Soft sediment environments include gravely, sandy, silty, muddy areas of the sea floor which are home to a variety of organisms including a wide variety of invertebrates (e.g. worms, crabs, shellfish), bottom dwelling fish and bacteria. The majority of salmon farms in Tasmania are located over soft sediment environments.
The release of un-eaten salmon feed, salmon faeces, and other nutrient rich organic matter (e.g. biofouling debris) into the water column occurs as a result of current marine salmon farming practices in Tasmania. Some of this organic matter is dissolved in the water column while some of it is in the form of particles which float in the water column, sinking to the sea floor (at varying rates depending on their size and water current speeds). The release of dissolved and particulate waste has the ability to interact with soft sediment environments in a number of ways:
The impacts of these interactions tend to be greatest immediately below actively farmed salmon cages, decreasing with distance from the farm. The magnitude of interactions depends on the intensity and management practices of farming, the environmental conditions at the farm site (e.g. depth of water below cages, the energy of the environment) and the sensitivity of the soft sediment ecosystem.
How can extra organic matter and sedimentation interact with soft sediment ecosystems?
For more detailed information on the interaction between salmon farming and soft sediment environments browse through our research outputs on our publications page.
