Electric phenomena in the habitat of the catfishIctalurus nebulosus LeS

SummaryThe biotic and abiotic electric phenomena in the habitat of the electrosensitive catfish,Ictalurus nebulosus LeS were investigated. Fish, insect larvae, tadpoles and snails proved to possess electric fields that can be described as stationary fields of the dipole type, upon which fluctuations, due to respiration or other movements, are superimposed. The frequency components of these fields fall within the DC to 10 Hz range, whereas the potential gradients are in the order of magnitude of 10 mV/m. The maximal potential differences found were several millivolts. These measurements were carried out in tap water with a specific resistance ρ = 20 Ω · m. Further, hydroelectric fields were measured in some find-localities ofIctalurus. Potential gradients up to 15 mV/m have been recorded in water with a specific resistance ρ = 110 Ω · m. These fields proved to be stationary, fairly constant in direction and strength, and strongly dependent on the structure of the bottom of the pool and the depth of the water. The possible significance of these biotic and abiotic fields toIctalurus is discussed.