The EPA has been responsible for environmental regulation of Tasmania's finfish farming industry since 2016.
Environmental Licences and Management Controls
Anyone operating a marine or freshwater finfish farm must hold an Environmental Licence issued under the Environmental Management and Pollution Control Act 1994. Environmental licences contain conditions setting out environmental monitoring requirements and performance standards for the various components of marine and freshwater finfish farms.
Furthermore, the EPA Director has powers under certain management controls in Marine Farming Development Plans to make important decisions, such as capping emissions of dissolved nitrogen from marine farms. Marine Farming Development Plans are created under the Marine Farming Planning Act 1995, hence relevant EPA staff have authorised officer powers under that Act.
Potential Environmental Effects
Environmental impacts from freshwater and marine finfish farms may vary significantly, depending on factors relating to both the operation (size, style, technology) and the surrounding environment (hydrology, water quality, local ecology, climate).
Water quality impacts from freshwater finfish farms can occur from nutrients from feed and fish metabolic waste that is present in the farm discharge if effluent treatment is inadequate. Excess nutrients can cause impacts such as increased algal growth and changes to instream macroinvertebrate communities. Nutrients also contribute to catchment nutrient loads which can impact downstream habitats including estuaries.
Environmental impacts of marine finfish farms include changes to the sea floor habitat as a direct result of deposition of fish farm waste (ie uneaten fish food and faeces). Impacts of these wastes on the marine environment may include organic enrichment of soft sediment habitats. Breakdown of wastes also consumes oxygen which may lead to lower levels of dissolved oxygen in the water column.
Dissolved nutrients released from fish farms can also stimulate primary productivity (e.g. algal growth), which in excess may lead to eutrophication and the outbreak of algal blooms. At lower levels, dissolved nutrients can cause increased growth of opportunistic algae which may in turn affect the composition and function of nearby ecosystems, such as rocky reefs.
Other types of potential impact from finfish farming activities include emissions of noise and light that may cause environmental nuisance.
Marine Finfish Farms – general monitoring requirements
Environmental licence conditions require the companies to undertake regular underwater video surveys of the seafloor to monitor impacts associated with farming salmon at all marine farms. There are a range of controls relating to the management of lease areas and to respond to any significant visual impact under net pens and at defined compliance points located 35 metres from the lease boundary.
Broadscale Environmental Monitoring Programs (BEMPs) are also in place in most marine farming regions. The objective of BEMPs is to document broadscale trends for key environmental parameters, thereby allowing assessment of the cumulative environmental effects of finfish aquaculture in the region.
Components of the BEMPs can include:
- Monthly water quality sampling
- Annual/bi-annual surveys for seafloor fauna and chemistry, seagrass and deep reefs and inshore reefs
- Annual BEMP reports prepared and published each year that detail all environmental monitoring undertaken and the results of that monitoring
Annual Environmental Review reports are prepared each year by licence holders in some regions. These reports summarise all environmental monitoring undertaken and performance against environmental licence conditions for the preceding year.
Noise monitoring surveys can be required of industry in response to public complaints about marine finfish farms. EPA also conducts independent noise monitoring.
Freshwater Finfish Farms – general monitoring requirements
The environmental licence conditions for freshwater fish farms are being progressively updated by the EPA. All large farms that discharge to surface waters will be required to undertake regular water quality monitoring of physicochemical parameters such as dissolved oxygen, suspended solids and total and dissolved nutrients for farm intake waters, effluent discharges and downstream environment. In-stream biological monitoring of algae and macroinvertebrate communities for waterways that receive effluent discharges may also be required. Record keeping and reporting for stocking biomass, waste volumes and waste disposal processes will also be required.
Annual Environmental Review reports are also prepared for most freshwater fish farms.
Review of Regulatory Requirements for Marine Salmonid Aquaculture