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Eels, Pearls and Algae - Aquaculture in Australia
Georgina McGill
Science, Technology, Environment and Resources Group
Aquaculture is the farming of fish and other aquatic animals (including
pearl oysters) and plants in either a saltwater or freshwater environment.
Most of the world aquaculture production (about 60%, excluding plants)
is of freshwater fish and originates from inland areas.(1) Unlike agricultural
production, an aquaculture 'farm' is not a single type: depending on the
species it may be a series of ponds (prawns); a dam (yabbies); ropes suspended
in the sea (mussels); or sea cages (salmon, tuna). With the global catch
in decline through overfishing, pollution and marine habitat destruction(2),
aquaculture is regarded as an increasingly important source of food. In
1993 aquaculture produced nearly 16 million tonnes of the total world
fish production of 101 million tonnes and contributed 21.8 percent of
the world food fish supply.(3) Asia produced 84 percent of world aquacultural
production in 1992, with China alone accounting for 49 percent (6.8 million
tonnes). Australia's production of edible, high-value fish, crustaceans
and molluscs in 1994 - 95 was only 23 507 tonnes.(4)
Size of industry
Aquaculture is a rapidly growing industry in Australia, with the value
of production more than doubling from $158 million five years ago, to
$419 million in 1994 - 95.(5) It now accounts for nearly one quarter of
the total value of Australian fish production. Pearl oysters are the largest
earners, earning $206 million in 1994 - 95 compared to $130 million the
year before, while the value of farmed salmon rose 40 percent in 1994
- 95 to $67 million.(6)
Nature of Australian aquaculture
Australian aquaculture is not typical in that most of the operations
are on or near the coast,(7) characterised by a relatively small volume
of high-value species. Overall, more than 60 species are currently being
farmed. These include pearl oysters, Pacific and Sydney rock oysters,
mussels, prawns, freshwater crayfish, trout, Atlantic salmon, barramundi,
eels, southern bluefin tuna and algae.
Factors in success
Successful aquaculture depends on a range of factors including: site
selection; design and construction of facilities; biological techniques;
water quality and farming practices; feeding controls and suitable markets.
Depending on the country and the product different factors may assume
importance. Site selection is very important, and there are surprisingly
few sites in Australia which meet the specific land and water requirements
(and these will vary depending on the species to be farmed) once cities,
National Parks, heritage areas, fisheries habitat and wetland reserves
and areas reserved for recreation, boating and other developments are
excluded.
A primary requirement of a site is the availability of sufficient suitable
water (defined not only by quality but also factors such as temperature).
Aquaculture is a heavy consumer of water - to support the animals, replenish
oxygen and remove wastes. The quantity and requisite quality of the water
will vary depending on the species and the size of the operation. Both
the ponds and waste water require a higher degree of water quality management
in the case of 'intensive' (high stocking density) aquaculture, which
leads to high concentrations of uneaten food and metabolic wastes. Each
of the States has environmental standards for discharge water, to which
the aquaculturists must conform.
Relative ignorance
Knowledge of aquaculture has been compared with the state of knowledge
of agriculture several thousand years ago.(8) A great deal remains to
be learned about breeding, feeding and growing, and biological techniques.
Similarly, the environmental impact of aquacultural activity is poorly
understood at present. Concerns include effluent wastes; the impact on
biodiversity; degradation of land and reduced water quality from acid
soils; fishmeal requirements for some intensively farmed species - such
as salmon, which require about 3.25 tonnes of fishmeal for every tonne
produced(9) - which impact on fisheries resources; the introduction of
exotic species and diseases not found in Australia; and the possible implications
for both the ecosystem and human health of the use of chemotheraputants
(vaccines, antibiotics) and other chemicals.
Positive benefits from aquaculture include high production from intensive
farming; increased selectivity of stock for the market (size of fish,
time of harvesting, quantities to harvest); no bycatch of other species
(e.g., bycatch can be up to 90% by weight for prawn trawlers); and breeding
of stock can be used to help repopulate depleted wild fisheries.
Interest in sustainable practices
Aquaculture is attracting enthusiastic and dedicated entrepreneurs,
despite the relatively high risks. They are finding innovative solutions
to the above-mentioned concerns - including practices such as 'polyculture',(10)
which is the term for an ecologically integrated, sustainable farming
system of both flora and fauna; the use of the mineral zeolite, or oysters
and algae, as filters for wastes; and constant improvement of pond and
water management. Interest in sustainable aquaculture extends beyond Australia.
The key session of the World Aquaculture Conference held in Bangkok (January
1996) was "Policy and Management for Sustainable Aquaculture".(11)
Regional development
The potential for aquaculture in regional development has been recognised
by the states and Northern Territory. Each state government now has an
aquaculture section with a dedicated manager in the State Department which
oversees the fish production industry. Technical support is also provided,
by officers who generally go 'out into the field'. South Australia, e.g.,
has an Aquaculture Industry Development Officer who specifically works
as an aquaculture investment advisor. The Western Australia State government
announced in 1994 a development strategy for the aquaculture industry
in that state. There is also a National Aquaculture Industry Working Group
comprising thirteen state and territory representatives.
Impediments to growth
Some of the impediments to current growth of the industry in Australia
are the limited availability of suitable sites, the availability of finance
for high risk ventures and state-based regulatory constraints (which are
more onerous in some states than others).
Potential for larger industry
The future direction for aquaculture in Australia is toward a significantly
larger industry than at present, based on sound farming practices developed
for sustainability. Production will be 'niche-specific', high-value and
low-volume. The labour force will be increasingly better educated and
trained as more graduates with majors in aquaculture from tertiary institutions
enter the industry. There will be strong, interdependent links between
industry groups and research institutions, State fisheries departments
and the markets. World demand for food fish, crustaceans and molluscs
will continue to rise.
Endnotes
- Food and Agriculture Organisation (FAO) of the United Nations, The
State of World Fisheries and Aquaculture, Rome 1995 p.27
- Dr Meryl Williams, quoted inThe Australian, 8 May 1996
- FAO,op.cit., p.47
- ABARE,op.cit., p.22
- ABARE,Fishery Statistics 1995, AGPS Canberra, 1995
- ABARE,ibid..
- DPIE (Ian Hill, Jayne Gallagher, Gina Newton), "Aquaculture",
Internet
- Dr Meryl Williams,op.cit.
- Malcolm Beveridge, Lindsay Ross and Liam Kelly, "Aquaculture
and Biodiversity",Ambio, Vol.23 No.8 December 1994
- See O'Sullivan, Dos, "Plant polyculture to boost freshwater
production and profits" inAustasia Aquaculture, 9(4), July/August
1995
- Tim Walker with Philippa Clymo, "Sustainability and family farms:
take-home lessons for silver perch",Austasia Aquaculture,
Vol.10 No.1, March/April 1996
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