'Megaclicks': Acoustic Click Trains and Buzzes Produced During Night-time Foraging of Humpback Whales (Megaptera Novaeangliae)

• Main Authors: Stimpert, Alison, Wiley, David N, Au, Whitlow W.L., Johnson, Mark P, Arsenault, Roland J.
• Format: Text
• Language: unknown
• Published: University of New Hampshire Scholars' Repository 2007
• Subjects: Whale Tracking; acoustic behaviour; northwest Atlantic; baleen whale; click; DTAG; feeding; Marine Biology; baleen whales; Megaptera novaeangliae; Northwest Atlantic
• Online Access: https://scholars.unh.edu/ccom/1039; http://rsbl.royalsocietypublishing.org/content/3/5/467

Humpback whales (Megaptera novaeangliae) exhibit a variety of foraging behaviours, but neither they nor any baleen whale are known to produce broadband clicks in association with feeding, as do many odontocetes. We recorded underwater behaviour of humpback whales in a northwest Atlantic feeding area using suction-cup attached, multi-sensor, acoustic tags (DTAGs). Here we describe the first recordings of click production associated with underwater lunges from baleen whales. Recordings of over 34 000 ‘megapclicks’ from two whales indicated relatively low received levels at the tag (between 143 and 154 dB re 1 mPa pp), most energy below 2 kHz, and interclick intervals often decreasing towards the end of click trains to form a buzz. All clicks were recorded during night-time hours. Sharp body rolls also occurred at the end of click bouts containing buzzes, suggesting feeding events. This acoustic behaviour seems to form part of a night-time feeding tactic for humpbacks and also expands the known acoustic repertoire of baleen whales in general.