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Seal care in three phases

After the intake the seal is taken to a quarantaine unit. Seals we take in do not stay in the same unit the whole time: we work with three different care phases. Below, we explain the phases to you.

Working at Sealcentre Pieterburen

Phase 1: intensive care

First, seals lie inside, in phase 1. This is where the rehabilitation of the seal begins. You can compare phase 1 with hospital intensive care. The patients here are still very sick and weak. So we have to keep a close eye on them!


The units in phase 1 can be completely sealed off from the outside world, and from each other. You can think of them as quarantines. We can close them if we want to prevent diseases from spreading from one seal to the others.

We can also control the temperature and light in these units. This keeps the seal warm and allows it to rest in the dark.

It is stressful for a seals to have many other seals around them, especially if they are is sick. This is why we never have more than two seals per unit at this stage. This also reduces the chances of transmitting diseases.

No swimming yet

In these units, we can put fences between the platform and the pool, so that the seal cannot reach the water. This is necessary because the patients here are still very weak. In the beginning, it is important that the seal rests and gains strength.

After a while, they will get stronger and may try to swim. At first, only for a few minutes. Does that go well? Then they are allowed to swim a little longer. Eventually, the gate stays open all day and the seal can decide for herself when to enter the water. The pools in phase 1 are small, as the seal care nurses need to be able to get the animals out of the water easily.


The seal care nuses and volunteers clean all units thoroughly every day. In phase 1, the walls, floors, fences and sink are scrubbed and disinfected every morning. The pool is also emptied, disinfected and refilled with clean water. Because the seals defecate and urinate a lot, it is very important that this is done daily.

Health checks

The vets and nurses keep checking how the seal is doing. This allows us to intervene immediately if something seems to be going wrong. Below you can see the checks that are carried out regularly.

Food and medicine

We feed the seals in phase 1 four times a day. The first feeding is at 07.00 in the morning. At first, the seals are not yet given fish by the seal care nurses. As they are not yet strong enough to digest a whole fish, we always start with a special porridge of ground salmon and water. This porridge contains many fats and important nutrients that the seal needs to gain strength. The seals are therefore usually given medicine in their food a few times a day.

After the first week, the seal is usually strong enough to start eating real fish. The seal care nurses feed the fish by hand, because most of the time the seal does not want to eat it by itself. We still give fish porridge twice a day, but the other two feedings consist of fish. Often, the seal is also allowed to swim briefly during cleaning and at feedings.

The better they get, the more fish they get. We try to make sure that the seal learns to retrieve the fish from the bath by itself. Seals that no longer get fish porridge at all will need some extra water in the beginning.

Did you know...

In the wild seals don't drink water? They live in the sea, so the water there is much salty to drink. Drinking seawater would be incredibly bad for them! Instead, seals get the moisture they need from the prey they eat.

Phase 2: recovery

Our vets decide when seals are ready to go outside for phase 2. They base this on the seal's weight, how well the animal eats, how long they can swim and on the seal's health in general. The animals have not been given fish porridge for a while and need a lot less medicine than in phase 1.


In phase 2, the seals are outside. They must therefore be strong enough to withstand bad weather. As they still need to gain some strength, the enclosures in phase 2 have a roof with heat lamps under which the seals can lie in bad weather or cold. If it is very hot in summer, we hang sprinklers on the fences so that the animals stay cool when they are resting.

More than two seals per enclosure can lie here. Because they have more space, seals can give each other space when they need it.

Swimming any time

Once outside, seals are allowed to swim all day. In phase 2, seals are already a lot stronger than in phase 1. Still, it is important that we can care for the seals on shore. The pools in phase 2 are therefore still small enough that we can get the animals out of the water quite easily. We do this by placing gates between the seals and the water. After treatment, they are allowed back into the pool.


Just like phase 1, the outdoor enclosures are cleaned daily. The fences and floors get a thorough cleaning every morning. The water is continuously cleaned by our filter system (just like in a swimming pool!) and once a week the entire pool is emptied, cleaned and refilled.

Health checks

In phase 2, it is no longer necessary to regularly take temperatures or check umbilical cords. However, we do weigh them every week and make sure they eat about the same amount every day.

Food and medicine

In phase 2, we feed the seals, herring three times a day. Not all seals eat independently yet. In this case, the seals are separated during feeding.

The animals that eat on their own stay in the pool where their fish is thrown in. The remaining animals are fed by hand on the side of the pool. If they still don't get enough fish, we have to feed them extra water.

The seals at this stage sometimes still need medicine. We put the pills in a herring or grind them up and give them with water. If a seal needs cream or eye drops, it is kept on the side of the pool for a while so it can take effect.

Phase 3: almost better

One more phase to go! In phase 3, seals eat independently and we no longer need to watch them so closely.

In all weathers

These enclosures no longer have canopies or heat lamps, so the seals have to lie outside in all weathers. This is not a bad thing, as there are no shelters or heat lamps in the Wadden Sea either. It does mean that the seals must already have a good layer of fat in this phase, especially in winter.

The pools in phase 3 are very large. Here we can no longer take the animals out of the water at every feeding, this is no longer necessary.


Of course, we also clean these enclosures every day. As in phase 2, the floor and fences are cleaned daily. The big pool is emptied at weighing time, so then the bath can also be scrubbed. Here too, the water is continuously cleaned by the system. 

Only food

The seals here no longer need medicine or extra water. We give them a large amount of fish twice a day, which they eat independently. The aim of phase 3 is therefore to gain good weight so that the seals have enough fat reserves when they are back in the wild.

Health checks

They no longer receive medication and health checks are often no longer necessary. However, the seals are still weighed every week. As it is very difficult to get the seals out of the water, we make sure they are all in the pool when we empty it. After a while, the animals lie on the bottom of an empty pool. This way we can catch them more easily.

More importantly, leave them alone

Apart from feeding and weighing, we leave the seals completely alone in phase 3. This allows them to get used to being alone as much as possible. Without people around them.

Back home

When the seals have had all the phases of seal care, they are ready to be returned to the wild. The vets decide when an animal is healthy enough to be released. When the time comes, the seals are loaded into release boxes and returned by boat to their home: UNESCO World Heritage Site the Wadden Sea. This remains special to us, a unique experience.