HARMFUL algal bloom incidents are a major problem for aquaculture, and can lead to the deaths of thousands of fish at a time.

Last year, for example, a HAB in Upper Loch Fyne led to large-scale mortalities at Scottish Salmon Company’s Quarry Point farm.

HABs are also a problem for the fish farming industry in Norway.The spring of 2019 saw the most serious algae problem for almost 30 years. It killed at least eight million salmon in the Nordland and Troms regions, leading to job losses, hitting communities hard and costing the industry hundreds of millions of kroner.

Farmed fish are particularly susceptible to HABs, since unlike their wild counterparts they are unable to swim away from toxic algae.

HABs are associated with warmer sea temperatures, and continuing global warming means toxic algae is likely to continue as a threat to sea life, wild and farmed.