Measurements of the Low Frequency Components of Active and Passive SoundsProduced by Dolphins

摘要

In the eastern tropical Pacific Ocean, yellowfin-Tuna, Thunnus Albacares,commonly associate with a variety of odontocete cetaceans including the spinner dolphin, Stenella longirostris, and the pan-tropical spotted dolphin, Stenella attenuata. Tuna fishermen frequently exploit this association by visually detecting the dolphins. The air-breathing dolphins remain closer to the surface and can be seen from a greater distance than the tuna. The association between tuna and dolphins may be related to a common food source, but the relative acuity of tuna sensory abilities, which must facilitate tuna dolphin association, has not been critically examined. Because there is a strong tuna-dolphin association, Schaefer & Oliver (2000) suggested there must be some dominant sensory cue that allows the tuna and dolphins to maintain the contact. Given that it is likely that much of the prey capture by the dolphins occurs at night, and at considerable depth, it seems reasonable that the tuna sense the presence of the dolphins acoustically rather than visually.