Interesting! I may have mentioned visiting a researcher at MBL, Woods Hole long ago. He rigged a shark tank and found that his shark subjects had an exquisitely sensitive electric field sense. The kind that might prove helpful in locating fish. I don't think he connected that result to an (unsuccessful) experiment that Faraday ran in the Thames, to measure the electric filed at either side of a bridge there due to the tidal current. A direct magnetic sense seems more plausible than mapping the electrical effect of ocean currents in the geomagnetic field, certainly.
On Thursday, May 6, 2021, 06:37:44 PM CDT, bernard cleyet <firstname.lastname@example.org> wrote: