The cleaning efficacy of lumpfish (Cyclopterus lumpus L.) in Faroese salmon (Salmo salar L.) farming pens in relation to lumpfish size and seasonality

This is convenient knowledge for implementation in the sea lice strategies of farming sites using lumpfish as cleaner fish in general, but especially in farming areas with large seasonal variations in the zooplankton abundance such as in the Faroes. The high occurrence of empty stomachs in small lumpfish highlights the necessity to adapt husbandry in the first period post lumpfish deployment, especially when the opportunity for naturally occurring food is sparse. Furthermore, our findings of biofouling having a positive influence on the grazing efficacy of lumpfish indicate that net cleaning might have a negative influence on lumpfish grazing efficacy.