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FLS Delouser uses seawater at seawater temperature

Published 21 Mar 2023 (updated 29 Apr 2024) · 2 min read
Delousing at industrial fish farm

Quick information

  • Available

At a glance

  • Fast, effective delousing of salmon and trout
  • Mechanical system that promotes good fish welfare
  • Chemical-free and environment-friendly

FLS Delouser is a mechanical delousing solution for salmon and trout. The chemical-free system uses seawater at seawater temperature and has a high focus on fish welfare.

Sea lice are a major problem for producers of Atlantic salmon and trout, as they make the fish more prone to wounds, infections and fatality. The most widely used form of treatment involves delousing with chemicals, which can contaminate the fish as well as the surrounding ecosystem.

Furthermore, sea lice have begun to acquire resistance to the most common and effective delousing agents, causing them to become an even greater threat.

Effective and safe delousing system

Rather than using chemicals, the FLS Delouser flushes the fish through a vacuumated pipeline with seawater at seawater temperature. The pressure in the pipeline is low, resulting in fewer injuries and keeping the mortality rate very low. Moreover, the fish are in good enough condition to start eating right after delousing is completed.

The FLS Delouser removes the fish from a net-pen and releases them straight into a net-pen after treatment. Unlike many other mechanical delousing systems, the fish are not treated on deck where they are exposed to the air, fluctuating temperatures or harsh weather.

Fish being let go

Concrete benefits

The FLS Delouser is fast and effective. It can delouse 20 to 50 metric tons of fish per hour per line, depending on fish size and fish health, and remove 90 to 95 per cent of sea lice from the fish.

A modular system, the FLS Delouser has a user-friendly design and can be optimised to meet customer needs. High focus on fish welfare results in delousing with low mortality. Fish also have a better ability to eat right after delousing, compared with other mechanical systems.

The system can be fitted on different vessels, such as barges, service boats and well boats.

Moreover, because it is chemical-free, the FLS Delouser does not pollute the marine environment or lead to multidrug resistance among sea lice.

Market potential

Every market producing Atlantic salmon and trout faces challenges with sea lice to some extent. Production of salmon alone is expected to reach 4.7 million metric tons by the mid-2020s.

Norway accounts for over 50 per cent of the global market, but new markets are expected to emerge throughout the world in the coming decades, all in need of an effective, environmentally sound delousing solution.

Illustration of delousing system

Lars Georg Backer


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6520 FREI, Norway

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