| Background |
With a global emphasis on ecologically
sustainable development of natural resources, it is logical to integrate,
where possible, appropriate farming practices to enhance farm productivity
and water-use efficiency. Water is currently under-utilised in irrigated
farming systems in Australia as a result of routine, single-use only. Long
term sustainability factors and water management costs to the industry
and the community at large indicate that farmers will need to diversify
and increase total farm productivity and profitability, as well as conserve
water. With such increasing pressure on Australia’s water resources, integration
of water uses should be considered. In other parts of the world, in particular
Israel and various Asian countries, integrated agriculture/aquaculture
farming systems are highly developed and make considerable use of the available
water resources for fish production on a sustainable and synergistic basis
with various forms of agriculture. There has been no major commercial effort
in this area by Australia to date, although interest from the farming community
appears to be increasing rapidly.
The advantages of integrating aquaculture and irrigation
farming include
i) to increase farm productivity without any
nett increase in water consumption
ii) to enable diversification into higher value crops,
including aquatic species
iii) to enable utilisation of otherwise wasted on-farm
resources
iv) to reduce nett environmental impacts of semi-intensive
farming practices
v) to achieve nett economic benefits by offsetting existing
capital and operating farm costs
|
| Research |
The trials were undertaken in
the Central Goulburn Irrigation Area of the Goulburn-Murray Irrigation
District (GMID) in north-central Victoria, during each irrigation season.
Various experimental integrated systems were established and evaluated,
viz.
1. Channel Ranch Cages - floating cages in irrigation
channel
2. Storage Cages - floating cages in an on-farm water
storage dam
3. Groundwater Tanks - floating cages in round, prefabricated,
above-ground, PVC lined tanks)
4. Groundwater evaporation basin in which a single large
(20m3), floating cage was located
5. A control system consisting of purpose built, earthen
fish ponds at a local commercial fish farm, subject to optimal, ambient
environmental conditions.
Industry participation in the project, through contribution
of on-farm resources and by operation of the experimental systems, was
under the terms of a Memorandum of Understanding between the relevant parties. |
| Outcomes |
Technical
Technically viable integrated aquaculture system designs
have been developed, trialed and tested for immediate application and/or
further refinement within the GMID. Such systems are relatively low-cost,
"user-friendly" designs, the fabrication of which can be done without specialist
skills and using non-specialist, readily available materials. Fish survival
needs to be enhanced by ensuring that the systems are secured against disturbance
by intruders, vandals and other potential villains, and natural predators
such as water rats. System design needs to be refined in a way to ensure
that trade-offs against capital outlays are minimised. Although not conforming
to the hypothetical model in the actual trials, silver perch may indeed
prove to be a more suitable species for integrated aquaculture production
under warmer ambient climatic conditions at more northerly latitudes. Within
the GMID, a number of alternative fish species (other then silver perch),
may prove to be more suited to the cool temperate ambient water temperatures.
An alternative approach with slower growing species at
more southerly climes, such as silver perch in the GMID, is to develop
integrated systems which specialise in producing larger numbers of smaller
fish to on-sell to other growers as advanced stockers in order to finish
off for the market. Whichever species is selected for integrated production,
seedstock availability is a critical factor which needs to be considered.
The limitations of seasonality may dictate that multiple species need to
be cultured within integrated systems under ambient temperatures in a temperate
climate such as in Victoria and southern NSW. Integrated aquaculture produce,
such as silver perch produced in the present study, has the potential to
achieve satisfactory market standards of quality control, in terms of sensory
attributes.
Environmental
A preliminary nutrient mass balance model is available
as a useful tool for monitoring and regulation of integrated aquaculture
development as part of irrigated farming systems, in particular to ensure
conformity with existing nutrient management strategies, catchment nutrient
loadings and associated regulations. The conceptual nutrient mass balance
model indicates that integrated aquaculture production of silver perch
in the GMID typically releases nutrients into the surrounding environment,
that the primary source of those nutrients is the feed used to grow the
fish, and that the discharge to the environment can be quantified within
a conceptual framework. As stated above, the amount of N and P discharged
into the Goulburn-Broken Catchment by such an industry is directly related
to the level of production. The nutrient mass balance model developed in
the present study has a number of limitations which should be considered
when interpreting results, and which require more refinement and appropriate
validation.
Economic
The cost-benefit analysis of the hypothetical system designs
in the present study is limited to site specific considerations only. Whereas
this is an appropriate means of comparing systems relative to each other,
the costs and/or benefits of integrated aquaculture practices at a macro
scale are not able to be evaluated. The socio-economic impacts of integrated
aquaculture within the family unit are not fully evaluated within the present
study. The very nature of integrated aquaculture as a low cost form of
"light industry" lends itself readily to encouraging participation from
all members of the family other than the traditional income earners.
Those integrated systems which utilise existing infrastructure
(ie. operator-owned) and water allocation, for which the operator has to
pay no "extra", and for which some additional benefit can be achieved by
the operator through on-farm cost-savings on fertiliser application, with
no increase in water consumption and/or nett environmental impact from
integrated aquaculture operations, are more likely to be economically viable.
Those integrated systems which are newly established (ie.
not utilising existing, operator-owned infrastructure), for which the operator
has to pay "extra" for water access, and for which there may be some additional
cost incurred by the operator to offset any possible environmental impacts
from integrated aquaculture operations, are likely to be economically marginal
at best. The economic viability of integrated aquaculture systems increases
markedly with decreasing feed costs, more efficient feed conversion, larger
numbers of cages and improved fish survival (by whatever method). The economic
viability of integrated systems as described in the present study is likely
to be dependent on the establishment of regional business clusters or networks,
in which a number of operators cooperate to create a critical mass of on-ground
production capability. |
| Implications |
The implementation of a national
Integrated Agri-Aquaculture Systems R&D strategy, in conjunction with
a compatible program of industry development over a five year period, is
seen as an appropriate way to ensure a high degree of relevance to and
acceptance by industry in the process of exploiting the opportunities.
Broadly speaking the key requirements of such a plan should
include:
· The need
for relevant background information as an extension resource.
· The need for an industry-wide
economic development strategy to assist business planning for existing
farmers and new investors.
· The need for a review
and collation of all Federal, State and local government legislation, policy,
planning and management guidelines relevant to integrated aquaculture development
in Australia.
· The need for more
biological and technical information relevant to development and implementation
of integrated aquaculture practices in Australia.
· The need for industry
extension support, training and education for new operators/investors and
resource managers, regulators and legislators.
In conclusion, in order to fully exploit commercially the
results of this work, and indeed the intrinsic merits of integrated aquaculture
as a concept, it is suggested that government at all levels, Federal, State
and local, will need to actively engage farmers and the water industry
through a proactive and targeted development program.
The broader requirements for communicating the opportunities
presented by agriculture-aquaculture systems integration throughout regional
Australia are best dealt with in the context of the National R&D Strategy
for Integrated Agri-Aquaculture Systems, presently in preparation by RIRDC. |
