Reactive lice management has proven unsuccessful, and it is clear that prevention is the most promising path forward. One such method involves barrier technologies, such as lice shielding skirts and snorkel cages. The core concept behind these solutions is to establish a physical barrier that directs seawater around the cage, preventing direct contact between sea lice in the upper water layers and the fish inside the cage. While this reduces lice levels, such measures can also present challenges regarding fish health, welfare, and production performance.
Barrier technologies such as lice skirts have been used in the industry for well over a decade, though with varying degrees of effectiveness and associated challenges. This project aims to examine some of the challenges linked to the use of these barrier technologies, seeking to fill critical knowledge gaps through a combination of data collection at commercial sites and robust, controlled experimental trials.
The project is led by Tina Oldham at the Norwegian Institute of Marine Research. SINTEF will contribute by investigating how the physical environment interacts with lice skirts, specifically focusing on waves and density gradients that can affect water exchange within the cage.
To study the interaction between density gradients and lice skirts, experiments using the dye fluorescein will be conducted in meso-scale cages equipped with lice skirts, both with and without flow-generating systems such as the "Midtnorsk ringen." By studying the movement of the dye and changes in concentration over time, the study aims to investigate how the positioning of a density gradient in the water column can influence the effect of aeration systems and changes in water exchange within the pen.