Salmon farming has come a long way since the fish were first grown commercially in cages in Norway in the 1960s. The industry has expanded rapidly in recent decades, with around 70% of salmon eaten around the world now coming from farms.disease among the fishMajor mortality events, involving the sudden deaths of millions of fish have been well documented, sometimes caused by disease outbreaks but also linked to warmer seas resulting from climate change.
To shed some light on these deaths, researchers looked at data from countries producing 92% of farmed salmon over the past decade.They found that the frequency of the biggest die-offs was rising over time for Norway, Canada and the UK.Norway has suffered significant losses from major salmon mortality eventsThe authors estimate that the potential maximum losses for any single mass mortality event are 5.14 million fish in Norway, 5.05 million in Canada and more than one million in the UK.
"In addition, production practices, and technology that is increasingly pushing production into riskier conditions and allowing for greater production per site may expose larger and larger populations of fish to conditions that cause mortalities." "Mortality is only one of many grave welfare concerns for farmed salmon," said Kirsty Jenkins, a policy officer at campaigners OneKind.
Some experts wonder if the industry can survive the increasing frequency of these mass die-offs in major production centres.