String jellyfish skirt

We have developed an effective and user-friendly skirt solution to protect against string jellyfish, specifically designed with a 15-meter depth and easily mountable directly on the cage as a contingency measure. The skirt is made of 100% high-permeability mesh, which allows continuous water flow. This maintains proper oxygen levels inside the cage while still offering effective protection against string jellyfish.

What makes our solution unique is that the skirt is stored in a PVC pocket attached directly to the cage. This ensures it never interferes with daily operations. When needed, the skirt can be quickly and easily deployed by pulling a rope, causing it to drop to full depth and provide immediate protection. When protection is no longer required, the skirt can be easily hoisted back up and quickly repacked into the PVC pocket.

This practical and innovative solution provides day-to-day security, reduces the risk of production losses, and supports strong fish welfare.

In a December 2023 article from iLaks.no, Lars Helge Stien (Research Director in Animal Welfare) shared that the Institute of Marine Research is conducting a case study in collaboration with Mowi. They are monitoring the presence of string jellyfish at two empty cages — one with an 8-meter lice skirt, and one without a skirt.

Although string jellyfish are found at various depths, the study so far suggests that skirts can be effective: 75% of jellyfish observations near the cages were at depths greater than 15 meters, and 63% at depths over 10 meters.

According to Stien, significantly fewer string jellyfish were observed in the cage equipped with a skirt.