Over the last few decades there has been a rapid decline of our native finfish species within our river systems however demand for fish still continues.
The aquaculture potential of our four main native finfish species, Murray cod (Macculochella peeli), silver perch (Bidyanus bidyanus), golden perch or callop (Macquaria ambigua) and catfish (Tandanus tandanus) therefore shows potential with each species demonstrating promising aquaculture characteristics (Appendix 1).
South Australia to this point in time has had relatively little success in the farming of freshwater native finfish. This can generally be attributed to the fact that SA has little freshwater availability when compared with other states.
Consequently little information is available regarding best practice techniques to farm these fish in SA. Therefore until recently, there have been few attempts to culture native species of freshwater fish on a commercial scale in South Australia.
Status in other States:
Hatchery production and aquaculture of native finfish, particularly Silver perch, has been occurring in other states of Australia for a number of years. Narrandera Inland Fisheries Research Station in New South Wales has developed techniques for the successful breeding of freshwater native finfish which have been distributed to a number of hatcheries located around New South Wales and Victoria (Appendix 2).
The Silver perch industry in NSW has increased substantially since 1994 with production levels increasing yearly. Silver perch farming in aquaculture ponds also occurs in Western Australia, Victoria and Queensland.
Murray cod aquaculture in ponds has been occurring in predominantly in NSW and also in Victoria. Murray cod has recently been recognised as a promising candidate for intensive recirculation aquaculture.
It was originally thought that Murray cod would be unsuitable for aquaculture due to its aggressiveness however it has been proven that when cod are stocked within tank systems, competition between the fish declines.
Callop and catfish aquaculture has occurred in both NSW and Victoria on a limited basis using both recirculation systems and ponds.
Rules and Regulations:
Before someone can venture into native finfish farming an aquaculture permit must be obtained through the Aquaculture SA within Primary Industries and Resources South Australia (PIRSA). This permit will record the applicant as a registered fish farmer and therefore enable them to stock ponds or dams or tanks with fish and sell their produce.
Before a permit may be granted by the Aquaculture SA for a land-based applications it may be required that approval be sought by the Department of Environment and Heritage (DEH), the Environment Protection Authority (EPA) and local councils.
Site Selection:
Whether you are looking at setting up an intensive or extensive native finfish farm or hatchery it is important that a suitable site is selected. The following factors are considered to be important when selecting a site to ensure biological, practical and economic feasibility of a fish farming venture.
Water Supply:
The well being of fish is ultimately dependent on the abundance and quality of the available water.
Abundance:
A regular, abundant water supply to the ponds, tanks and hatchery site is absolutely essential for the maintenance of healthy fish stocks, and the efficient incubation of eggs and the rearing of larvae and juveniles. The quantity of water available will determine the holding capacity and production potential of a farm.
Quality:
A supply of good water is essential. Poor water quality will result in reduced survival and /or growth at all stages of a fish’s life cycle. The water supply must be free from sewage and other dissolved wastes, heavy metals, oils, pesticides, herbicides, chlorine, methane, hydrogen sulphide and other poisonous substances.
Waters of high turbidity caused by silt and clay colloids should be avoided because it may reduce fish growth rates and resistance to disease and may also affect gonadal development. High turbidity may also depress pond temperatures to well below those required for spawning.
Turbid water impedes the observation of eggs and larvae in the hatchery and the suspended particles can clog filters.
Source:
Water for fish farms can be drawn from many sources such as runoff from catchment areas, rivers and creeks, small dams and lakes, irrigation canals and bores. The type, size, location and topography of a farm may determine the best or most practical source of water.
Bore water has the following features that make it very suitable particularly for hatcheries and use within recirculation systems.
- Regular dependable supply
- Free of pathogens,
- Free of organic, agricultural and industrial pollution
- Free of suspended particles and so allows observation of eggs and larvae and eliminates siltation on eggs
- Relatively constant temperature
- Free of undesirable fish and aquatic organisms
Some sources of bore water are deficient in oxygen and contain excess nitrogen and harmful gases such as methane and hydrogen sulphide. However these limitations can generally be overcome by storing and aerating the water in a reservoir prior to use.
Water supply from domestic supplies should be avoided because it contains chemicals such as chlorine which may be present at levels toxic to fish.
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