Electro-orientation in the passive electric catfish,Ictalurus nebulosus LeS

Abstract

By means of conditioning experiments it was demonstrated in the laboratory that catfish show compass-orientation using more or less homogeneous, horizontally directed electric fields. Similar fields occur in their habitat. Evidence was found for the supposition that this kind of electro-orientation occurs spontaneously under natural circumstances. The lowest current density (horizontal d.c. field) in which the catfish showed orientation behaviour proved to be 8 × 10⁻¹²A/mm² in water with a specific resistivity of 25 Ohm·m.