14 November 2001
Summary: World's first whitebait ranch set up in NZ, to breed, feed, release and capture the fishy delicacy finds hope
from research into spawning, rearing and homing habits.
New Zealand's first whitebait farm has been set up with the objective of learning more about, and increasing the
numbers, of this popular delicacy.
Scientific research into New Zealand's reducing whitebait resource could mean more of the fishy delicacy for gourmets,
as well as the potential revival of a once important fishery.
Biological consultant Charles Mitchell is carrying out the whitebait research with the aim of breeding, releasing and
recapturing ever-increasing numbers of whitebait.
The research underpinning the intricacies of feeding, housing and even tagging New Zealand's most expensive finfish,
has been helped with funding of around $21,000 from the Foundation for Research, Science and Technology through its
Grants for Private Sector Research and Development scheme.
In its heyday, the Waikato River produced around 100 tonnes of whitebait a year, and even supporting two small
canneries. Now, due in part to environmental impacts and what Charles Mitchell calls a 'plunder as you go' fishing
mentality, less than three tonnes is fished from the Waikato each year.
The research undertaken at the Mitchell's whitebait 'ranch', which he believes to be the first in the world, now
confirms that bulk spawning and rearing of whitebait larvae is indeed possible. The whitebait are then seeded into the
ocean, returning four months later as the delectable fresh-run whitebait.
Homing is the simplest explanation for the regular annual runs of whitebait into rivers and streams all around New
Zealand, according to Mr Mitchell. "Whitebait are actually the Southern Hemisphere relatives of salmon and trout fish
which are well known to show homing behaviour. Although many will die, stray into other rivers or be caught by other
whitebaiters, we need only half of 1% of what we release to come back each year to be viable," he says.
The Mitchell's whitebait ranch, on the shores of Raglan Harbour is an example of kiwi ingenuity at its best. Tide and
gravity is used to pump salt and freshwater and even car hub-caps have been used to build automatic fish feeders.
"We have done a lot of experimental engineering and biological work in finding out the best way to build and manage
tidal ponds, and also to grow the healthiest adult whitebait. Technology New Zealand's funding has been very helpful in
allowing us to look at a number of different possibilities to find the optimum answers.
"A spin-off benefit has been that we've been able to apply the knowledge we've gained in whitebait to breeding native
trout which live in forest streams and have become very rare as the native forests have been cleared," he says.
Mr Mitchell's research aims to boost numbers of baby whitebait, then release them into the sea, with the idea that the
returning adults will improve not only his own stock numbers but also provide flow-on benefits for other whitebaiters
upstream of his ponds.
"We have proved that farmed whitebait have a big reproductive advantage as they are fed better and grow bigger in our
ponds as well as being protected from disease and predators. That means a greater chance of survival and in- turn more
progeny surviving, with a increase in numbers overall, this approach leads to a surplus which can be sustainably
harvested" he says.
With a hectare of whitebait ponds now in operation, Mr Mitchell's whitebait farm is well on the way to a goal of a base
stock of around 200,000-plus adult whitebait. He says what appears on the surface to be a relatively hit and miss affair
(capture, breed, feed, release and hope they return) is actually starting to look at being viable, with the whitebait's
homing characteristics resulting in a rising number returning from the sea to the ponds each year.
They are, he says, a beautiful and entrancing little fish, worth more than its weight in gold as a tasty source of
dietary calcium and with the potential of enhancement to restore a fishery nearly lost from many parts of New Zealand.
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