Yes, you read that correctly. Utrecht has developed and installed the world’s first-ever doorbell for fish! Located at the Weerdsluis, the doorbell uses an underwater camera and a live stream to allow the lock keeper to open the lock when necessary to allow fish to pass through.

The doorbell allows fish to pass through Utrecht's Weerdsluis

Using the site visdeurbel.nl, members of the public can watch the live stream to see if there are any fish waiting at the lock. If there are, they simply press the doorbell button to alert the lock keeper, who will then open the lock. 

The system was established by Utrecht city ecologist Anne Nijs and underwater nature expert Mark van Heukelum, who say that Utrecht’s Oudegracht is like a highway for fish as they travel downstream in the winter and upstream in the summer to reach shallow water to lay their eggs. When they reach the lock, the fish will stop and wait for the lock to open so they can continue their journey.