Scientists have discovered that underwater power cables enchant brown crabs and cause biological changes that can increase the risk of infection.
Cables for offshore renewable energy emit an electromagnetic field that attracts the crabs and causes them to sit still.
Study of about 60 brown crabs at St. Abbes Marine Station Scottish Borders The high levels of electromagnetism caused cellular changes in the crabs, affecting the blood cells.
The crabs seem to be attracted to it and are just sitting still
Alastair Linden of Heriot-Watt University said: “Underwater strings emit an electromagnetic field.
“When it’s at a strength of 500 microtesla and above, which is about 5% of the strength of a fridge door magnet, the crabs are attracted to it and just settle down.
“That in itself is not a problem. But if they are not moving they are not looking for food or a mate.
“Changes in activity levels also alter sugar metabolism—they store more sugar and produce less lactate, like humans.”
The researchers used the Marine Station’s purpose-built aquarium laboratory for the experiment.
Kevin Scott of St Abbes Marine Station said: “The Aquarium Lab is made entirely of non-metallic materials, which means there is minimal electromagnetic interference.
“We found that exposure to high levels of electromagnetic field strength changed the number of blood cells in the crabs’ bodies.
“This can have many consequences, such as making them more vulnerable to bacterial infections.”
The team warns that changes in the species’ behavior could affect fishing markets, as the crab is the UK’s second most valuable crustacean catch and the most valuable inshore catch.
A number of offshore wind farms are installed and planned around the coast of Scotland, which require extensive underwater cabling, and the researchers said further work is needed to ensure that they support Scotland’s brown crab population. do not destabilize.
Mr Lyndon said: “Male brown crabs migrate to the east coast of Scotland. If the miles of underwater cable laying prove too difficult to resist, they will stay put.
“This could mean that we have a buildup of male crabs in the south of Scotland, and a lack of them in the north east and islands, where they are incredibly important to fishermen’s livelihoods and local economies.”
He said one solution would be to bury the cables in the ocean floor, but warned that this could be costly, meaning maintenance is more challenging and cannot be done in some places.
Mr Lyndon said: “We need to investigate more technical solutions so that we don’t create negative environmental impacts when trying to decarbonize our energy supply.”
The study was published in the Journal of Marine Science and Engineering.