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Market size Packed for sale Koura in berry Intake fish trap Hatchlings settling out done to check on the water quality. To our surprise, the eggs hatched in two months, a full three months ahead of eggs kept in ambient water temperature. A full-size hatchery had to be built in the following year, but in what? Unfortunately in 2008 we lost all our salmon due to stock pollution of our water supply, which had been an ongoing problem for some years. Thankfully the council did something, though they left it a bit late, and the pollution did not effect the koura. This left us nearly bankrupt but with a lot of surplus ponds and gear. One of our salmon hatching troughs was fully insulated and installed in our disused processing shed. An insulated bulk fi sh bin was installed in the roof for a head tank, and a collection tank installed under the salmon trough with a submersible pump on a fl oat switch to collect the water and recycle it back to the head tank. I would like to thank Brent Pickering for his input into the technical details of recirculating systems. The whole system is gas-heated on a thermostat, which also adds fresh water several times a day. We now start the indoor hatchery at the beginning of July and have the hatchlings out in in the races at the beginning of September. When the fry start leaving the females we collect them every four days and bulk weigh them on micro-scales to obtain the numbers by average weight. These are then stocked at 50 per m2 in the one-year races. The survival rate is 97 percent to stocking out. We now also keep male and female broodstock separate in our disused salmon ponds. A result of selectively breeding fi sh is the different colour variations that come through. As black or olive green is not a very good marketing point we decided to work on this. About six years ago I got a real surprise one day while grading a yearling race to see fi ve bright red fi sh about 50mm in length. I treated these like royalty but, as Murphy's Law would have it, I lost all fi ve one way or another and thought, that was that. Two years later, 32 more appeared again. I kept these separate until they reached breeding size. Last year I bred Incubator box these back across each other and had one small female get in berry. She was kept aside to hatch out her eggs undisturbed. As a result, last spring all her offspring were red. I still don't know which fi sh will produce red offspring from standard- coloured fi sh, but I know I have produced fi sh with a red gene. Last year I had 60 red fi sh from standard-coloured fi sh and now I have 200 red fi sh and 16 large red females in the hatchery. I am hoping for all red offspring, but three percent of red juveniles revert back to brown. As far as I know we have the only fully red freshwater crayfi sh in the world. These fi sh really turn heads in the marketing sector and could easily compete with scampi and the like. I guarantee the photographs published with this article are the real thing, the koura are not colour- fed and there have been no genetic experiments. The red colour is natural, like any other farmer would do to get a particular trait. We hope to have commercial numbers in a few years. The farm is producing two tonnes/ha equivalent, with a gross return of $55,000 to $60,000 per tonne, plus freight and so on. Running costs vary, depending on how much artifi cial food is used. I developed a special diet and it is fed as a supplementary ration to boost their natural diet. Predators were a big problem at the start, with numerous races of koura lost to eels. It took several prototypes before I came up with what you see in the photograph. This still allows us to use an up-stand to control water depth, but also incorporates a trap for fi sh and to draw stale water from the bottom of the race. We use 3mm slots on the grow-out races and 1mm slots on the hatchling races to stop the hatchlings from migrating out. The screens seldom become blocked and the screened and horizontal sections can be removed to let frog weed fl ow out without lowering the water level. Work needs to be done on identifying the gene for fast growth and the production of single-sex specimens to speed up growth rates. Just remember, all you would-be aquaculture folks out there. Don't believe what you hear until you try it. NOVEMBER/DECEMBER 2011 ■ NZ AQUACULTURE ■ 7