How useful is the lice skirt?

In a project that has just been completed (see FHF #901453 Norwegian language), Aquamedic and 4 partners have carried out this field study to quantify the advantages and disadvantages of using the Midt-Norsk-Ring together with use of the skirt. The project has done research of the effect of using skirts against lice impact and attempted to quantify biological benefits or possible disadvantages (primarily related to the aquatic environment at the top of the net cages) by simultaneously using the Midt-Norsk-Ring.

In two marine sites with net pens operated both with and without skirts and Midt-Norsk-Ring, the louse settlement was generally very low for most part of the observation period, with little to no observed shielding effect of skirts against settlement of louse larvae. However, one of the sites experienced up to 50% reduced larvae settlement in net pens with Midt-Norsk-Ring following a relatively short mid-summer period with massive influx of copepodids. No such clear effect was, however, seen in a second site that experienced a much lower influx of copepodids during the same period.