Far beyond most undersea cables, and even then the article is concerned not with the largest long-distance high-voltage/high-current transmission lines, but wit

Far beyond most undersea cables, and even then the article is concerned not with the largest long-distance high-voltage/high-current transmission lines, but with individual wind turbines. Power loss scales with the square of current (P=I^2 x R), and copper is already expensive, so they typically use step-up transformers to reduce the current in a wind farm to something on the order of a hundred amps. I've pushed 40,000 amps for a distance of a couple hundred millimeters, using some giant water-cooled electrodes for a resistance welding application...but there's zero reason to have 14 kA as a distribution line in a wind farm, that's absurd. Yes, some lobster and crab larvae will probably also exhibit decreased carapace height if they're squished by the wire as it is fed out onto the sea floor...but that's about the same distance as the region in which they'll be affected by magnetic currents.