Whilst scientists have known that marine species can detect electromagnetic fields for many decades research in the laboratory demonstrates this ability but has been difficult to transfer to field conditions. Do these cables affect behaviour and populations in the environment? This study has used field observations around existing cables to test the behavioural and ecological impact.
By MarEx 2016-10-24 17:55:45 The electromagnetic fields emanating from submerged power cables don’t have a significant impact on fish and invertebrates, according to a new report from the U.S. Bureau of Ocean Energy Management (BOEM). The purpose of the study was to determine the potential effects of energized, seabed deployed, power cables that are used for offshore renewable energy projects.
Offshore renewable energy is likely to be a major source of power for the U.S. Wind and wave technologies harness energy from an array of devices and then send the electricity to shore via cables. These cables will transmit either alternating current or direct current, and, if the cable uses alternating current, it will generate both electric and magnetic fields. Earlier research has shown that some fish and invertebrates are sensitive to electromagnetic fields which can alter their behaviour. However, worldwide, very few studies have been conducted to document these effects in the context of offshore energy installations.
The study was conducted on the submarine transmission cables that power the Southern Californian offshore oil platforms Heritage, Harmony, and Hondo. The experimental design tested for the effect of inshore versus deep water cable placement to depths of about 326 meters (1,069 feet).
The researchers found that few biological effects could be detected from patterns of species and their relative abundance, and there was no evidence of behavioural response by electro-sensitive species. BOEM’s Pacific Region office and research partners from the University of California Santa Barbara undertook the work. During the three-year study, researchers observed 4,671 individual fish and 30,523 invertebrates.
They concluded that given the lack of perceivable impact and the rapidity with which the electromagnetic fields produced by energized cables diminish, cable burial would not appear strictly necessary. Cable burial to one to two meters depth below the seafloor would be an adequate mitigation tool to decrease any potential exposure to electromagnetic fields.
The report is available here.