Fish health

Facts about fish health

Fish farming is one of the most effective ways to produce nutritional food.

It is becoming ever more important at a time of expansive population growth, increased need for sustainable food production and a need for increased performance of marine proteins in the global diet. Profitable and sustainable production will also create new requirements for the health of farmed fish.


Facts about fish farming and health

Salmon and trout farming represent extremely effective forms of food production. Fish only need a fraction of the feed required for other "livestock" to produce a corresponding amount of meat. But production is not without its challenges.

A substantial proportion of farmed fish are lost before they can be slaughtered. There are many causes for this. Some of the wastage is due to different diseases and the handling of salmon lice, and it also appears that some fish die with no preceding illness. This may mean that these fish haven't been able to cope with the stresses they are exposed to on a daily basis.

Some key figures from 2015: Salmon Rainbow trout
Number of individual fish released to the sea 287 mill. 15.7 mill.
Number of localities with permits 974 mill

214 mill

This means financial challenges for the industry through less production, time and resources. Just as important are the consequences for animal welfare and the reputation of the industry. For all fish farmers, focusing on fish health and fish welfare is necessary for sustainable production, and a good reputation for salmon as an international brand.


Can we increase production

Can we increase production five-fold?

SINTEF and collaboration partners reported in 2012 on the possibility of increasing production of Norwegian farmed fish five-fold by 2050. Such growth is desirable from the perspective of the authorities from both a climate perspective and with regard to the economic potential this involves, but this vision has been put on hold.

Growth on this scale means annual growth of between 4 and 5 per cent. However, the reality is that the last few years have seen growth stagnate, and at the end of April 2016, the biomass in the sea was 4 per cent lower that at the same time the year before. This is to be seen in connection with the profound challenges the industry has with salmon lice.

Fish health is crucial

To protect wild salmon against increased pressure of infection from aquaculture, the authorities have introduced regulations regarding how many lice a fish farm can have. The fish must be treated if this number is exceeded, which causes stress and can result in increased mortality. Prevention of disease is therefore the key to achieving sustainable and profitable production of salmon with good animal welfare and the least possible use of medications. 

Fish health is a result of a number of factors such as hereditary factors, the environment, density, pressure of infection, and nutrition. The responsibility for healthy fish rests first and foremost with the fish farmer. But health professionals such as veterinarians and fish health biologists, and everyone involved aquaculture nutrition are important contributors to fish being as healthy as possible.

Two challenges

Before the number of concessions and the amount of fish can be increased, two key challenges connected with production have to be solved: wastage must be reduced and the number of salmon lice must be kept to an acceptable level to prevent increased infection pressure  for wild salmon.

How to avoid disease?

How to avoid disease?

Preventive health care is all about increasing awareness of health and providing the foundation for the most effective possible prevention of disease. By changing the environmental and living conditions, we can reduce the occurrence of risk factors. 

In order to achieve effective prevention of disease, it is important to work holistically with ongoing research and development regarding new vaccines, strategic breeding and optimisation of feeding.

If we manage to prevent infectious disease in just one fish farm, this will also in theory lead to less infection pressure on fish in surrounding cages and thereby reduce infection pressure overall. 

One example of preventive health care

To work preventively with health care is a dynamic process. Salmon farming is an industry in constant development. New challenges will emerge as the conditions surrounding fish change. New forms of farming and new diseases require that salmon must be continuously adapted to the new conditions.

One example is the growing proportion of large smolts that are being produced. Research indicates that larger smolt can better tackle the transition to the sea, but this requires increased knowledge regarding requirements with respect to the design, handling and environmental conditions in the hatcheries. This effects not just fish farmers, but is also a challenge for other participants in the industry.

BioMar contributes with a feed that is adapted to recirculation farms that are kinder to the living biofilters that are used for cleaning the water. We thereby contribute to keeping the living conditions the best they can be. 



Animal welfare

Animal welfare engages and is often a topic in media reports about the fish farming industry. Focusing on fish welfare is important, every fish is entitled to be looked after as best it can be, and it is easy to overlook the individual when 200,000 fish are swimming in the same cage.

What is animal welfare?

What is animal welfare?

Everyone can have their own opinion as to what constitutes good animal welfare, but to define it is not an easy thing to do.

The general perception is that animal welfare is good when the animal is in good health, can cope with its surroundings and can therefore behave normally.

The Bambi factor

Fish welfare has not been a great concern with traditional fishing. It was believed for a long time that fish cannot feel pain, and nor did they have the same need for protection as more traditional livestock.

  • A fish does not arouse the same warm feelings in people that a kitten does. Appearance lacks the "Bambi factor".
  • Nor do fish express pain in a way that we recognise.
  • We know that a dog is in pain when he or she whines, and that a child is hurt when he or she cries.

Through research, we now know that fish also feel pain, even though they do not express it in a way that we can easily perceive.


