Use of social sounds by humpback whales (Megaptera novaeangliae) in the Western Antarctic Peninsula feeding grounds

Abstract

Humpback whales (Megaptera novaeangliae) are renowned for the complex structured songs produced by males. A second, relatively understudied area of humpback acoustic communication concerns un-patterned sounds known as “social sounds,” produced by both males and females. This paper explores the use of non-song sounds by humpback whales on the Western Antarctic Peninsula feeding ground. To obtain high quality, close range recordings of humpback whale social sounds, digital acoustic tags (DTAGs) were placed on humpback whales exhibiting foraging behavior during the austral autumn of 2009 and 2010. Overall vocalization rates of two types of social sounds, “wops” and “grunts,” showed that there was not a significant diurnal pattern in call production, suggesting that perhaps these calls are not used exclusively for foraging on the feeding ground. These results enhance our understanding of this acoustically advanced species, and will also be useful in conservation and management efforts. The acoustic parameters of the calls that were identified can be used in the development of automatic detection algorithms, and the behavioral contexts during call production can assist in interpretation of passive acoustic monitoring research on humpback whales, and potentially other baleen whale species as well.