The advice provided to the Tasmanian Government states that for the Maugean skate to be afforded the best possible chance of survival, impacts from salmonid aquaculture on dissolved oxygen concentrations in Macquarie Harbour must be “eliminated or significantly reduced”. The advice explicitly states that the fastest and simplest way to achieve this is by “significantly reducing fish biomass”.
The federal intervention comes at a critical moment when marine farming and environmental licenses for finfish farming in Macquarie Harbour expire on 30 November 2023.
Key Points:
- The advice identifies the highest priority is to improve dissolved oxygen concentration within Macquarie Harbour waters by 2024.
- It recognises the fastest and simplest way to ‘eliminate or significantly reduce’ the impacts of salmonid aquaculture on dissolved oxygen concentrations is by reducing fish biomass and feeding rates.
- This is described as an urgent priority that should be actioned before summer 2023/24.
- It also details other key actions including improving hydro-electric river regulation, potential mechanical reoxygenation, and a captive breeding program as urgent priorities.
- Longer-term priorities include improving the monitoring and regulation of water quality, and remediation of historical mining pollution, among others.
“The advice clearly lays the blame for poor water quality at the feet of the salmon industry. It also makes it abundantly clear that the science on this is rock solid, blowing industry efforts to say otherwise out of the water,” said Eloise Carr, Executive Director of the Australia Institute Tasmania.
“The federal government has told the Tasmanian Government to take the action needed to clean up Macquarie Harbour so the Maugean skate can survive. This is as clear a message as you’ll ever get from a government minister that this industry needs to get out of the harbour. Previous reductions have not improved dissolved oxygen levels – this is why the industry needs to go completely.
“The salmon industry has been saying the science isn’t clear, that more research is needed, but the Conservation Advice from the federal government blows that theory sky high. We know the key threat is poor water quality in the Harbour and that the primary cause is aquaculture. This is what the scientists say, what the Department of Environment says and what the Federal minister says.
“The question is now: what will the Tasmanian Government do in response? We think they have an obligation not to renew the licenses when they expire on 30 November this year.”
