Provide the context of the project that demonstrates the reason for doing the work and its relevance to IMAS research priorities. The statement should clearly illustrate the relationship between this proposal, work done previously and other work in progress. Bear in mind that this will be used in the description of the project on the Web.
The Salmon industry in Tasmania seeks to double production by 2030, but achieving this will require both new farm production approaches and expansion into new areas. Maintaining high environmental performance (a priority for both the industry and its regulators) requires an understanding of how farming in new areas might affect the environment. To ensure that management remains best practice, and farms continue to be efficient and sustainable, a reliable understanding of the local and broader scale impacts and potential interactions with other resource users are required. A research project funded by the FRDC has just commenced that will undertake a mix of modelling, field based studies and targeted experiments, with a view to characterising the extent of farming impact and identifying indicators that can be used to monitor for near and far-field impacts. The identification of suitable assessment sites will largely be based on modelling outputs, with targeted experimental studies then located at sites to assess environmental conditions before and after farming. This study will be undertaken in all of the current salmon farming regions (Lower Huon/ Channel, Storm Bay, Macquarie Harbour).
Dispersion modelling will be used to link off-site assessments to local scale studies, specifically to identify exposure to nutrients and sediments from fish farms. Ultimately, the deposition and dispersion models will provide an important predictive tool for determining risk to the ecology of soft sediment and reef habitats in areas where salmon farming occurs.
Dispersion modelling is used to identify the "footprint" of the farms either in terms of actual sediment deposition or the extent of nutrient dispersion. This estimate relies on accurate evaluation of the initial nutrient content of the feed/ waste material source. The leaching and degradation rates in these models are currently based on values from studies undertaken over 10 years ago and, whilst potentially quite conservative, these values would benefit from validation based on a more accurate and recent assessment based on diets currently in use.