Acoustic localization in an ostariophysian fish

Summary Under approximate free field conditions acoustic localization could be demonstrated in an ostariophysian fish, the ide (Leuciscus idus). The efficient vibration links of both sacculi with the unpaired swimbladder (via the Weberian ossicles) do apparently not preclude directional hearing in this important group of freshwater fish.The authors gratefully acknowledge the efforts of Mr M. Kleisma in the conduction of preliminary laboratory and field experiments. We thank Dr J. Ringelberg for making available to us the field facilities of the Limnological Laboratory, University of Amsterdam. Dr E. Meelis, Institute of Theoretical Biology, Leyden, has checked the applied statistics.