08-17-2017, 12:00 AM
In another study, Bull and her colleagues monitored the marine life around three parts of the seafloor over three years. One area had a powered cable, another, an unpowered cable, and the third area had no cables at all. Both cabled areas attracted similar kinds and numbers of anemones and other sea life. In fact, more than twice as many fish and four times as many invertebrates hung around the cables than in the area with unaltered seafloor.
Measuring the magnetic field generated by the powered cable, Bull and colleagues found that the field quickly weakened with distance. By a meter away, the magnetic field was too meager to distinguish from background noise, Bull said. Even where the magnetic field was strongest, right on top of the cable, sea creatures didn t seem bothered.
In the third study, also presented February 26, Megan Wyman, an animal behaviorist at the University of California, Davis, and colleagues looked at an 85-kilometer-long, high-voltage power cable that bisects the San Francisco Bay. The team used acoustic sensors to monitor whether the activation of this cable in 2010 affected salmon migration. They found that the cable did not hinder young Chinook salmon (Oncorhynchus tshawytscha) from migrating through the bay from inland rivers.
It s great to hear that they don t seem to see any impact, said Genevra Harker-Klimes, a marine scientist at the Pacific Northwest National Laboratory in Sequim, Wash. There are a few loose ends that need to be tied up, but overall this is very positive news for offshore energy production.
