A comparison of the song of humpback whales (Megaptera novaeangliae) wintering in the Northwestern and Main Hawaiian Islands.

Abstract

An extensive study of the population structure of North Pacific humpback whales (SPLASH) has revealed that many of the whales feeding in the Aleutian Islands and the Bering Sea are not observed in known wintering and breeding areas in the Pacific. Recent findings suggest that the Northwestern Hawaiian Islands (NWHIs) represent a previously undocumented wintering area that may be distinct from the Main Hawaiian Islands’ (MHIs’) wintering ground. To examine this issue further, data from Ecological Acoustic Recorders (EARs) deployed at five locations in the NWHIs and MHIs were analyzed to compare the structure of songs produced by whales in both areas. Previous research suggests that songs from different breeding groups differ from one another, providing a method to evaluate whether whales in the NWHIs are part of the same breeding group as those in the MHIs. Recordings from each site were randomly selected, and song units were classified and counted to compare between sites. Preliminary results indicate that there are differences between the NWHIs and MHIs. These findings suggest that further work using photo ID should be undertaken to confirm whether whales in the NWHIs are indeed those feeding in the Aleutians and the Bering Sea.