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Scientist works on 'super yabby' |
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Farming yabbies is not new in Australia. In
fact its a well established industry in the west and has
become increasingly common in other parts of the country.
But until now the industry has relied on wild yabby to
provide breeding stock, something that CSIRO researcher Dean
Jerry believes needs to change. |
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"Most of the research to date has been concentrating on
trying to improve the cultural environment and the husbandry
of this animal, unfortunately my attitude is that it is just
as valid that you maybe try and change the animal to suit
the cultural environment as it is to change the environment
to suit the animal," CSIRO Researcher, Dean Jerry said.
At the moment he estimates that most farmed yabbies are only
one to five generations removed from their wild relations.
This means that farmers are reliant on favourable conditions
to produce the number of yabbies required to make their
operations viable.
"As soon as you stop providing the animal with good quality
food or good quality water its production will decrease but
with genetics the gains that you make they'll always be
added on and they'll always be with you so even if the
cultural environment deteriorates you should still get high
production," he said.
"One of the advantages of genetic selection in aquaculture
species is that you not only breed an animal that's going to
be faster in growth but the animals should be more of a
uniform size which makes the marketing and harvesting of
these animals a whole lot easier," he said.
To achieve genetic improvement Dean Jerry and his team
searched far and wide for the fastest growing yabby
populations.
"So what we did is we went out and selected five populations
of yabbies from as diverse environments as we can from
western Queensland to the Snowy region to western Victoria
to try and find populations that just might naturally have
had genes for good growth that just naturally these animals
might have grown faster without us doing anything," Dean
Jerry said.
By crossing these two strains they have seen a fifty per
cent genetic gain and they are hoping to see a further
fifteen per cent this year.
"We are primarily selecting for growth rate, we are trying
to breed yabbies that will be heavier at a certain age,
probably about six months and also we are looking at tail
length trying to breed a yabby that is slightly more longer
in the tail and therefore should have more meat in the
tail," Dean Jerry said.
But tracking their progress is not so easy as the yabby, or
cherax destructor, regularly shed their shell.
Its during this malting process that they are most
vulnerable as these animals have cannibalistic tendencies.
They also have hundreds of offspring making them very
difficult to identify.
"With yabbies and crustaceans and fish its a lot harder and
particularly with crustaceans because they malt as they grow
so you can't use any sort of external tags because they'll
be lost each time they malt so identity is a big problem,"
Dean Jerry said.
By injecting the yabbies with a fluorescent dye, researchers
are able to monitor which family each animal is from to
prevent inbreeding.
While the gains are impressive so far it is not yet enough
to see the yabby industry really take off on the east coast.
Brian Royce owns a property just north of Newcastle on the
New South Wales coast. About eight years ago he decided to
diversify.
"At the time the cattle market was terrible and we thought
we had plenty of rainfall, good clay soils it was the in
thing at the time we started off small and purchased a dozer
which was end of everything we just built more ponds," Brian
Royce said.
He now has about one hundred ponds on just under ten
hectares where he grows yabbies.
But it hasn't been easy, even though he is confident there
is a market for these crustaceans, producing large enough
quantities of a decent size has proved very difficult.
The biggest problem - predators.
"On the coast here is an eel problem which we've partially
solved with eel fencing, the other one is bird predators
which is you've got night herons and you've also got
cormorants and shags the other problem too is you've got
water rats because we are on the coast and we are on a river
system they are the main problems," Brian Royce said.
Brian Royce sees his future in exporting yabbies as much of
the local market is supplied by yabbies from Western
Australia. But to do this he needs a continuity in supply.
"We have tentatively formed a co-operative, there's about
six farmers there's potential to pull in a lot more farmers
in this area and our idea was to work together as a
co-operative helping one another on farm," Brian Royce said.
To him research into improved varieties of yabbies is
crucial if his business is to take off.
"If we can the right information to grow larger and quicker
yabbies for export its mainly an export in my opinion we are
looking for a larger yabby and that sort of thing," he said.
Just south on the Pacific Highway Geoff Fry has also
invested heavily in yabbies.
He's employed aquaculture specialist Laurie Tomlin to run
the operation which combines silver perch with the yabbies.
"What we looked at was maximising the use of the available
area we've got to maximise our returns so polyculture was
one way of doing that, the fish are in the mid water level
of the pond and the yabbies inhabit the bottom of the pond
and the yabbies also aid in looking after the pond and aid
in the water quality of the pond by eating the stuff that
the fish don't like, the waste," Aquaculture specialist,
Laurie Tomlin said.
"There's a very strong market for yabbies at the moment -
we're looking to export markets."
They also want to capitalise on the export market but like
Brian Royce recognise it is not something that will happen
overnight.
"We need some time to build our stocks up because the
preferred size that goes into the export market is the
larger crayfish which can take up to 10 to 12 months to get
to the size of a hundred grams plus which is their preferred
size," Laurie Tomlin said.
Despite a significant capital outlay it may be years before
they are able to get into such markets.
"The biggest problem with yabbies is to try and grow the
numbers and we all know that you need a certain volume to
create a certain market, yabbies are one of those items that
need to be intensively grown to achieve the tonnage to
create the market and that seems to be our biggest problem
at the present time to get the numbers to create those
markets," Laurie Tomlin said.
And while research like that being done by Dean Jerry is
useful they are also trying to improve productivity by
segregating the male yabbies into separate ponds.
"There are regimes where you stock male only ponds so you
can achieve up to 70 per cent more growth because they are
not competing against each other for the female crayfish
they are concentrating more energy on growing so there are
ways of achieving better growth," Laurie Tomlin said.
Neighbours, Alyn Overton and Danielle Cox are also
experimenting. They have covered their ponds with a series
of nets after suffering a devastating blow early on.
"About 18 months ago we lost all of our stock over a six
week period, the cormorants came and they were able to take
everything we had only in six weeks and the only way we
could see to stop it was with netting," Danielle Cox said.
The birds and other predators remain a problem, they've even
got the dogs taking part in their control program.
"The netting keeps out the birds we have a boundary fence
the eels can't get through and our drainage system
discharges about one and a half meters above the ground so
the eels can't get up into the drains, water rats are the
only thing that are difficult and we are thinking that we
might run electric fences around our boundary fence to try
and scare the water rats away," Alyn Overton said.
Like the other farmers in the area they hope one day to move
into larger yabbies but for the moment most of their sales
are into the bait market.
Their original stock came from the wild but they've been
working to improve that.
"They breed like rabbits and we've had an indoor breeding
program going as well just to get us up to speed on how many
they have, how long it takes and what conditions they like
but the breeding's not the problem its making sure that they
can get through the small stage and up to bait and beyond,"
Danielle Cox said.
For all three farms while the potential is there the profits
are yet to be seen.
Even though there is confidence that there is a market for
the yabbies, until there is the ability to produce
consistently high numbers reaping the rewards of such
substantial investment is not quite a reality.
"This sort of research that we are doing I think is very
critical not only for the yabby industry but all aquaculture
industries in general, because of this reason we are farming
inferior productive stocks, we are not maximising the
genetic potential of the animals we are farming and because
what we are doing here is that we are trying to help an
embryonic industry and at the moment in Australia there's
not much help for industries that are fledgling and trying
to get on their feet," Dean Jerry said.
CONTACTS
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Brian
Royce, Royce's Crayfish
PH: (02) 4997 6607
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Dr
Dean Jerry, CSIRO Researcher
PH: (02) 6776 1322, Website:
www.csiro.au
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Laurie
Tomlin, 12 Mile Fish n Chip
PH: (02) 4997 5697
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