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Every year, Bea and Marga observe all seals coming into the Dollard area. Since 2015, data has been gathered on over 400 seals (mothers and pups). The insights from this research are invaluable. On this page you can meet the team, learn about the methodologies used and discover key insights.

gewone zeehond moeder en pup dollard

Ongoing research

The research project in the Dollard started in 2015. Every day at high tide, seal mothers gather with their pups at the bottom of the dike in the Dollard. This is where they come to rest, eat and sunbathe. Which makes it a perfect research location. At a great distance, behind the observation wall and in utmost peace and quiet, our marine biologists Beatriz Rapado-Tamarit (Bea) and Margarita Méndez Aróstegui (Marga) and their team study the behaviour of seal mothers and pups in the wild every year.

Veldonderzoek - observatiemuur in de Dollard

We share our knowledge

The results give us insight into how wild seals behave. But also how the ecosystem, which we as humans share with the seals, is doing. As well as how we can prevent seals from getting into trouble. We share all of these results with our colleagues around the world, so that it also benefits seals and the sea in other places. For example, the research results have helped to ensure that 

Initial insights

One of the most important things we have found out is how long a seal pup can be on their own, without it meaning they've lost their mother. These results have directly influenced the way we work. Want to know what else we learned? seal guards and strict observation rules are in place nationwide today - and pups are taken in less often. A fantastic development!

Want to know what we've learnt? Click on the button below!

Meet the team


Beatriz Rapado-Tamarit

Research topic: seal mothers don't let just their own pup suckle

"Hello, I'm Bea! I'm from Spain, where I studied Evolutionary Biology and Systematics. As a child, I always wanted to work with animals, and dreamed of being able to talk to animals. Later, I became very interested in animal behaviour. Now I am a behavioural scientist and working on my PhD at the University of Groningen."

Margarita Méndez Aróstegui


Research topic: is a seal pup on their own really an orphan?

"Hello, my name is Marga! I am originally from the south of Spain. In Barcelona, I studied Biodiversity and Nature Conservation. Nowadays I'm doing a PhD at the University of Groningen. I have always wanted to work with marine mammals and I really like wildlife centres. We don't have seals in Spain, so I wanted to learn more about them here."


Research team

Bea and Marga do not work on their own. They get help from volunteers every year. The volunteers come from all over the world, often with previous experience in the field of ecology or veterinary medicine. For example, they study Marine Biology or are working in a wildlife centre. Helping out during the Dollard research offers them a new experience and a different way of working. Without them, this research would not be possible.

Veldonderzoek - observatiemuur in de Dollard

Our methods

How do you recognise seals?

To study seals individually, we need to be able to recognise them. We do this using the spots on their fur. Each seal's spot pattern is unique. You can compare this to a fingerprint. Our research team does this on seals in the wild. At a safe distance, with photo identification.

Field research

For the field research on seal mother and pups, our team uses the tides every day to observe their behaviour. The study runs from late May to mid-July. During this period, our team is ready to observe behind the observation wall in the Dollard every day. You can read exactly how they work, and what it takes, here.

Zeehond - moeder en pup zogen

Onze onderzoeksvragen

Philopatry in seals

Sometimes animals return to their birth area to give birth to their own young. This is called site fidelity. Researchers Bea and Marga look into whether seals show this behaviour as well and what the reasons are for this. 

Upbringing by seal mothers

Each animal species raises their young differently. An elephant, for example, may stay with their mother until adulthood. Seal mothers usually leave their pups after only 3 weeks. Interestingly, during those weeks they also milk other pups. We investigate why they do this.