What do koura eat

The two species are separated by the Southern Alps. They can run very fast forwards and swim backwards by flicking their tails. Koura live in lots of different types of freshwater environments. They are found in streams, rivers, ponds, lakes and wetlands in native forest, exotic forest and pastoral waterways. In some wetlands, during the dry summer months when water levels get very low, koura can burrow deep into the mud and then come out again when the water returns. The blame lies squarely with our failure to care for their habitat.

No-one knows more about this than John Hollows. He is a scientist and conservationist who has studied the impact of changing land use on our native crayfish. His conclusion? John believes the global demand for freshwater crayfish can support a profitable niche industry and this will save the species. Everything he knows is in a recently-released, how-to guide that he hopes will encourage more people to do so. This is a business initiated by forestry company Ernslaw One to gain additional revenue from the hundreds of fire ponds in its forests.

Normally, they are only used in the event of a fire. The business is commercially savvy, using existing infrastructure, but also award-winning. Some ponds are now in varying degrees of readiness. Stocking a pond takes time, which means it will be years before the company can guarantee a steady supply, let alone make a profit. Last year John harvested just kg for sale. John Hollows checking crayfish in a live capture fyke net. This book is a document a lay-person can understand.

John emptying a fyke net to check on the crayfish; a South Island crayfish ready for sale will weigh about g. These are all smaller in scale than Keewai, and semi-intensive in the use of supplementary feed and mechanical aeration of water in ponds and water races.

The Keewai farming system is adapted to New Zealand conditions and is unique in its hands-off approach. Other countries have more intensive systems. An adult Koura can reach mm depending on the species. Our hook-less catch and release pond allow both kids and adults to interact and have fun while also feeding these lazy crustaceans.

What do Koura eat? The tank was about half a cubic metre in size and had an artificial cover, plus natural weed for food and cover. I collected three males and three females, put them in the tank and left them to it.

I fed them worms and salmon food, and the natural weed was also available for them to eat. By March we had a small salmon farm built and fish in the water.

At that time David Smythe, who had done our consent work for the farm, said if I wanted a partner to help get the koura farm going to give him a ring. The first trials were very basic, using some large plastic tanks, just to establish growth rates and survival in the first 12 months. These were only partially successful, as the growth rates were good but the survival rates were affected by cannibalism.

We determined that koura needed lots of room and a lot of cover. Two races were dug out in the natural gravel and compacted to stop most of the water loss to ground. Water was supplied by gravity, just like a flow-through salmon farm. The races were left for 12 months to become just like a natural stream, with lots of weed and grass cover, before being stocked.

Over the next few years we had to find the best way to grow koura. We started by leaving things natural and relied on natural recruitment and harvesting what was ready each year. The system had to change, so we decided to have separate classes for each year.

For this to happen we had to have a separate pond for broodstock. Over the next six years we did three different trials, ranging from using a hatchery to get juveniles to stock races with females in protected baskets to hatching out young directly into predator-free races.

This gave us the chance to selectively breed for growth and colour. We have now settled on a system of hatching out fish into dedicated rearing races until they are 12 months old.