Every year, thousands of spawning fish swim through the canals of Utrecht in the Netherlands. When they reach the Weerdsluis lock though, they often cannot travel further because the barrier — which acts as a dam — is rarely open. A new initiative, however, is now allowing regular citizens to help the fish get through, using an online “fish doorbell.”
You heard that right, officially known as a visdeurbel, the system consists of an internet-connected underwater camera located next to the lock gate. Using an app, members of the public can view the camera’s recording in real-time where and whenever they want.
If they notice that a significant number of fish are crowded outside the closed gate, users can notify the lock operator by ringing a digital doorbell on the app. At that point, the operator checks the camera for themselves and, if there’s indeed enough fish present to make it worthwhile, they will then manually open the gate and let the animals pass through.
As a result, the fish can start breeding sooner, and because they’re no longer stuck in one place, it’s less likely that they will be killed by birds such as grebes and cormorants. You can watch a video (in Dutch) of how the system works via this link.
Image source: Hoogheemraadschap De Stichtse Rijnlanden