Fish welfare is regulated

Fish welfare is regulated

Fish have long been included in animal welfare legislation, but it was not until the new Norwegian Animal Welfare Act in 2010 that the law was adapted to cover farmed fish. Today, there are numerous laws and regulations that contribute to ensuring that fish are looked after as well as possible. 

The Norwegian Animal Welfare Act from 2010 establishes in an introductory paragraph that it also applies to fish.

  • It affirms that all animals have a right to be treated well despite their utility value. This gives every fish a value enshrined in law, regardless of the economic value it represents for the fish farmer and for society. 

The Regulation regarding Aquaculture is aimed directly at the fish farming industry. Its intention is to promote good health in farmed fish and ensure good welfare for them.

The regulation contains specific requirements with regard to farmed salmon, and ensures that the animal technicians and others who intend to work with farmed fish undergo a fish welfare course at least every five years in accordance with a system approved by the Norwegian Food Safety Authority. This ensures that those who come into contact with fish on a daily basis have basic skills in fish welfare.

  • This is in addition to the specific aforementioned regulations that ensure that fish are treated well at all stages of the journey from fjord to table. This is established in separate regulations that govern conditions during both transportation and slaughter.

The Norwegian Food Safety Authority has overall responsibility for ensuring that conditions concerning fish are satisfactory with respect to animal welfare.

  • The current laws and regulations can be found at
How do we measure?

How do we measure animal welfare?

It is easy to define animal welfare based on mortality, but this is not necessarily a good criterion. Not all fish experiencing poor animal welfare will die. Not all fish that die have experienced poor welfare. In order to determine whether fish are being cared for satisfactorily, we depend on being able to measure this.

We have our own protocols for setting animal welfare objectives.

  • For many species, there are very specific protocols that can be found at
  • There are no specific protocols designed for fish, but we have defined the animal welfare parameters.
  • These can be broadly divided into animal-based and resource-based welfare parameters.          

Animal welfare parameters

Animal-based welfare parameters are measured based on the animal and involve physiological measurements such as blood samples, stress hormone analysis, behaviour, morphology and health. In everyday activities, behaviour and health are the most accessible measurements that can be observed, and these are used most often as animal welfare goals.

Resource-based welfare parameters are measured in the surroundings and routines and involve amongst other things measuring the water environment, conditions involving feed and feeding, and other operating routines.

Extensive work is being carried out in many research environments to determine good, standardised methods to measure fish welfare.  Read more here

Cleaner fish & animal welfare

Cleaner fish and animal welfare

Cleaner fish, if they function well, are a good weapon in the battle against salmon lice. Understanding the conditions requied by cleaner fish hasproved to be challenging at times, when they were first used very little was known about how to provide a habitat that was benefical to their welfare, or a diet that met their nutritional requirements.   . This has changed as more knowledge has been gained and by improving the welfare of cleaner fish in the cages, we achieve more efficient cleaner fish with better survival rates and greater appetite for lice.

Cleaner fish are covered by animal welfare legislation on the same level as salmon.

  • Intensive research into their needs in terms of surroundings has produced results.
  • It is now common for cleaner fish to have access to somewhere to hide where they can stay in the cage and obtain their own feed.
  • It was commonly held long ago that they didn't need feed as they would only eat lice. We know now that access to somewhere to hide and feed are necessities for health and welfare, and makes them far more effective at feeding on lice.

Nevertheless, challenges remain regarding the welfare of cleaner fish, and different species of cleaner fish present different challenges. Wrasse continue to be obtained by capturing them live and transporting them to the farms. Many fish have to be transported long distances and some fish do not always survive the journey. 

The lumpfish is a species of cleaner fish that is currently increasingly farmed and experiences some problems in terms of disease. This is a form of farming in its initial stages and much research is being conducted to map out the specific needs of the lumpfish in an aquaculture context.

The myths about antibiotics

The myths about antibiotics

That farmed salmon are full of antibiotics is a myth that lives on. But it is not the case! in the 1980s, bacterial diseases were a problem in salmon farming, but effective vaccines were developed in the 1990s. This led to a considerable decrease in the occurrence of bacterial diseases.

  • The fact is, the fish farming industry currently accounts for about 1% of the use of antibiotics in Norway.
  • In comparison, meat and egg manufacturers use 14 % and 85 % is used in human treatments. 

The Norwegian Institute of Public Health monitors sales of antibiotics. In relation to biomass produced by farmed fish, the changes in the sale of antibacterial agents for the treatment of farmed fish are marginal and sales are very low.

The quantity of antibacterial agents that has been sold over recent years means that an estimated 0.5-1 per cent of fish were treated with an antibiotic.

Read more

This figure has been obtained from the Norwegian Veterinary Institute's annual report regarding the use of antibiotics in Norway.  This shows how the ratio between the amount of salmon produced and the use of antibiotics in the fish farming industry has developed since 1981 The green curve shows the amount of fish produced, while the blue bars show the use of antibiotics.