Combating sea lice while preserving the environment

Av Sven Ove Bakke – Publisert 19. August 2019

The salmon louse is a huge problem for the aquaculture industry. Fighting lice has often required chemicals and other environmental hazards. With a new innovative sea lice skirt solution, Grieg Seafood has come much closer to the dream scenario of eco-friendly delousing.

Norwegian salmon export is big business. An all-time high was reached in 2018, with Norwegian fish farming companies exporting salmon for approximately 6.5 billion euros.

But even though markets are embracing the pink gold of the cold seas, the salmon louse is a constant threat. In a fully-packed fish farming cage, the louse can create serious havoc – for the fish itself, for the profitability of the fish farmer and in the end for the environment, if delousing is done the old-fashioned way.

Earlier this year, Institute of Marine Research estimated that salmon or sea louse potentially creates losses of more than half a billion euros in various delousing efforts including cost of chemicals and decreased value of the fish itself. Professor Øystein Evensen at Norwegian University of Life Sciences was quoted by financial news website that this serious problem threatens the growth possibilities for the industry at large:

– Looking at the numbers, the annual 1.2 million tonnes tells a story about stagnation. This number cannot grow unless the industry gets the problem of salmon louse under control.

Half of the fish cages in Øksfjorden in Northern Norway are equipped with Protan's sea lice skirts. (Photo: Protan)

Delousing and cleaning cages with infected fish is a costly and time-consuming task. The continuous effort to delouse will stress the salmon and is bad for their general living conditions. A sea lice skirt around the cage eliminates some of the delousing challenges, but with Protan’s and Brisk Safety’s innovative take on the construction of the skirts, the delousing process can be even more eco-friendly.

The salmon louse thrives in the water closest to the surface. Mounting a protective skirt around the cage that goes 10 metres deep creates a very effective protective barrier against the lice.

Protan has a long tradition of inventive use of technical textiles and PVC membranes. From previous experience with aquaculture products, we knew that the rough conditions of Norwegian waters would cause traditional sea lice skirts to move and float upwards and thus losing their intended function. This was the background for a new and innovative approach.

The indigenous solution is to create pockets at the bottom part of the skirt. The pockets will be filled with seawater, which will anchor or stabilize the skirt just like a sinker. Wind and waves will in fact increase the stability of the installation.

The pockets keep the skirt in place. The fish farmer will not need to be concerned that lice will enter the cage in rough weather.

Thus far, major aquaculture player Grieg Seafood has replaced half of its fish farming cages in Øksfjord in Finnmark with the improved sea lice skirts. Production manager Vidar Aamo Nikolaisen says that Grieg Seafood plans to make further tests in even more stormy and weather-beaten locations in Finnmark, the northernmost region of Norway.

Even though pockets on skirts might sound like a simple idea after all, there is another major takeaway, which has attracted industry leaders like Grieg Seafood and Salmar to our products and solution: the skirts are made of 100 percent recyclable material.

A sea lice skirt under production. (Photo: Protan)

SINTEF, the leading independent research institute in Norway, has estimated that the aquaculture industry generates as much as 29,000 tonnes of plastic waste annually. Other estimates are calculating that 80 percent of all plastic waste in northern waters stems from aquaculture businesses. Converting to sea lice skirts made of 100 percent recyclable PVC material will be a substantial contribution to the fight against plastic waste offshore and also eliminate microplastic pollution.

The customer simply returns the used sea lice skirts to us. A typical recycling process for the skirts would be to grind it and reuse it in some of our other products, such as roofing materials. We are talking about a lifetime of possibly more than 60 years.

This is great news for an industry in search of more sustainable practices. The end customer is gradually being more concerned about the origins of the products they buy in the supermarket and under which conditions the salmon have been raised.

Production manager Vidar Aamo Nikolaisen at Grieg Seafood has sustainability concerns high up on his list of priorities.

– I hope and believe recyclable and eco-friendly solutions for fish farming, like Protan’s sea lice skirts, will be a future norm for our industry.

More references

Grieg Seafood voices sustainability concerns – chooses environmental-friendly PVC

How can we reduce the critical amount of plastic waste in fish farming? World leading aquaculture company Grieg Seafood has shown the way forward by pioneering sustainable and eco-friendly solutions. A great example is artificial seaweed made from 100 percent recyclable and drinking water approved PVC.