We need freshwater to help us raise and keep our fish healthy. Our highest freshwater use is in our marine farming operations for bathing our fish. We bath our fish in freshwater to rid them of an amoeba safely and without chemicals. We also use fresh water in our hatcheries and in our fish processing facilities. Across all areas of our operations, we work actively to continually reduce our freshwater use.
Bathing – Tasmania is a unique environment when it comes to salmon farming. The relatively high water temperatures promote the settlement on the gills of Amoeba, a single celled microscopic animal. The Amoeba multiply and reduce water flow at the gill surface that can limit oxygen supply to the fish causing lethargy and, if untreated, death. Bathing fish in fresh water cures the salmon of amoeba and the salmon are happy in either freshwater or seawater.
Huon is the first company globally to use a well-boat for the purpose of bathing fish in freshwater. What this means is that rather than using large liners full of freshwater, fish are transferred into the wells of a boat to swim around for a few hours before they are returned back to a pen.
Where freshwater liners only provide single use of freshwater before it is released back into the sea, a well-boat can clean and reuse the same supply of water up to six times. This has a significant impact on our freshwater efficiency for marine farming.
Flow-through hatcheries – Flow-through hatcheries are freshwater hatcheries which draw freshwater from a local source such as a river and then release the water back to that source after use. Before freshwater is released back it is cleaned through drum filters to ensure we effectively minimise and manage any potential impact on the environment. Flow-through hatcheries are issued with a non-consumptive water licence which results in a water usage reading of zero with all the water returned to the source in a sustainable manner.
Recirculation hatcheries – Recirculation hatcheries treat and reuse freshwater, meaning that they do not discharge any water used in operations back to the natural source, and are classified as consumptive. A small percentage of freshwater will become waste water and is not reused; waste water is either irrigated onsite or provided to neighbouring farms or orchards for irrigation.
Parramatta Creek processing facility – Our fresh and value added processing facility is located in Sassafras in the North of Tasmania and waste water is used for irrigation.