There are currently 16 freshwater hatcheries (land based fish farms) operating in Tasmania, producing salmonids (salmon and trout). Most are hatcheries producing smolt (immature salmon) for marine fish farms. The growth of land based aquaculture has been closely tied to the rapid growth of marine farming. Under the Inland Fisheries Act 1995 the Inland Fisheries Service is responsible for licensing inland fish farms, and for ensuring adequate safeguards for the freshwater environment through specific licence agreements.
Under the Living Marine Resources Management Act 1995, marine farming development plans are prepared, designating areas in State waters where marine farming may occur. There are 44 licensed finfish marine farming leases in State waters, which occupy a total of 2,257 hectares in six marine farming development plan areas. Each of these areas has a different set of environmental issues and management controls. Farming takes place in southeast Tasmania, in the Huon River estuary and D'Entrecasteaux Channel; at Nubeena on the Tasman Peninsula; in Macquarie Harbour on the West Coast; and in the Tamar Estuary in the north of the State.
Salmonid species currently commercially farmed in Tasmania include Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Information on freshwater fish species in Tasmania is available at the IFS website
Impacts from freshwater hatcheries and marine farms may vary significantly, depending on factors relating to both the operation (size, style, technology) and the environment, including hydrological factors, weather and climate. Impacts to water quality resulting from inland hatcheries can occur from nutrients in feed inputs and fish metabolic waste being present in the farm discharge if treatment of effluent is inadequate, and this may cause visible impacts such as increased algal growth in surrounding waters.
Environmental impacts of marine farming include changes to the benthic habitat as a direct result of deposition of fish farm waste (ie fish food and faeces) at the lease sites. Changes to water chemistry such as lowered dissolved oxygen levels, are also a potential. These parameters are monitored by the industry and regulated by government, and a range of adaptive management controls are applied in response to the scientific modelling and regular monitoring.
Environmental monitoring and controls
The environmental licence conditions require the companies to undertake regular visual monitoring of the benthic impacts associated with farming salmon at all farm sites in the State. There are a range of controls relating to the management of lease areas and to respond to any significant visual impact at defined compliance points 35 metres away for the lease boundary.