Abstract: A method and apparatus for influencing living organisms by artificially induced magnetic fields. Of particular interest is the commercial harvesting of fish wherein the apparatus of the invention is used to controllably influence defined volumes of water in a manner to control the fish disposed therewithin by drastically upsetting or altering the orientation or "compass sense" of the fish. Of special interest is the commercial application of the method and apparatus to separate tuna and dolphins prior to setting the net around those dolphin schools beneath which tuna schools migrate in association. In this manner, the incidental mortality of dolphins will be reduced to zero.