Tasmanian salmon mortalities rose in 2025 amid higher water temperatures
At least four million Atlantic salmon died prematurely at Tasmanian fish farms in 2025, according to data published by the state’s Environmental Protection Authority.
The data show that around 500,000 fish died during November and December, coinciding with rising ocean temperatures. Total losses for the year amounted to 20,133 tonnes of salmon that died before processing, with more than 2,500 tonnes recorded in the final three months of the year.
In December alone, average daily mortalities exceeded 40 tonnes, nearly three times the monthly average recorded between July and October, the EPA figures show.
Scientific studies have found that Atlantic salmon performance deteriorates as water temperatures approach 18°C, with higher temperatures associated with lower oxygen availability, reduced appetite, increased disease susceptibility, and organ stress.
Tasmania’s marine salmon producers harvested close to 68,000 tonnes of gutted salmon for human consumption during the 2024–25 financial year.
The EPA data were released on Friday.