You Can Help Migrating Fish Traverse a Dutch Canal By Ringing This Digital ‘Doorbell’

The live stream from the Netherlands, which lets viewers notify a boat lock operator when fish need to be let through, has become a popular pastime for people around the world

a fish appears on the live stream underwater
A fish appears on the live stream from the Netherlands' Weerdsluis lock in Utrecht.

In 2020, ecologist Mark van Heukelum was strolling through Utrecht in the Netherlands, when he noticed that fish had congregated in a canal on one side of a 200-year-old boat lock, writes the New York Times’ Callie Holtermann. Since boats do not usually travel through the city’s canals in the spring, the lock hadn’t been opened, and the creatures were trapped behind it.

“In the early spring, when the water gets warmer, some fish species migrate to shallower water, and they swim right through the center of Utrecht looking for a place to spawn and reproduce,” ecologist Anne Nijs tells BBC Wildlife’s Melissa Hobson.

But the lock cuts off the animals’ progress—and waiting near it puts fish in a life-threatening position. When fish are stuck in the canal, predators like grebes and cormorants can more easily snatch them.

To help fish migrate safely during the canal’s quiet season, Nijs and van Heukelum came up with an innovative solution: the fish doorbell (or de Visdeurbel in Dutch). Launched in spring 2021, the webpage features a live stream from an underwater camera, allowing viewers worldwide to check for fish waiting at the closed lock—then, they click a pink button on the site when the animals appear on screen.

Each time a user “rings” the doorbell, the service snaps a picture of the fish and sends it to a team of ecologists. After enough fish are waiting, they notify the lock’s operator that the gate should be opened.

Nijs and van Heukelum worked with Utrecht’s government and local water authorities to establish the doorbell strategy.

“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 NPR’s Weekend Edition Saturday.

Visdeurbel Utrecht Live Stream

Now in its fourth year of operation, the doorbell usually runs between March and late June. With predators more active during the daytime, the website recommends visiting the live stream at night to spot fish swimming in the safety of darkness.

When the doorbell first launched on March 29, 2021, many Utrecht residents thought it was an April Fools’ joke. But now, it has become widely popular. This year, the fish doorbell has had roughly 1.2 million unique users since March 1, and its viewers have rung the doorbell more than 40,000 times.

“Some people are obsessed by it, and we receive a lot of fan mail,” Nijs tells BBC Wildlife.

While tuning in from the website is ideal, as that is the only place viewers can click the doorbell, the stream is also available on YouTube. The website can only host about 950 streamers at once, so any additional viewers get directed to the YouTube video.

Wildlife live streams, from cheetah births to beluga whale migrations, are often popular online for their educational and entertainment value—and the fish doorbell is no different.

“Somebody who had been very depressed and anxious reached out to me and said that the fish doorbell was the only thing that … could make her feel calm and distract her from difficult thoughts,” Nijs tells Scientific American’s Riis Williams. “It really is so special for people to knowingly watch something with 900 other people around the world at the same time.”

Watching animals online can lead people to care more for wildlife, according to a 2018 study published in the Journal of Ecotourism. A pair of researchers investigated whether viewing live streams of brown bears at Alaska’s Katmai National Park and Preserve yielded positive environmental sentiment. They wrote that “the ability of online viewing to generate a positive emotional connection to bears was observed.”

With the doorbell in particular, people around the world can have a direct impact on the wildlife they see in the live stream—which is a large part of its success, Lisa Brideau, a climate policy specialist in Canada, tells the New York Times. But with the live stream’s legion of existing users, she suggests that people look for other ways to help wildlife closer to home.

“The doorbell is covered,” she tells the publication. “Where else can we put this energy?”

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