A brief history: from near-extinction to recovery
For centuries seals in the Netherlands were treated as wild commodity: their pelts were traded, their blubber rendered to oil, and the remains used as livestock feed. The combination of intensive hunting, disturbance and water pollution dropped the common seal population in the Waddenzee in the 1950s and 1960s to only a few hundred. The grey seal had vanished from the Netherlands by then: the last documented Dutch grey seal dated to centuries earlier, and targeted hunting had wiped the species from the North Sea coast.
The turning point came in two steps. In 1961 hunting was banned in the Delta; a year later — in 1962 — the Waddenzee followed. From that point the population could begin to recover, slowly. Around 1980 the first grey seals returned from British and Scottish colonies; in 1985 a grey seal pup was born here for the first time in centuries — on a Waddenzee sandbar. Today the Dutch Waddenzee holds about 7,800 grey seals (2024 count), and de Richel, between Vlieland and Terschelling, is their main nursery.
The legal layers of protection
Seals in the Netherlands fall under several overlapping protection regimes. Together they form a robust safety net:
Nature Protection Law (Wnb / Omgevingswet)
Both the common and grey seal are protected species under Dutch nature law (since 2024 part of the Environmental Act). This means it is forbidden to kill, capture, deliberately disturb them, or damage their resting and breeding sites. Anyone with a reason to do so anyway — such as a rehabilitation centre collecting a stranded pup — needs an exemption.
Natura 2000
The Waddenzee, the Voordelta, the Oosterschelde and the Westerschelde are all Natura 2000 sites: part of the European network of protected nature areas under the Habitats and Birds Directives. The Habitats Directive explicitly lists both seal species, with the common seal in Annex II (requiring special areas of conservation). In practice this translates to zoning, restrictions on shipping and fishing, and seasonal access rules at nursery sites.
International treaties
The Netherlands is party to several treaties that further protect the seals. The most important is the Wadden Sea Seals Agreement (1991, with extensions running to 2026) under the Bonn Convention — a cooperation between the Netherlands, Germany and Denmark. It mandates annual coordinated counts, joint research and aligned policy across the entire Wadden Sea ecosystem — seals don't respect national borders.
The Seal Agreement (2020)
In 2020 the Dutch rehabilitation and coastal partners signed the Zeehondenakkoord: a joint framework between the national government, provinces, rehab centres, nature management organisations and scientists. It starts from one core idea: the seal is a wild animal and belongs in nature. Only when an animal truly needs help may an intervention happen — and then only by a trained seal warden.
Three key points:
- Members of the public may no longer touch or move seals. If you find one, keep your distance and call a warden.
- Rehabilitation only when truly necessary. A weaned, healthy pup belongs in the sea, not in a tank. The number of admissions has dropped substantially since.
- A single protocol followed by all centres (Pieterburen, Ecomare, A Seal, and smaller partners).
The agreement has been controversial: some centres argued the bar for intervention was set too high. But there is broad scientific support for the premise that unnecessary rehabilitation harms both welfare and the wild learning behaviour that lets young seals survive. Read more at rehab.
The role of seal wardens
In the post-agreement Netherlands, the seal warden is a central figure. Wardens are trained by recognised rehab centres and the authorities; they assess on the spot whether an animal is resting, independent, or truly in need of help. Wardens — alongside vets — are the only ones allowed to move or collect a seal. They log sightings, coordinate with the reporting line, and call in police or rangers where needed to prevent disturbance. How to call a warden and what such a visit involves is on seal warden.
What we protect them from
Protection isn't an abstract policy; it's an answer to specific threats. For the Dutch seal these are:
- Bycatch in fishing nets — especially gill nets and trammel nets can hold a seal underwater until it drowns. Seals have a weak breathing reflex, so drowning happens faster than in many other marine mammals.
- Plastic and waste — fishing lines, net fragments and plastic rings cause entanglement and wounds that don't grow out as adults.
- Human disturbance — walkers, kite surfers, drones and dogs on mud flats and sandbars force seals back into the water. During pup season this can be lethal.
- Disease — Phocine Distemper Virus (PDV) struck the Waddenzee in 1988 and 2002, killing thousands of common seals. Avian flu (H5N1) is a new concern since 2022.
- Food competition and climate change — shifting fish stocks influence what seals can sustainably eat.
The detail is at threats.
Is it working? — The numbers
Protection is measurable. The Netherlands counts seals annually in the Waddenzee and the Delta, often in collaboration with Wageningen Marine Research and the Trilateral Wadden Sea Secretariat. Key trends:
- Grey seal: from near-absent in 1980 to about 7,800 animals in the Dutch Waddenzee in 2024. A world-class recovery story.
- Common seal: strong growth up to around 2013, then stagnation and slight decline since 2022. Causes are being investigated; disturbance, food competition and virus outbreaks all play a role.
- Delta: both species are growing in the Oosterschelde and Westerschelde — a second natural core area is visibly emerging.
The current numbers and graphs are at counts.
What can you do?
Protection isn't only policy. Four practical things:
- Keep at least 100 metres from wild seals, and 30 metres from a stranded one until a warden arrives.
- Keep dogs leashed on beaches and salt marshes — even where it's allowed, it can be harmful.
- Report an animal in apparent distress to a seal warden rather than acting yourself.
- Support research and rehabilitation that works within the agreement — not centres whose goal is to admit as many seals as possible.