Seal rehab: how it works, and when it's needed.

What is rehab?

Seal rehab is the temporary care of seals that would not survive in the wild — usually because of illness, injury, undernourishment, or, in rare cases, the loss of a mother before the pup can hunt on its own. The goal of rehab is always the same: return the animal to the sea as quickly and as healthy as possible. Rehab is therefore not a permanent zoo enclosure, not a tourist attraction, and not a refuge based on the idea that "they live better indoors than outdoors".

A stay consists of four phases: medical treatment (antibiotics, wound care, deworming, hydration), feeding (first tube feeding, then chunks of fish, eventually live fish), learning to hunt and swim in progressively larger pools, and the release on a quiet beach location. Only when the animal catches fish independently, has sufficient weight, and carries no infectious disease, does it return to the sea.

The Dutch rehab centres

The Netherlands has three major, recognised seal rehab centres and a few smaller partners. All have worked since 2020 under the common protocol of the Seal Agreement.

Zeehondencentrum Pieterburen is the oldest and best-known centre, founded in 1971 by Lenie 't Hart. It lies in a village on the Wadden coast and has an extensive research lab and educational public section alongside rehab. Ecomare on Texel combines rehab with a nature museum about the Wadden region. A Seal in Stellendam, founded in 2008, is the central rehab centre for the Delta. RTZ Termunten is smaller, focused on the Eems-Dollard region.

The quarantine protocol

Every newly admitted seal first enters quarantine: separated from other animals, in an individual pool, with dedicated carers and dedicated instruments. The reason is hard: seals can carry Phocine Distemper Virus (PDV), influenza, avian flu and various bacteria, some of which are infectious to other seals — and some to humans.

Quarantine lasts at least two weeks, with blood tests, nasal swabs and behavioural observation. Only when the animal is shown to be free of infectious disease does it move to a shared pool. This protocol is the global standard and is updated regularly — for example after the avian flu outbreaks from 2022, when the Pieterburen centre temporarily introduced extra protective clothing for carers.

When is rehab needed?

Under the Seal Agreement, four main criteria apply for admission. A seal warden decides using a standardised checklist:

• Disease with clear symptoms — for example active PDV infection (coughing, nasal mucus, fever), avian flu, severe pneumonia or infected wounds.
• Severe underweight — visibly protruding ribs and vertebrae, sunken flanks, weight below an age-specific threshold.
• Serious injury — open wounds, ingrown net fragments, dog bite wounds, propeller wounds.
• Confirmed orphan — a white pup without mother for at least 24 hours at a busy or unsafe location, verified by multiple observations.

What no longer falls under the criteria: a weaned pup resting, a "calling" pup whose mother may still return, or a healthy animal that merely seems "alone". Read more about the assessment at seal pup found.

The Seal Agreement debate

The 2020 agreement was not uncontested. Before its introduction, Dutch centres together admitted 500–800 seals per year; since 2020 that figure sits at a few hundred. Some staff and former directors, especially within Pieterburen under Lenie 't Hart, felt the threshold for intervention had been set too high: "an animal that can be helped, must be helped". Others — scientists from Wageningen Marine Research and universities, most fellow centres, and most rangers — argued the earlier practice went too far in well-meant interference.

Scientifically the balance is now clear: unnecessary rehab harms. The stress of capture and transport, disruption of the natural learning process (hunting, navigating, social bonds) and the risks of pool life are real costs. Current population numbers confirm that nature largely manages on its own: see counts. The debate over exceptional cases remains alive — and healthy.

How long in rehab?

The average stay is 6 to 12 weeks, but it varies considerably per animal. An undernourished pup that gains weight quickly can return in 5–6 weeks; an animal with a deep wound or a PDV infection may need 3–4 months. During the stay the animal is touched as little as possible: the more wild behaviour it retains, the greater the chance of a successful return.

An individual file is kept per animal: admission weight, feeding schedule, medical interventions, behavioural observations, hunting skill, and results of infection tests. At the final medical check before release, the animal is marked with a yellow or orange "headstart" identification clip, so researchers and rangers can recognise it later in the wild.

Release

Release takes place on quiet beaches, far from walking routes and dogs. Frequently used locations are the North Sea coast of Texel, the beach near Pieterburen, the north side of Schiermonnikoog and the Brouwersdam. In the past, releases were public events with hundreds of spectators; today they happen preferably quietly, to avoid stress and press attention. Some centres later publish photos and GPS tracks of the released animals.

A successfully released seal swims away within a few hours, often heading for known feeding grounds such as the Dogger Bank or the Vlakte van de Raan. Tracking research shows that most released animals reintegrate into wild groups within weeks.

How to support

The recognised rehab centres run largely on donations, memberships, funds and — for some — visitor income. Anyone who wants to contribute: become a donor or "adopt" an animal via Pieterburen, Ecomare or A Seal. More important than financial support is behavioural support: keep your distance, keep your dog on the leash, report via a warden instead of intervening yourself, and respect closed nursery areas. That keeps the Dutch seal population healthy — with as few animals as possible needing rehab.