Jellyfish Shut Down France's Gravelines Nuclear Power Plant Again

It appears that animals may finally have had enough of human activity and technology.

Jellyfish disrupt the Gravelines nuclear power plant

Jellyfish have stopped a nuclear reactor in northern France for the second time, and this is far from nature's only recent strike against human infrastructure.

Whether these gloopy marine creatures were protesting French energy policy or had simply lost their way remains uncertain – they have issued no official statement.

Still, because it has occurred in two consecutive years on precisely the same date, the timing feels rather organised.

Four units at the Gravelines nuclear power plant were shut down on August 11, 2025 due to the "massive and unforeseeable presence of jellyfish" in the pumping stations for the water used to cool the reactors, EDF announced. (Sameer AL-DOUMY/AFP)

As Politico reports, Gravelines nuclear power plant spent hundreds of thousands of euros during 2025 attempting to prevent another incident, only for it to happen again 12 months later.

The plant was shut down as a precaution when an excessive number of jellyfish blocked the pumping systems it needs to operate.

Jokes aside, the episode is a serious consequence of climate change.

Rising water temperatures can result in greater numbers of plankton and animals eaten by jellyfish, while also speeding up their life cycles and lengthening their breeding seasons.

French utility provider EDF says fishing boats are now monitoring the surrounding waters around the clock to keep jellyfish blooms away from the nuclear power plant. It expects full-capacity operations to resume in the next few days.

Animals interfering with energy and science infrastructure

Pecking ravens were caught in the act at LIGO. (Robert Schofield)

Jellyfish are not the only animals with a record of interrupting human energy infrastructure.

In Connecticut last year, one raccoon was responsible for more than a thousand power outages, according to CT Insider.

Exactly what the raccoon did is unknown, but it somehow entered a substation and damaged equipment inside.

This unintentional sabotage left more than 2,500 local customers without electricity at one point, although repairs were completed quickly.

At times, these animal mishaps reach closer to the centre of science, as at Washington's Laser Interferometer Gravitational-Wave Observatory (LIGO).

The CERN site is currently undergoing major maintenance and upgrade work. (CERN)

There, logbooks from July 2017 show that ravens seeking a drink were pecking an ice-covered cooling pipe. The resulting vibrations affected the observatory's sensitive instruments, with the birds' pecks effectively producing glitches in the data.

Researchers at the site suspected ravens were behind particular anomalies in the observatory's readings and photographed the birds in the act. Moreover, when the observatory team artificially recreated pecks on the pipe, they generated the same data glitches seen previously.

The site was subsequently modified to prevent ice forming on the cooling pipes, Forbes reports – meaning the ravens had to find somewhere else to drink.

Then there is the puzzling case of the CERN baguette.

A 2009 bulletin from the CERN particle physics laboratory, home to the Large Hadron Collider, describes an event in which a power failure in the site's cryogenic systems required repairs over a couple of days.

Nobody truly knows what triggered the outage, but feathers and a piece of bread were discovered at the scene. The prevailing theory is that a small piece of baguette may have disrupted machinery somewhere along the way.

Human activity and animal behaviour

Although these accounts may be entertaining, they also highlight how human activity is intruding on the natural world around us.

Without intending to, we are passing our diseases to animals, altering their habitats, and changing their behaviour in many different ways.

Related: Animals Are Thriving in Chornobyl's Human-Free Zone, Study Finds

Against that background, a degree of pushback may be expected.

A 2022 study in Scientific Reports, conducted by researchers in the US and Indonesia, described how macaque monkeys in Bali have learned to steal belongings from people, then barter them for food before giving them back.

From jellyfish to monkeys, and from electricity substations to gravitational-wave detectors, the animal kingdom appears to be showing signs that it is not especially pleased with Homo sapiens.

This article was fact-checked by Rachel Garner and edited by Peter Dockrill. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.