At least 4 million salmon died prematurely at Tasmanian fish farms in 2025, with new data from the state’s Environmental Protection Authority (EPA) suggesting about 500,000 fish died in November and December as ocean temperatures warmed.
Scientific studies indicate Atlantic salmon are adversely affected when ocean temperatures approach 18C. At higher temperatures, salmon encounter less oxygenated water, suffer from liver and kidney damage, have less appetite and become more vulnerable to disease.
