Bottom side-roll feeding by humpback whales (Megaptera novaeangliae) in the southern Gulf of Maine, U.S.A.

• Published in: Marine Mammal Science
• Main Authors: Ware, Colin, Wiley, David N., Friedlaender, Ari S., Weinrich, Mason, Hazen, Elliott L., Bocconcelli, Alessandro, Parks, Susan E., Stimpert, Alison K., Thompson, Mike A., Abernathy, Kyler
• Other Authors: Oceanography
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2013
• Subjects: humpback whale; Megaptera novaeangliae; bottom feeding; bottom side-rolls; coordination; entanglement; Humpback Whale
• Online Access: https://hdl.handle.net/10945/46127

The article of record as published may be located at http://dx.doi.org/10.1111/mms.12053 Humpback whales (Megaptera novaeangliae) are known for the variety and complexity of their feeding behaviors. Here we report on the use of synchronous motion and acoustic recording tags (DTAGs) to provide the first detailed kinematic descriptions of humpback whales using bottom side-rolls (BSRs) to feed along the seafloor. We recorded 3,505 events from 19 animals (individual range 8–722). By animal, mean BSR duration ranged from 14.1 s to 36.2 s.; mean body roll angle from 80º to 121º, and mean pitch from 7º to 38º. The median interval between sequential BSRs, by animal, ranged from 24.0 s to 63.6 s and animals tended to maintain a consistent BSR heading during long BSR series encompassing multiple dives. BSRs were most frequent between 2200 and 0400. We identify three classes of behavior: simple side-roll, side-roll inversion, and repetitive scooping. Results indicate that BSR feeding is a common technique in the study area and there is both coordination and noncoordination between animals. We argue that this behavior is not lunge feeding as normally characterized, because animals are moving slowly through the event. The behavior also leads to vulnerability to entanglement in bottom-set fishing gear, a major mortality factor for the species. Funding for TrackPlot development was provided by an ONR grant to Colin Ware (ONR N0014091601) and from NOAA Grant #NA05NOS4001153 to the Center for Coastal and Ocean Mapping. Field work and analysis was supported by Office of Naval Research grant N00014-08-0630 (to SEP, DW), National Oceanographic Partnership Program (to DW), the Stellwagen Bank National Marine Sanctuary and the Office of National Marine Sanctuaries.