Since 1978, the Netherlands, Germany and Denmark have cooperated to protect the Wadden Sea as an ecological entity. The Guiding Principle of the Trilateral Wadden Sea Cooperation is to “achieve, as far as possible, a natural and sustainable ecosystem in which natural processes proceed in an undisturbed way”. The Common Wadden Sea Secretariat was established in 1987 and has since coordinated the work of the Cooperation.