The SSPO figures show a small decrease in the overall average monthly survivability for 2019, down to 98.6 per cent from 98.83 in 2018.
The fall was due to a range of environmental challenges experienced by a number of farms in the third and fourth quarters of the year, including planktonic blooms and increased water temperatures.
For more about how the Scottish salmon sector cares for its fish click here.
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 with 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 number of health management tools available to Scotland's fish farmers."
Farmed Salmon Mortality: What are the causes?
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 successfully 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.
Scotland continues to lead the aquaculture world in the reporting of farmed salmon survival data and in the sustained management of sea lice.
For more about Sea Lice management click here.
Scottish salmon sector investment in sea lice management more than doubled from 2015 to 2018, from £26 million to £61.7 million.
