Utrecht’s innovative fish doorbell transforms conservation efforts by allowing people worldwide to help fish complete their natural migration.
A unique solution to help fish migration has returned to the Dutch city of Utrecht for its fifth consecutive year. Fish doorbell season went live on March 3, allowing people worldwide to help fish navigate through a city lock.
The fish doorbell system uses a live underwater camera that shows fish waiting to swim upstream. Viewers can press a virtual button to alert the lock keeper at the Weerdsluis lock when fish appear, signalling them to open the gate.
Each spring, fish like bream, pike, and bass migrate from the River Vecht to the River Kromme to lay their eggs. The Weerdsluis lock is a critical passage in their journey.
During early spring, the lock remains mostly closed for boats. This can leave fish stranded for weeks, making them easy targets for predators along the route.
Two ecologists – Anne Nijs and Mark van Heukelum – created the fish doorbell in 2021 as a practical solution to this problem. Their innovation has since helped thousands of fish continue their natural migration patterns.
The process is simple. People watching the live stream can click a button whenever they spot fish. This sends an alert to the lock keeper, who can then open the door right away.
This quick response allows the fish to continue their journey to find suitable spawning grounds. Thanks to the fish doorbell system, thousands of fish successfully make the trip each year.
The fish doorbell operates during the peak migration season, which runs from early March to early May. During this period, viewers from around the world take turns monitoring the underwater camera feed.
Fish play a vital role in maintaining water balance by eating algae and small animals. Some species also serve as indicators of water quality, as they can only survive in clean, oxygen-rich environments.
The underwater camera connected to the fish doorbell offers additional benefits for research. Ecologists use videos and screenshots to monitor which fish species travel through the canal and when they arrive.
This data helps them track the size, gender, arrival times, and behavioural patterns of different fish species. They can also compare this information with observations from previous years to identify changes or trends in fish populations. These observations also help with monitoring the water quality in and around Utretct.
What started as a small local initiative has grown into an international sensation. Last year, the fish doorbell attracted 2.7 million viewers from countries including the United States, Brazil, and New Zealand.
Viewers rang the fish doorbell more than 40,000 times during the 2024 season, helping fish continue their journey through Utrecht’s waterways.
People share their excitement about the fish doorbell camera on social media platforms like X and TikTok when it goes live each spring. The ecologists behind the project have even received fan mail from enthusiastic viewers who regularly use the fish doorbell.
See also: How to Be a Citizen Scientist: A Beginner’s Guide
The fish doorbell demonstrates how simple technology and public participation can support wildlife conservation. By connecting people directly to wildlife migration, the project increases awareness about human impacts on natural systems.
Water authorities in Utrecht continue working on more permanent solutions. Until these passages are complete, the fish doorbell provides an effective temporary solution that engages the public in conservation efforts. Its interactive nature makes it particularly effective at raising awareness about fish migration challenges.
The success of Utrecht’s fish doorbell shows how digital technology can create new ways for people to participate in environmental protection. It transforms what would normally be an invisible wildlife challenge into an interactive experience anyone can join from anywhere in the world.
