A seafloor array of recorders spanning the Tasman Sea has measured the electric field signature of a major warm-core ring embedded in the East Australian Current. Theory for motional electromagnetic induction allows the electric measurements to be interpreted in terms of barotropic water velocity. Water transport and kinetic energy estimates thus obtained show a concentration of mesoscale activity near the Australian coast. The total circulation of the particular ring is estimated to be of the order of 100 Sv.