visdeurbel.nl
The Fish Doorbell is a system located at Utrecht’s Weerdsluis lock that supports migrating fish during their spring journey to spawning grounds. An underwater camera provides a livestream of the lock; viewers who spot fish can ring a digital doorbell to notify the lock keeper, who opens the lock when enough fish are waiting. The 2026 season has concluded, and the system will resume operation on March 1, 2027.