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Looking into how salmon lice are spread between fish farms

Looking into how salmon lice are spread between fish farms

Published 18 September 2017

Chile’s problems with salmon lice in its fish farms are so great that the country is seeking help from its competitor, Norway.

The video demonstrates how a virus spreads from a fish farm in a region of Chile, based on simulations using the ocean model system SINMOD. The virus particles remain visible for four days, and the simulations are used to understand how ocean currents transport infectious materials between fish farm facilities.

Norway is the world's largest fish farming nation, and makes enormous profits from salmon due to low production costs. In Chile however, the situation is quite different. Ten years ago, the entire aquaculture industry was devastated by disease, and it has taken many years to re-establish itself. SINTEF was contacted five or six years ago and has since been working very closely with Chile.

"In Chile, many fish farms have been located very close to shore", explains Øyvind Knutsen, who is a researcher at SINTEF Ocean. "This makes it easier for disease to develop", he says.

While regulations in Norway are relatively strict, the Chilean authorities have permitted fish farms to be established more closely together. This has resulted in some "fire-fighting".

"We've recently been asked to carry out a new project involving a network analysis within a given area", says Knutsen. The aim is that SINTEF's data analyses will provide important answers to questions such as where the spread of infection is greatest, and what are the most efficient ways of locating production facilities in order to reduce the probability of disease", he says.

Researchers use advanced analytical software that simulates a "release" of lice into the ocean. They can then observe how the lice are carried by the currents.

"It's very costly for a facility to be inundated by too many lice, and then have to be deloused", says Knutsen. In the worst case, this may run to several hundred thousand Norwegian kroner. For this reason, there is a major focus on trying to get to grips with the salmon lice situation in Chile", he says.

Researcher Daniel Jimenez at the salmon technology institute Intesal is one of SINTEF's partners in Chile. He confirms that the industry needs help.

"The researchers at SINTEF have been very helpful, especially when it comes to modelling hydrodynamic conditions at various locations in Chile", he says. "The Chilean aquaculture industry is the second largest in the world, and its problems have far-reaching socio-economic implications for our country", says Jimenez.

– Have the Chilean authorities done anything to limit the spread of disease?

– Following the ISA outbreak in 2008, the authorities have introduced many new regulations with the aim of improving fish health at the facilities", says Jimenez. "For example, we now operate with the same delousing procedures as in Norway", he says.

The industry in both Chile and Norway is experiencing problems linked to salmon lice and the spread of disease, and the environmental challenges it faces will only increase in the years ahead. SINTEF hopes that the aquaculture sector will direct even greater focus on sustainability.

"We already have a close working relationship with the aquaculture sector, but have not carried out the same type of sustainability studies and network analyses in Norway as we have in Chile", says Knutsen. "There's no doubt that Norwegian producers would benefit from analyses of this type, especially in connection with the spread of infections and environmental issues", he says.

Research Scientist