The effect of apparent predation risk on the respiratory behavior of the Florida gar (Lepisosteus platyrhincus)

The interbreath interval for aerial and aquatic ventilation was determined for seven Florida gars (Lepisosteus platyrhincus, Pisces, Lepisosteidae) before, during, and after exposure to the simulated threat of predation by a mounted great blue heron (Ardea herodius, Aves, Ardeidae). During exposure to the heron, air-breath interval increased by 118% while water-breath interval decreased by 13% as compared with the pre-heron period. This provides evidence that ecological factors not directly involved in the physiology of gas exchange can influence respiratory partitioning in fishes. It also supports the hypothesis that retention of water-breathing capacity in air-breathing fish can reduce the risk of aerial predation in these species.