‘Mesmerized’ by Undersea Power Cables, Brown Crabs Stay Frozen in Electromagnetic Field


Oct 11, 2021


Image Credits: PNGegg

Underwater power cables have a strange, mesmerizing effect on brown crabs. The electromagnetic field emitted by the cables attracts the crabs, making them freeze in their place — as if someone from the Harry Potter-universe cast the “Stupefy!” spell on them.

Unfortunately, unlike the effect of the Potter-spell, this one isn’t temporary. This attraction, and the subsequent act of freezing on the part of the crabs, spells doom for the survival of the species.

Published in the Journal of Marine Science and Engineering, a new study found that rising levels of electromagnetism led to cellular changes in the crabs’ blood cells.

“We found that exposure to higher levels of electromagnetic field strength changed the number of blood cells in the crabs’ bodies. This could have a range of consequences, like making them more susceptible to bacterial infection,” co-author of the study, Kevin Scott from the St. Abbs Marine Station in the U.K., where this experiment was conducted, said in a statement.

Moreover, “the change in activity levels [as a result of staying put in one place] also leads to changes in sugar metabolism — they store more sugar and produce less lactate, just like humans,” says Alastair Lyndon, an associate professor at the center for marine biology and diversity at Heriot-Watt University in the U.K., who co-authored the study.

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Unfortunately, biological changes in crabs are not the scientists’ only concern. “[I]f they’re not moving, they’re not foraging for food or seeking a mate,” Lyndon explained. While the lack of foraging could endanger the lives of the existing brown crabs, the lack of reproduction could threaten species’ survival too.

Known scientifically as Cancer Pagurus, brown crabs are most commonly found in the North Atlantic Ocean. They’re also called the “edible crab” and are, reportedly, the U.K.’s second most valuable crustacean catch, and most valuable inshore catch. More than 60,000 tonnes of brown crabs are caught annually.

Because it’s a commonly eaten species of crustaceans, the researchers are worried the impact of electromagnetism on the species could also threaten people’s livelihoods and contribute to food insecurity.

“Male brown crabs migrate up the east coast of Scotland. If miles of underwater cabling prove too difficult to resist, they’ll stay put. This could mean we have a buildup of male crabs in the south of Scotland and a paucity of them in the northeast and islands, where they are incredibly important for fishermen’s livelihoods and local economies,” Lyndon said.

What is the solution, then? Well, researchers are trying to explore the best of action here but haven’t zeroed in one yet. Lyndon said burying the cables under the floor of the sea is an option, but it could prove to be an expensive venture and be challenging to implement in several places.

So, until the scientists can devise a solution, I’m hoping “Rennervate!” could be a valuable counter-spell to un-“Stupefy!” these crustaceans.


Written By Devrupa Rakshit

Devrupa Rakshit is an Associate Editor at The Swaddle. She is a lawyer by education, a poet by accident, a painter by shaukh, and autistic by birth. You can find her on Instagram @devruparakshit.


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