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A lock keeper lets fish through in Utrecht
Photo: Anne Nijs
SPIEGEL:
Ms. Nijs, you are part of a team that runs a so-called fish doorbell in Utrecht. What's it all about?
Anne Nijs:
We installed an underwater camera at the Weerdsluis lock in Utrecht city center to see when fish gather in front of it and want to be let through, so to speak. And because we can't sit in front of the live stream the whole time, we have equipped the little house in which the lock keeper sits with an internet connection so that the camera's images can be streamed directly to our website. Now when users see a fish, they can press a button. We will then receive a message with a screenshot. If there are enough fish waiting in front of the lock, the lock keeper opens it.
SPIEGEL:
Why is that necessary?
Nijs:
Three years ago two of my colleagues were standing at the lock and saw fish swimming around in the water. The lock is around 200 years old and can only be opened and closed by hand. The lock was closed for months in winter and spring. There are no boats on the river during this time. The problem: When the water temperatures rise in spring, fish begin their migration - a few species even swim as far as Germany. However, they have to go through the lock to do this, so they had to wait. This can be very dangerous for fish; they lose energy and become easy prey, for example for cormorants or pike. This is why we started the project.
SPIEGEL:
That sounds like a human solidarity project, after it was people themselves who destroyed the fish's migration routes.
Nijs:
There is some truth in that. With the project we want to draw attention to this problem and show how many obstacles we have created for the animal world. And through the underwater camera, people see that there are not just old bicycles in the canals of Utrecht, but a diverse nature. The fish doorbell streamed a huge catfish onto the Internet, and yesterday a hunting cormorant. The underwater world is real, when people become more aware of it, they are more likely to want to protect it.
SPIEGEL:
How is the project being received?
Nijs:
At the beginning we distributed flyers in Utrecht and asked people if they wanted to take part. But it grew quickly.
SPIEGEL:
How big?
Nijs:
We get fan mail from all over the world - from the Philippines, from Australia. Last year we had more than a million unique users from around the world on our website. Almost half of them come from Germany. Funnily enough, the Dutch are only in fourth place in a country comparison. This year we started on March 1st and since then the traffic has been crazy. However, only around 1,000 people can use the doorbell at the same time. All other users can watch the stream on YouTube, but cannot ring the bell when they see fish.
SPIEGEL:
What is the fascination with the project?
Nijs:
I watch the live stream myself every day, sometimes in bed in the evening. This brings me down. My children love it too. I think people want to be the ones who see something special on stream. But they also love this sense of community, discussing and exchanging ideas together about discovered fish. It's a good cause, everyone can help.
SPIEGEL:
Fish migrate primarily at night. This is how they protect themselves from natural enemies such as birds. The stream also runs throughout the night. Are lock keepers waiting around the clock for information from the Internet?
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The Weerdsluis lock in Utrecht city center
Photo: Anne Nijs
Nijs:
No, it's not quite like that. The lock keeper is not on duty 24 hours a day. Sometimes he opens the lock again in the evening hours to let waiting fish through. And sometimes people ring the bell just for fun, even though there are no fish waiting in front of the lock.
SPIEGEL:
So there is a slightly harder door.
Nijs:
Sort of. But the project is not just about letting fish through and creating awareness among people. There is also a research level. Every time users press the doorbell, a screenshot is created and sent to us. This means we know which and how many fish swim through the river. We can compare the data with previous years and draw conclusions about stocks.
SPIEGEL:
What else do you discover besides catfish and hunting birds?
Nijs:
Once students jumped into the water and posed in front of the camera. Friends rang the bell and captured the moment.