World Heritage Site fish faces extinction

The North Sea houting (Coregonus oxyrinchus) is a whitefish that is endemic to the Wadden Sea, an area including the North Sea coasts of the Netherlands, Germany and Denmark. A critically small population in Denmark’s Vidaa River, estimated at 3,500 adult individuals in 2014, is the last remaining worldwide.

We call on the Danish authorities to prevent further decline of this fish through informed conservation planning and management before it is too late. The Wadden Sea is a World Heritage Site that harbours the world’s largest unbroken system of intertidal sand and mud flats. The North Sea houting is protected under the Bern Convention and the EU Habitats Directive.

Yet Denmark’s conservation efforts since 1992 have been limited to population estimates, insufficient regulation of the predatory great cormorant (Phalacrocorax carbo) and unsuccessful habitat‑restoration projects. The habitats needed by this fish for spawning and juvenile development are still unclear, so it is not possible to protect or restore them.

This basic knowledge is essential for future restoration projects. We urgently need to understand why the population is still in decline and to put effective conservation measures in place. The North Sea houting must not end up next to the great auk (Pinguinus impennis) on museum shelves.