In the recent Dutch elections, ultraconservative politician Geert Wilders came out on top. His slogan: “Zet Nederlanders weer op 1!” (Prioritise the Dutch again!) seems to have found resonance with many citizens throughout the country.  Many fishermen of the North Sea are not convinced, though. In order to reserve more food resources and water for Dutch fish, Wilders plans to expel fish not born within Dutch borders; fishermen fear that this might lead to a lower supply of fish in the already overexploited North Sea. Numerous fish from within the North Sea as well as outside of it will have to return to their hatching place: countless British fish are expected to forcibly return across the English Channel. “Those foreign fish are often predatory in nature and eat our Dutch fish, which hurts the Dutch and their economy. Since the flood of foreign fish has come to the Netherlands, we have seen a concerning increase in predatory behaviour and a spread of foreign diseases,” Wilders explained. Indeed, Atlantic Salmon is a major predator in the North Sea. Salmon hatch in rivers; and while they exactly remember which one, they often refuse to communicate this with humans.

Other politicians have already commented on Wilder’s proposal. Timmermans emphasised that he supports Dutch fishermen and foreign fish, stating: “There is plenty of water in the sea. All those foreign fish are currently doing the dirty work of slaughtering that our Dutch fish don’t want to do. We need them, both for the fishing industry and for the wellbeing of the Dutch fish”,  warning about the negative economic impact of such a plan. Ouwehand from the Animal Party said: “Elk leven maakt uit! We moeten die vissen redden op zee! (Every life matters! We must rescue fish at sea!) and “Als Wilders ze wegspoelt, keren wij het tij!” (If Wilders flushes them out, we turn the tide!).

Other big foreign predators of the Dutch North Sea include mammals such as whales. They often give birth outside of national borders as far north as Greenland. Being mammals, their skeleton looks more human than is the case for fish and they generally possess higher intelligence. Because of their human-like morphology, “they will be tolerated in the Netherlands since their looks are evidence that they can more easily adopt Dutch values” (Wilders).

When Wilders was asked to explain how to separate the fish by their birth-given nationality, he stated: “We’re gonna build a great wall through the North Sea and another one across the Frisian islands!”. The “great wall” refers to the Northern European Dam Enclosure (NEED), which aims at constructing a series of dams connecting France, Britain and Norway (Fig 1),2 as proposed by several oceanographers and other organisations such as the American Meteorological Society. The NEED was originally designed to protect northern Europe from rising sea levels, but since Wilders’ discovery that rising sea levels are a hoax, the dam will be used to stop incoming migration from outside the North Sea. Additionally, Wilders wants to realise a plan proposed by Van Diggelen in 18494, which aims to construct a dam between the Frisian islands as a second barrier to protect the Dutch fish stock from Belgian, German and other fish from the North Sea.

(Fig. 1: A Map The North European Enclosure Dam)

Banning foreign animals is not unique to the Netherlands: since 982 AD, Iceland has banned the import of foreign horses to the island. The ban was codified in 1882 and has remained ever since. It also abolishes the import of Icelandic horses who have been abroad, in the fear that they might have adopted a foreign disease, as well as any used horse equipment. Even the use of non-Icelandic horse names is not allowed if owners want to sell their horses. The ban has protected Icelandic horses for centuries; the Netherlands, being so dependent on its water resources, now aims to replicate the idea for its fish stock for similar reasons.

Although the concept of restricting the movement of animals along national borders has been around for centuries, Wilders’ proposal has caused a renewed debate about such laws among policy makers around the world. Nasser Bourita, the minister of foreign affairs of Morocco was the first to respond: “Seeing Wilders’ attitude towards Moroccan citizens, we will now ban any Dutch migratory birds from Morocco.” Migratory birds, such as spoonbills (Fig. 2), often migrate to warmer countries in the winter (just like Dutch humans). Once in Morocco, they put strain on local resources, taking them away from local birds.

The control of animal migration continues to be a hot topic in international politics. It remains to be seen if the streams of fish and other animals residing within Dutch borders will be stoppable and what impact the ban will have on the Netherlands. The SIBylle will keep you updated on this topic.

Fig. 2: Dutch Spoonbills using up precious Moroccan water in the Moroccan desert.


1. Wikipedia contributors, “Atlantic salmon,” Wikipedia, The Free Encyclopedia, (accessed December 17, 2023).

2. Wikipedia contributors, “Northern European Enclosure Dam,” Wikipedia, The Free Encyclopedia, (accessed December 17, 2023).

3. Groeskamp, Sjoerd, and Joakim Kjellsson. “NEED: The Northern European Enclosure Dam for if Climate Change Mitigation Fails”, Bulletin of the American Meteorological Society 101, 7 (2020): E1174-E1189, doi:

4.“Plan-van Diggelen.” Flevoland Erfgoed – Cultureel erfgoed, kunst en monumenten in Flevoland. Accessed December 17, 2023.

By Finn Gleichmann

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