Massive Salmon Mortality Reported in Tasmania's Macquarie Harbour
New data reveals nearly 2,000 tonnes of salmon died in Macquarie Harbour over fifteen months.
1Significant Salmon Die-off Revealed
Newly released documents show that approximately 1,907 tonnes of farmed salmon perished in Tasmania's Macquarie Harbour between October 2024 and December 2025. This mortality data, obtained by the conservation group Environment Tasmania through a Right to Information request, highlights a 15-month period of significant fish losses within the region's aquaculture industry.
2Industry and Conservationist Perspectives
Environment Tasmania claims these losses represent roughly 15 percent of the maximum allowed haul. Conversely, Salmon Tasmania CEO John Whittington argues that weight-based metrics are misleading, asserting that mortality should be measured by the total number of individual fish. He maintains that some level of loss is inherent in all livestock farming.
3Regulatory Status and Licensing
The Environment Protection Authority currently regulates 10 salmon leases within the harbour. Although the environmental licences for the three operating companies expired nearly a year ago, they continue to function under pending renewal applications. The EPA is currently assessing environmental conditions before issuing any new, formalised operating licences for these sites.
4Oxygenation and Environmental Impact
The harbour faces severe environmental pressure, particularly regarding the endangered Maugean skate, which exists only in this specific habitat. To mitigate the impact of aquaculture, the EPA directed companies to supplement dissolved oxygen levels. The industry has reached the required target of 10.3 tonnes of oxygenation per day to offset farm operations.
5Disease and Operational Transparency
Industry representatives state that Macquarie Harbour remains free from the specific bacterial diseases that have caused mass mortalities in other Tasmanian salmon pens. Consequently, companies have not requested the use of the antibiotic florfenicol in this area. However, critics continue to demand greater transparency regarding disease management and overall operational mortality rates.
6Scientific Advisory Committee Findings
The state's Scientific Advisory Committee identified multiple intersecting threats to the Maugean skate, including declining dissolved oxygen levels and broader climate influences. These factors pose a high risk to the species' survival. The environment department is currently evaluating whether to officially declare the harbour a critical habitat for the endangered skate.
7Historical Context of Mortality
This recent data follows a previous disclosure showing 1,149 tonnes of salmon died in the harbour during a seven-month window between September 2023 and March 2024. While the EPA now publishes monthly state-wide mortality tonnage, specific location-based breakdowns remain limited, complicating efforts to track long-term health trends across different Tasmanian farming regions.
8Future Regulatory Outlook
The EPA continues to monitor water quality, with plans to publish data every six months to inform future regulatory decisions. The timeline for licence renewals remains uncertain, as it depends on the completion of ongoing scientific assessments. The outcome will likely balance the economic interests of the salmon industry against critical environmental protection.