Dutch City Uses “Fish Doorbell” to Aid Spring Migration

The city of Utrecht in the Netherlands has implemented a unique initiative to assist fish migrating to shallow spawning grounds this spring: a “fish doorbell,” The Associated Press reports.

This innovative system uses an underwater camera to livestream footage from the Weerdsluis lock to a website, allowing viewers to alert authorities when fish are being held up.

The concept is straightforward. When online viewers spot fish congregating at the lock, they can click a button that sends a screenshot to organizers. Once a sufficient number of fish are observed, a water worker is notified to open the lock, allowing the fish to continue their journey.

Now in its fifth year, the fish doorbell has garnered a global audience, attracting millions of viewers with its blend of slow TV and ecological activism.

While the livestream often displays a murky green scene with occasional bubbles, viewers are sometimes rewarded with the sight of fish swimming by. As water temperatures rise, the frequency of fish sightings increases.

The system aims to protect native freshwater species such as bream, pike, and bass. Without assistance, these fish can become trapped behind the lock during the spring migration, becoming vulnerable targets for predators due to the lock’s infrequent opening for boats during this period.

The “fish doorbell” is the brainchild of ecologist and concept developer Mark van Heukelum, who has expressed surprise and delight at the project’s widespread popularity and success.