Arizona Public Radio | Your Source for NPR News
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

You can ding-dong-ditch to save these fish

"See a fish, ring the bell," says a website that lets visitors worldwide help fish in the Netherlands make it past a canal lock to their spawning ground.

Invented by ecologist Mark van Heukelum, the "fish doorbell" gives livestream viewers the chance to spot a fish lurking around a boat lock in the city of Utrecht. Ring the bell, snap a photo. With as many as a thousand pics per fish, the lock monitor gets word to open the gates and let the schools move along and get busy.

"We live in a country which is partly below sea level. And we build a lot of dams and dykes and locks, which is great, because it keeps our feet dry. But at the same time, we create many, many obstacles for fish," van Heukelum tells Weekend Edition Saturday.

In a conversation with NPR's Scott Simon, van Heukelum says he first envisioned his creation — in Dutch, visdeurbel — about four years ago while living near the lock and watching fish congregate at the gates. When the lock operator said he could open the historic gates, but only if he knows fish are waiting, "that was the spark that created the idea of a livestream and a doorbell."

Online, an underwater camera lets viewers catch murky closeups of fish approaching, and sometimes bumping up against, the Weerdsluis lock on the west side of Utrecht. Although it's rarely scheduled to open in the early spring when fish are migrating, clicking on the digital doorbell snaps pics of species including pike, perch, catfish, tench, and even a lone koi (probably a fugitive from private waters). The lock monitor gets a signal and when enough fishcam images are collected, the centuries-old sluice gate can be opened, by hand, to let the fish pass.

"In the Netherlands, they want to travel upstream when spring arrives because they want to go to shallow waters with a lot of water plants," van Heukelum explains. The lock is a barrier that also exposes the fish to predators like birds. But courtesy of the fish doorbell, "within a day or half a day, they can continue their journey."

The global fish fandom and the resulting lock openings also helps protect the ecosystem of the Dutch waterways. Van Heukelum says the fish doorbell eases a "big problem" by encouraging fish populations to thrive and enrich a hidden world of aquatic life.

The operation has captured millions of views over the past four years, and about 35,000 snapshots in just the last four weeks.

"There's so much help around the world and we're just so honored and proud that people are willing to help out."

Hiba Ahmad produced the audio version.

Copyright 2024 NPR. To see more, visit

Scott Simon is one of America's most admired writers and broadcasters. He is the host of Weekend Edition Saturday and is one of the hosts of NPR's morning news podcast Up First. He has reported from all fifty states, five continents, and ten wars, from El Salvador to Sarajevo to Afghanistan and Iraq. His books have chronicled character and characters, in war and peace, sports and art, tragedy and comedy.