Project number: 2004-074
Project Status:
Completed
Budget expenditure: $1,101,828.00
Principal Investigator: John K. Volkman
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 29 Jun 2004 - 30 Jun 2008
Contact:
FRDC

Need

The salmonid aquaculture industry depends on a healthy and suitable marine environment to maintain production and profitability. Over recent years, the industry has faced a number of environmental challenges, including algal blooms, jellyfish swarms, warm waters and high salinities. Salmon farms remain a significant point source of nutrients into the marine environment. While stocking densities in Tasmania are generally lower than overseas, and expansion of the industry is currently curtailed, it is still important to establish a carrying capacity which fosters a healthy and productive industry and protects marine environmental values.

Evaluation of this combination of issues and risks constitutes a significant scientific challenge. System-wide environmental effects such as the frequency and composition of phytoplankton blooms and jellyfish swarms, and possible effects on benthic communities may affect industry production and profitability. Equally, regulators and the public need assurance that marine ecosystems will not undergo unacceptable environmental change as industry develops. Industry and managers require a capability to resolve and predict environmental response to changes in offshore ocean inputs, changes in catchment loads, and effects of the industry itself. Advances in observation technologies, in scientific understanding, and in modelling capability are needed to underpin both long-term planning and short-term operational decisions. The goal here is for the CRC to work with industry and regultors to provide an environmental information and prediction system which allows each to manage environmental risk.

DPIWE has expressed a particular need to understand nutrient budgets in salmon-growing areas to assess how many fish can be grown. Salmon farmers have expressed a specific industry need for early warning of the advent of a phytoplankton bloom, and early warning of the likely level of threat of the bloom. Within the confines of the budget and logistical constraints we will attempt to meet both needs.

Objectives

1. 1. Identification, characterisation and modelling of the key oceanographic and ecological features of the Huon Estuary and D'Entrecasteaux Channel and how these may affect or limit salmon cage farming, together with an assessment of possible industry responses.
2. Inventory of the sources of nutrients in this region, including those from salmon farms, their spatial and temporal variation, nutrient cycling, and impacts on pelagic and benthic production.
3. Definition of the factors driving the phytoplankton ecology of this region, especially interactions among phytoplankton and zooplankton (including jellyfish)
4. Determination of the role of carbon remineralisation in sediments with nutrient release into the water column in relation to the varying spatial and temporal environmental conditions
5. Design of a new monitoring system and adaptive management strategy for use by industry and DPIWE together with definition of associated indicators and standards

Final report

Related research

Environment
PROJECT NUMBER • 2023-087
PROJECT STATUS:
CURRENT

Macquarie Harbour oxygenation trial

1. Develop plume model and run scenarios to inform injection depth, flow volume, concentration, and distribution of injection points for oxygenation trials.
ORGANISATION:
University of Tasmania
Industry
Environment