[ASC-media] Media release: prawn farms clean up

CRCA Media crcamedia at starclass.com.au
Tue May 9 10:51:14 EST 2006

CRCA Media Release 06/09

May 9, 2006


Improved environmental performance by Australia's prawn farms is delivering a
superior product to consumers - and higher returns to farmers and the nation.

One breakthrough has enabled prawn farmers virtually to double production from
the same amount of feed, while at the same time preventing the environmental
pollution caused by prawn culture in other countries.

"For the past decade we have been finding ways which improve both the
economic and the environmental performance of prawn farms," says Dr Nigel
Preston of CSIRO and the Cooperative Research Centre for Aquaculture.

Scientists have investigated water usage, nutrients, and discharge licensing
problems. Prawn farmers are also using software designed by the CRC to assist
with farm business management.

"From the prawn farmers' standpoint, it is a matter of taking on board the
improvements which science has made available. Researchers have been
working closely with farm managers, trying to understand the processes of the
farm in real time and in a real environment."

A recent (2005) study by The Allen Consulting Group found the prawn industry
has invested more than $15 million to improve its environmental performance,
using practices developed by the CRC.

"The results of the research provided new insights into prawn pond and
discharge water management," says Duncan Buckeridge, formerly with Allens.
"This had significant, quantifiable impacts on industry practices."

Dr Preston says that today, all Australian prawn farms use discharge water
treatment systems which meet the nutrient discharge rate established by CRC
research, and that this has much more than an environmental benefit.

"As the 'used' water is discharged, it is recaptured and re-circulated, leading to
substantial savings in water and pumping costs, but more importantly giving the
prawns a second chance to absorb the nutrients in the water.

"Up to three quarters of prawn farming costs are feed," says Dr Preston. "Only
part of the food pellets are initially eaten by the prawns themselves - the rest
feed various micro-organisms, phytoplankton, fungi and so on.

"All of these small organisms which have eaten the prawn food are themselves
food for prawns - if they are not washed away in the pond discharges.

Recapturing the effluent, allowing the sediment to settle, and pumping it back to
the prawns gives them a second chance to extract the nutrients that originated
from prawn feeds.

"This means that the prawn farmer doubles the value of the expensive feed which is fed to the prawns in the first place."

Dr Preston says that much of the research leads to better hands-on
management, but the research itself involves sophisticated tracking of isotopes of
nitrogen and phosphorus throughout the farming cycle.

"To make practical improvements, we needed some very fine analysis," he says.
"We needed to be sure that the isotopes we were tracking were in fact from the
introduced nutrient, rather than from naturally-occurring algae or other sources."

Dr Preston says that unlike most farmed animals, the parents of farmed prawns
still need to be captured in the wild. All farmed prawns are originally wild stock
captured by trawlers at sea. A key issue for the industry is to progress beyond
their current reliance on wild broodstock to the use of domesticated, selectively
bred stocks.

"Having successfully developed the world's best practices in the environmental
management of prawn farming, the industry is now focusing on other critical
issues including a major initiative by the Australian Prawn Farmers Association to
achieve commercial domestication of the Australian black tiger prawn," he says.

"The first commercial trials are now in progress, but there is still a complex
program of research to be completed, as there are still many unknowns: the
preferred environment for black tiger prawns; how susceptible will they be to
diseases; what are their rates of reproduction? - the sorts of questions that all
livestock producers have faced during the development of their respective

Dr Preston says that a combination of Australia's scientifically-based prawn farm
management, plus the anticipated success of a black tiger prawn breeding
program, will consolidate Australia's position at the forefront of world aquaculture.

Overall, Australia is $1.14 billion better off, or sixty cents wealthier for every dollarinvested by the Federal Government in CRC research, according to the AllenConsulting Group report. This found that real consumption in the economy wasup by $763 million, real investment by $417 million and tax revenue by $66m asa result of CRC research.

Media Note:The Cooperative Research Centres Association (CRCA) will hostits annual conference in Brisbane, 17-19 May. Titled "CRCs: Making an Impact", the conference will feature a cross section of the nation's brightest minds, leading scientists, academics, business people and users of research.

More information:
Dr Nigel Preston, CRC for Aquaculture and CSIRO, 07 3826 7221
Mr Martin Breen, Chair of R&D Committee, Australian Prawn Farmers
Association, 0402 689 565
Dr Peter Montague, formerly CEO, CRC for Aquaculture, 08 8207 5302
Duncan Buckeridge, formerly with The Allen Consulting Group, now with
Insight Economics, 03 9909 7545 or 0425784107

Prof. Julian Cribb, CRCA Media, 0418 639 245
More science stories: http://www.sciencealert.com.au

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