This is the damning truth behind salmon lice in salmon farming
When you think of lice, you undoubtedly think of those times when your classmate’s mother went through your hair at primary school. But lice don’t necessarily only nest in hair. They can also be found, for example, on the bare, smooth skin of salmon. Salmon lice are what these little creatures are called. The truth behind salmon lice will really make you scratch your head…
Salmon lice are parasites that attach themselves to the skin, fins and gills of salmon. They feed on the salmon’s mucus, skin and sometimes blood. This weakens the fish and makes them much more susceptible to infections. Salmon with salmon lice therefore often have sores on their skin.
Salmon lice in the wild
Salmon lice occur in both wild salmon, which swim freely in the sea, and farmed salmon. In the wild, salmon lice mainly live on adult salmon. The parasites reproduce in salt water, after which the larvae are released into the environment. When salmon return to fresh water, the salmon lice die. The parasite cannot survive in that type of water. This natural pattern keeps the number of parasites in balance.
Problems caused by salmon farming
However, this balance has been seriously disrupted by salmon farming. Salmon farms cause major problems for both farmed salmon and salmon lice. For instance, these farms are almost always located in coastal areas with salt water. As a result, salmon lice are constantly present in the area. Salmon lice can spread incredibly easily and quickly there; huge numbers of salmon swim in cages. Wild salmon swimming past the cages can also become infected with salmon lice. You may remember from the past how easily lice jump from one person to another (which is why your mother always panicked so much). A vicious circle, in other words.
High mortality rate
Salmon lice are not dangerous to humans. But the consequences for salmon are enormous. The lice cause a tremendous amount of damage to the salmon’s skin, resulting in sores and scratches. These carry a high risk of infection. Moreover, salmon lice are extremely stressful – especially when salmon are swimming in a large cage with countless other salmon. It’s a bit of survival of the fittest in such cages. Many salmon infected with salmon lice therefore do not survive. The mortality rate among farmed salmon is consequently extremely high: 1 in 5 salmon die.
Controversial control methods
Salmon lice have been and are controlled in various ways. In the past, all kinds of chemical treatments were mainly added to the water. They were not very good for nature, so you hardly ever see this nowadays. Another method is enough to send shivers down your spine. For a long time, salmon lice were controlled by throwing the salmon into a tank of warm water. You may be thinking: ‘isn’t that nice’? But no, salmon actually prefer cold water. Warm water causes them an enormous amount of pain and stress.
Stress!
Research shows that salmon even had to be euthanised after spending 5 minutes in a tank of water at 28 degrees Celsius, because they were under so much stress. At salmon farms, they spent ‘only’ 30 seconds in such a tank. However, that was already long enough to trigger an enormous stress response. Fortunately, you hardly ever see this controversial method anymore.
What can you do as a salmon lover?
Nowadays, other methods are often used. Such as laser technologies, in which lasers detect salmon lice on the skin and then destroy them. Salmon are also sometimes placed in closed or semi-closed farming systems. These make the salmon less accessible to salmon lice. In the industry, solutions that are also as cost-efficient as possible will in any case (almost) always be sought.
The best thing you can do as a salmon lover? Always choose certified salmon, for example with the ASC certification (Aquaculture Stewardship Council). This quality mark ‘aims to reduce the impact of fish farming on the environment and contribute to responsible fish production’ (according to Het Voedingscentrum). If in doubt, ask the fishmonger for more information.
Oh, and be extra careful when buying salmon at the supermarket. You’re often being ripped off. In this case, cheap is truly not better than expensive!
Also read:
- This is how you defrost salmon
- You can hardly mess this up: the easiest (and most beautiful) oven-baked salmon
- Recipe: Jamie Oliver’s crispy salmon tacos
Sources: Keuringsdienst van Waarde, Quest, ASC Aqua, Het Voedingscentrum
