The 2019 results, which have just been published by the Scottish Salmon Producers Organisation (SSPO), show a slight decrease on the 2018 figure of 98.83 per cent. This has been attributed to "environmental challenges" including planktonic blooms and increased water temperatures experienced by a number of farms in the third and fourth quarters of the year.
These directly and indirectly impacted on the health of some fish, with the largest reported cause of premature mortality among stocks resulting from gill health issues.
Hamish Macdonell, director of strategic engagement for the SSPO, said: “The Scottish salmon farming sector continues to invest and innovate in the management of such challenges. Fish health and welfare will always be our members’ top priority.
“There are a number of initiatives underway to increase the health management toolbox available to Scotland’s fish farmers.
“These are being complemented by focused research into understanding the impacts of recent environmental challenges, the Scottish 10-year Farmed Fish Health Framework and increased sector-wide information sharing.”
Scotland will host the next Gill Health Initiative (GHI) meeting in April, with representatives from Chile, Norway, Faroes and Ireland expected to attend alongside their Scottish salmon farming counterparts.
Sea lice averages for 2019 were 0.54 adult female lice per salmon, up slightly from a seven year low in 2018 of 0.46. The Scottish salmon sector is continuing to pursue its prevention over cure strategy with regards to the management of sea lice, with medicinal spending falling as the increasing deployment of innovations such as cleaner fish and mechanical treatments.