An example of a biohut under the water, Source: Ecocean

Copenhagen’s port: world record holder for fish kindergartens

Copenhagen’s port: world record holder for fish kindergartens

These devices, also known as biohuts, protect the vulnerable fish offspring to grow up in safety

WWF has declared that the Port of Copenhagen is the one containing the most fish kindergartens in the world – a total of 100 of these. And it took exactly one year, on this day, to reach that number after the first one was installed in 2021 by the environmental organization.

If you’re already wondering what fish kindergartens are, here’s the short answer. These are seashell filled cages that serve as nurseries for the baby fishes, where they can live safe from the reach of predators. If you want to know more details about this cool invention read below.

Protecting biodiversity under the sea level

The official name for the fishing nurseries is actually ‘biohuts’ and here are some facts about them:

  • Biohuts are a patented solution from the French company Ecocean;
  • The fish nurseries consist of a steel cage, which contains a small lattice box filled with empty oyster shells, where algae and small organisms can grow. The outer steel lattice protects the very young and small fish of less than three centimetres from larger predators, while the inner lattice with the oyster shells gives the fish both shelter and food;
  • Biohuts contribute to increased biodiversity in the form of more fish in a port. Increased fish stock can even migrate into the surrounding sea when they become large enough.

So, in essence, these biohuts act as oases for life and they help promote a richer life under water. In other words, they help the blue parts of Copenhagen become ‘greener’.

The Port of Copenhagen has one of the cleanest port environments in the world, but this hasn’t always been the case. With the fish kindergartens, we contribute to a wilder harbour nature, more fish and better biodiversity in the port, and at the same time, we have the opportunity to increase Copenhageners' awareness of life underwater. That is why we are also incredibly proud that today we are helping to secure the capital's world record in fish kindergartens,” declared on the occasion Bo Øksnebjerg, Secretary General of the WWF World Wide Fund for Nature.



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