperature changes only 1°C as you go from one end of the pools to the other. The fish farm
can produce shrimp up to 30 tons per year. Adult shrimps are harvested in about 9 months and

30 or 40 of them weigh 1 kg. An additional aquaculture farm will be built on the other side of

the Wairakei power plant in the near future. Waste cooling water of a second power plant to
be built in this fish farm will be used and thus 400 tons of annual production will be provided

from these farms. Experiences at the Oregon Institute of Technology has shown that the best
ponds for shrimp, mosquito fish and trout are those with a surface area of 0.1 ha. The most

important issue to be addressed is water quality and diseases. If geothermal water is to be used
directly, substances such as fluoride, chloride and arsenic must be investigated to determine

whether fish or shrimp can survive in geothermal water.

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