SS1.01 Assessing Potential Environmental Impacts of Aquaculture
Date: Thursday, June 13, 2002
Time: 11:15:00 AM
Location: Lecture Theatre
VolkmanJK, CSIRO Marine Research, Hobart, Australia,
Parslow, J, , CSIRO Marine Research, Hobart, Australia,
Butler, E, C, CSIRO Marine Research, Hobart, Australia,
Blackburn, S, I, CSIRO Marine Research, Hobart, Australia,
Revill, A, T, CSIRO Marine Research, Hobart, Australia,
The marine cage farming of Atlantic salmon has grown rapidly in Tasmania, with most production occurring in the Huon Estuary, south of Hobart. Waste from fish cages is largely restricted to the sediment area beneath the cages, but organic matter contents in the estuarine sediments are very high and accumulate in summer when phytoplankton production is high. Lipid biomarkers and stable carbon and nitrogen isotope data show that in the upper reaches of the estuary the organic matter is mainly of terrestrial origin, but in the lower reaches it has a distinctive marine signature. A comprehensive three year environmental study of the estuary (see has determined the sources, distribution and cycling of nutrients (including those from finfish farming), and related algal dynamics to nutrients and physical parameters. Nitrogen distributions and algal production in the Huon Estuary waters under present-day conditions are supported primarily by nutrient inputs from coastal seawaters. However, modelling shows that were fish production to be significantly increased, nutrients from farms could fuel prolonged and more intensive algal blooms.