Wadden Sea seals

Located on the south-eastern margin of the North Sea and extending from Denmark in the north-east, along the German North Sea coast to the Dutch island of Texel in the south-west, the Wadden Sea is the world's largest unbroken system of intertidal sand and mud flats, where natural processes have been allowed to take their course undisturbed by human intervention throughout most of the area.

It is also a biodiversity hotspot. Every year, up to 12 million birds stop off here during their migration between their breeding grounds in the Arctic and their wintering areas in Africa. The region is home to over 10,000 species of plants and animals – including some 40,000 harbour seals and over 4,000 grey seals.

The return of the seals

So what's so special about seals in the Wadden Sea? Given the status of the populations only a few years ago, the numbers counted are nothing short of spectacular. Devastating outbreaks of phocine distemper, a potentially fatal virus, in 1988 and 2002, each wiped out between fifty and sixty percent of the region's harbour seal population. Grey seals, originally endemic to the Wadden Sea, had all but disappeared by the last quarter of the 20th century. Now they are back. And never since 1981, when organized counts of harbour seals across the Wadden Sea began, have researchers recorded a higher number of individuals.

World Heritage recognition

This success is due in no small measure to the efforts undertaken within the framework of the Wadden Sea Seals Agreement (WSSA). It was concluded under the auspices of the United Nations Convention on the Conservation of Migratory Species of Wild Animals (CMS) in 1990, and is administered by the Common Wadden Sea Secretariat (CWSS). The WSSA aims to promote close cooperation between the three parties: Denmark, Germany and the Netherlands, in order to achieve and maintain a favourable conservation status for the harbour seal population in the region. And it is achieving its aim, as key players beyond the Wadden Sea region acknowledge. The successful protection of harbour and gray seals over the last decades was one of the factors that contributed to the acceptance of the Dutch and German Wadden Sea as a UNESCO World Heritage Site in June 2009. The Danish part of the area followed suit in 2014. So this month, the three countries involved, and CMS and CWSS, can look back on a quarter century of fruitful cooperation, as the Agreement celebrates its 25th anniversary.

The centrepiece of the international cooperation is the continually updated Seal Management Plan. It deals with issues like habitat protection, research and monitoring, pollution and public information. The current plan not only covers the Wadden Sea stock of harbour seals, but also the breeding stocks of the grey seal, which is not covered by the WSSA. The plan seeks to strike a balance between conservation and management of the area.

At the eleventh hour, the WSSA was instrumental in keeping these iconic animal species from virtually disappearing from the region. By bringing all those involved together, including experts and managers, and by enhancing awareness of the conservation and protection needs of the seal populations in the Wadden Sea, the WSSA shows how various international organizations and bodies from within and outside of the UN system can successfully work together to bring an international legal instrument to life, to benefit the region it covers. Good news all round for the residents of the Wadden Sea.

Bradnee Chambers is Executive Secretary of the Bonn-based Convention on the Conservation of Migratory Species of Wild Animals.

Rüdiger Strempel is Head of the Common Wadden Sea Secretariat