📋 Tender Overview
Brown crabs cant resist the electromagnetic pull of underwater power cables and its changing their behaviour marine scientists say. The team behind a new study says the power cables linked to offshore renewable energy devices affect how crabs interact with the environment. The change affects their biology at a cellular level. Brown crabs are the UKs second most valuable crustacean catch and the most valuable inshore catch. So changes in their behaviour could have real economic consequences. Dr Alastair Lyndon from Heriot-Watt University said Underwater cables emit an electromagnetic field. When its at a strength of 500 microTeslas and above which is about five percent of the strength of a fridge door magnet the crabs seem to be attracted to it and just sit still. Thats not a problem in itself. But if theyre not moving theyre not foraging for food or seeking a mate. The change in activity levels also leads to changes in sugar metabolism - they store more sugar and produce less lactate just like humans. The scientists observed around 60 crabs at the St Abbs Marine Station in the Scottish Borders. They used the marine stations purpose-built aquarium laboratory for the experiment. Dr Kevin Scott at St Abbs Marine Station said The aquarium lab is composed entirely of non-metallic materials which means there is minimal electromagnetic interference. 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.A number of offshore wind farms are installed and planned around Scotlands coast and they will come with miles of associated underwater cables. The research team says not paying attention to or addressing the change in crabs behaviour could have long-term consequences. Dr Lyndon said Male brown crabs migrate up the east coast of Scotland. If miles of underwater cabling prove too difficult to resist theyll stay put. This could mean we have a build-up of male crabs in the south of Scotland and a paucity of them in the northeast and islands where they are incredibly important for fishermens livelihoods and local economies. One potential solution could be to bury the cables in the seafloor. However that can be expensive it makes maintenance more difficult and also its just not possible in some locations. We need to investigate further technical solutions so that we dont create negative environmental effects while trying to decarbonise our energy supply.
