Abstract
Whales found in the north Pacific are known to migrate over several thousand kilometers, from the Alaskan coast where they heartily feed during the summer to low latitude waters where they breed during the winter. Therefore, it is assumed that whales are using the "deep sound channel" for their long-distance communication. The main objective of this study is to clarify the behaviors of baleen whales from the standpoint of acoustical oceanography. Hence, authors investigated the possibility of long distance communication in various species of baleen whales, by simulating the long-distance propagation of their sound transmission, by applying the mode theory to actual sound speed profiles and by simulating their transmission frequencies. As a result, the possibility of long distance communication among blue whales using the deep sound channel was indicated. It was also indicated that communication among fin whales and blue whales can be made possible by coming close to shore slopes such as the Island of Hawaii.