Tasmanian Salmon Farms Face Mass Deaths in 2025 Amid Rising Temperatures

At least 4 million salmon died prematurely at Tasmanian fish farms in 2025. Data from the state’s Environmental Protection Authority (EPA) indicates approximately 500,000 fish deaths occurred in November and December alone, coinciding with increasing ocean temperatures.

Scientific studies show Atlantic salmon are negatively impacted when ocean temperatures approach 18C. Higher temperatures result in less oxygenated water, liver and kidney damage, reduced appetite, and increased susceptibility to disease for the salmon.

Escalating Losses in Tonnes

More than 2,500 tonnes of salmon died in the final three months of 2025. The total death toll for the year reached 20,133 tonnes lost before processing, according to EPA data released on Friday afternoon. December saw over 40 tonnes of salmon die prematurely each day, nearly triple the monthly average observed from July to October.

Expert Warns of Unsuitable Waters

Stewart Frusher, a retired professor from the Institute for Marine and Antarctic Studies at the University of Tasmania, commented on the escalating mortality.

The increase in salmon deaths in December suggests potential challenges for upcoming months.

He further noted that waters in south-eastern Tasmania may not be suitable for salmon farming.

Welfare Act Questioned Amid Lack of Action

Tasmanian companies produced nearly 68,000 tonnes of gutted salmon for public consumption in 2024-25. The state’s Animal Welfare Act mandates that owners:

"Must not use a method of management of the animal or group which is reasonably likely to result in unreasonable and unjustifiable pain or suffering to the animal or an animal in the group."

Frusher observed that despite RSPCA's position that salmon experience pain, no apparent regulatory action had been taken regarding the mass salmon deaths.

Norway's Strict Penalties Provide Contrast

In Norway, mass fish deaths at salmon farms can lead to significant fines. In November 2025, the Norwegian Food Safety Authority fined aquaculture company Salaks 1.86 million kroner (A$286,000) for breaching fish welfare standards, which resulted in the deaths of about 106,000 salmon. Later that month, another company, Tombre, was fined for the deaths of 132,000 salmon.

Calls for Stronger Regulatory Deterrents

Jess Coughlan, senior campaigner at Environment Tasmania, stated that the absence of fines provides little incentive for the salmon industry to prevent mass deaths.

She suggested that penalties, similar to those in Norway, are necessary to deter current mortality rates from becoming normalized and to re-emphasize animal welfare within the industry.

Salmon Tasmania, representing the state’s three marine salmon producers, did not respond when asked for comment on calls for substantial fines for mass fish deaths.