Salmon + Sea Lice: Here’s What You Need to Know

Learn why strict regulations ensure sea lice pose no environmental or food safety threat.

Sea lice is nothing new and poses absolutely no threat to food safety. It is simply a nuisance for the aquaculture industry.

Norway pioneered the development of responsible ocean salmon farming in the early1970’s and to this day, ranks among the world’s leading programs. Their secret?

Norway has depended on a combination of strict health regulations, close safety monitoring and continuous work to develop their aquaculture industry. Combining hard-earned experience and advanced technology, the industry is able to monitor and promote healthy fish growth and food safety at every step.

When it comes to sea lice, Norwegian authorities have a strict limit of 0.5 sea lice per salmon and nearly all salmon farms in Norway are well within these limits. Fish farmers must count sea lice on a weekly basis and report back to the authorities. The authorities and the industry itself use this data for deciding and coordinating the best strategies to keep the lice count as low as possible.

There are several factors that contribute to the presence of sea lice such as water temperature and salinity (water density). As sea lice depend on salmon to survive, their numbers often coincide with the numbers of fish. An increase in the number of farming sites may therefore lead to an increase in the number of sea lice.

The Norwegian seafood industry has increased its focus on non-chemical and mechanical treatment methods to reduce the presence of sea lice in their salmon farms. These approaches are important for future success in controlling sea lice.

Antibiotics are NOT used to prevent the proliferation of sea lice as this is not a bacterial disease. On occasion, veterinary medicines may be used to limit sea lice and safeguard the health of the fish. With that said, Norwegian Authorities have reported a decline in the use of medical treatments in the fight against sea lice.

The Norwegian industry mostly relies on non-medicinal methods such as closed or semi-closed aquaculture systems, lice skirts and covers that prevent the lice from entering the fish farms. Special types of “cleaner fish” and lumpfish are also used, as well as a patent method using only water. 

Sea lice is a natural occurrence and Norway will continue to explore new ways to keep the numbers at a minimum.