New Zealand Clearwater Crayfish
ALL PURCHASE ENQUIRIES
David on crawlyfish at gmail dot com
Please note we do not sell to stock ponds streams
unless a fish farm permit is held
we do not export our koura – only available in
Clearwater Crayfish (Koura) Ltd (NZCC) is a private company established in
1996 by Peter Wilhelmus and David Smythe to farm and market the North
Island species (Paranephrops planifrons) of New Zealand freshwater
crayfish known as koura.
This new pioneering
venture in New Zealand
is now up to commercial production.
NZCC farms and
markets Koura on the Ormond property under the fish farm licenses held by
Ormond Aquaculture Ltd.
finding some distinctively red coloured juvenile koura in the farm, those
were set aside and raised in an independent circular tank. With careful
selected breeding, a significant stock of pure red koura has been
developed. It appears that a red gene
has been developed in the NZCC general stock and we have been able to
isolate it by trial and error.
are now able to supply the aquarium market within New Zealand with this unique
natural creature. At the moment,
purchase of NZ Red Glory is only available direct from the farm as shown
in the Sales section previously.
interest in this colourful species should directed by email.
New Zealand Red Glory
Bred at New Zealand
Clearwater Crayfish farm
established, the NZCC koura farm was part of an organic multi species
freshwater aquaculture complex based on a small mixed sex salmon
farm. The farm is located in
Wairau valley about 35km from Blenheim. Just “upstream” of
the Wairau Valley settlement.
The farm was only
the second in New
Zealand to be established and market
farmed koura. The first being near Alexandra.
There was no
information or existing practical experience to build upon so the farm
has been developed by the partners through hard work, trial and error,
and reading literature from Australia,
USA and Europe to glean ideas. David Smythe has visited
yabbie farms in Australia.
aquarium trials in 1993 and 1994, field trials began in 1995 and farm
construction began in March 1997 with a broodstock pond of some 100m² and
two races totalling about 80m in length and 5m wide.
broodstock pond and first two growing-on races 22 November 1997
By March 2011 some
1300m of raceway are established and hatchery facilities expanded into
the old salmon farm hatchery races and growing on ponds. Since the demise of the salmon and
loss of organic status the whole aquaculture area has been converted to
farming koura and experimenting with other fish species.
Water is diverted
from the original Ormond Aquaculture Ltd salmon farm settling pond via a
rock screen and head race to the growing on races. The Koura environment
has been developed and managed to achieve as closely as possible natural
conditions but with considerable enhancement such as eliminating
predators from all sources and providing abundant natural cover and a
female about 120gm and 140mm TL with about 350 eggs
mate in the broodstock pond or are collected and selectively mated in
tanks. While selective mating
remains an ongoing experimental process, it is showing very good results
and now all koura are farm bred. Berried females are collected from the
broodstock pond about 4 months after mating and transferred to the
hatchery. Females selectively mated are placed in the hatchery as soon as
the fertilised eggs are cemented to the pleopods.
One of the Founding Fathers
When all the
hatchlings have left the female she is returned to the broodstock pond
and the hatchlings remain in the hatchery until about 10 to 15mm overall
length (TL) then transferred to a growing-on race. During that time they
have undergone at least four if not five molts and the shell has
'hardened up so that the translucent effect of the baby hatchlings has
disappeared and they have taken on a brown-faun colouring.
We have often been
asked by students if the colour of koura is influenced by their
surroundings or container they are kept in. We have not been able to
identify any colour change in adults, hatchlings, or juveniles that is
attributable to the colour of the container. The only colour change we
have seen is the natural change from translucent hatchlings to brown-faun
juvenile. Except, of course, for
the new NZ Red Glory koura selectively bred in the farm.
size of about 100mm TL and 45 to 55gms weight is achieved in about 20
months while up to 105-115mm TL and 90 to 110 gm is achieved in about 2 years
3 months. Larger size Koura of
around 130 to 150 mm TL and 120+ gms have grown in about 3 years.
Pincers on left: 160mm - 6 males with 3 females on
Size range: males 150-165 gms, females 80 - 95 gms.
improved over the years with females carrying about 250 to 400 eggs on
average by natural selection. The selectively mated females have had over
In August 2000
females were found mating while some were found with eggs just hatched.
This is both late (some two months) and very early (3 months)
respectively and looks promising for possibly having a wide spread of
breeding through the year, if the trend continues. However, the timing
may be influenced by the La Nina weather pattern over New Zealand the last three
years bringing gradually warmer temperatures.
The farm now keeps
about 2000 breeding females which have been grown in the farm. This broodstock provides the basis for
continuity of supply for full commercial production. The first rotation
was initiated in February 2000 when some 35000 hatchlings were
transferred from the hatchery to the races. Many more hatchlings have
been carried to survival in the hatchery each year, and our target annual
commercial harvest of around 1.5t
is closer to being achieved.
The farm complex was
originally set up as an organic freshwater multi-species farm and OAL
received two environmental awards in each of 1977 and 1979. Sadly organic status no longer applies
to the farm due to water pollution factors outside the control of farm
management. As a result of the
water pollution, salmon are no longer farmed. Fortunately, by August 2012 the water
pollution factor has been resolved.
aquaculture complex remains GE free and organic farm principles are
The directors are
confident that the system developed is sustainable and in harmony with
the environment. Achieving organic certification for both the salmon and
freshwater crayfish farms was a major achievement that sadly did not get
the support it required from the local authority.
A feature of the
farm is the careful management of the environment in which Koura thrive.
A high level of natural nutrition is promoted but supplementary feeding
is essential to achieve growth rates desirable for a commercially viable
The original high
protein organic food was originally developed utilising all solid waste
from processing salmon. At that
point in development, the farm complex was operating as a zero waste
entity. For a time, suitable
'waste' fish was purchased and processed into our fish silage on site.
The fish silage was mixed with other organic products to produce the
koura food. The koura food is now
made at an organically certified commercial enterprise to the diet
The koura are
generally fed every second evening if all the previous feed out has been
consumed. However with the
continual rise of the cost of food ingredients, alternatives are being
At this stage there
is no scientific data to show feed out rate per kg of koura or the
conversion rate, but a procedure for achieving that is being developed.
No chemicals or
hormones are used.
Koura are harvested
by trapping in 'opera house' traps and by partially draining the race and
collecting Koura by hand.
Before sent to
market the koura must be held in clean running water without food for up
to two days so that the gut line is purged. This enables the koura to be
presented with a clean white tail meat.
As a general guide,
koura should be treated similar to fresh scallops. Do not over cook!!!.
Koura should be
chilled in a freezer for about 2 - 3 hours before dropping into boiling
water or putting on the barbeque. The shell will turn a bright red. Cook
for about 1½ minutes then drop into a large bowl of iced cold water to
arrest the cooking. The cooked
colour is a real stand-out in any food preparation or presentation. Do not put so many koura into the water
that will arrest the boiling as this will produce an unattractive blotchy
There are several
ways the cooked koura can be presented and it is really over to the
imagination of the chef. If further cooking is to be done, such as sauté
the tail meat in garlic or herbed butter, the initial cooking time should
be no more than 1 minute and secondary cooking another minute.
One male and five females; four showing eggs cooked
on body as 'crayfish caviar'
Pile of male koura
Koura tails, sautéed in butter and garlic with honey
glaze and dipping sauce
There are many
things NZCC would like to do by way of research and development but
several factors limit the immediate prospects for serious research.
development is on going with the hatchery to increase survival rate of
hatchlings and to develop a process to triploid koura.
involves other fish species with potential to be farmed in a
multi-species environment is progressing as funds allow.