Electroreception: Strategies for Separation of Signals from Noise

The electric sense is ancestral to fishes and is present in most non-teleosts as well as certain teleost species. The electrosensory world of fishes is rich with electric fields from a multitude of sources includ- ing the earth’s magnetic field and the bodies of all aquatic organisms including the electrosensing fish, itself. The fish’s exquisite sensitivity to these fields allows it to orient, navigate, communicate and even detect and localize other fish, both prey and conspecifics. Electroreceptors are of two basic morphologi- cal types, ampullary and tuberous. Ampullary receptors, the ancestral type, are sensitive to extremely weak, low-frequency electric signals. Tuberous receptors represent a specialization of the weakly electric teleost fishes and are most sensitive to higher frequencies near to the frequency of the fish’s own electric organ discharge (EOD).