FEEDING BEHAVIOR OF THE HUMPBACK WHALE, MEGAPTERA NOVAEANGLIAE, IN THE WESTERN NORTH ATLANTIC James H. W. Hain, 1 Gary R. Carter, 1 Scott D. Kraus, 2 Charles A. Mayo, 3 and Howard E. Winn 1 ABSTRACT Observations on the feeding behavior of the humpback whale, Megaptera novaeangliae, were made from aerial and surface platforms from 1977 to 1980 in the continental shelf waters of the north-eastern United States. The resulting catalog of behaviors includes two principal categories: Swim-ming/lunging behaviors and bubbling behaviors. A behavior from a given category may be used independently or in association with others, and by individual or groups of humpbacks. The first category includes surface lunging, circular swimming/thrashing, and the "inside loop" behavior. In the second category, a wide variety of feeding-associated bubbling behaviors are described, some for the first time. The structures formed by underwater exhalations are of two major types: 1) bubble cloud— a single, relatively large (4-7 m diameter), dome-shaped cloud formed of small, uniformly sized bubbles; and 2) bubble column— a smaller (1-1.5 m diameter) structure composed of larger, randomly sized bubbles, used in series or multiples. Both basic structures are employed in a variety of ways. Many of these behaviors are believed to be utilized to maintain naturally occurring concentrations of prey, which have been identified as the American sand lance, Ammodytes americanus, and occasionally as herring, Clupea harengus. This paper reports on the feeding behavior of the humpback whale, Megaptera novaeangliae, in the continental shelf waters of the northeastern United States. We describe several feeding be-haviors reported for the first time, as well as a number of behaviors known from other areas but not previously reported for these waters. Our col-lective observations provide the beginning of a more complete catalog than has previously been available. Early observations of humpback feeding be-havior were made by Ingebrigtsen (1929) from the Norwegian Sea near Bear Island: "It [the humpback] employed two methods of capturing 'krill' when the latter was on the sur-face of the water. One was to lie on its side on the surface and swim round in a circle at great speed, while it lashed the sea into a foam with flukes and tail and so formed a ring of foam. The frightened 'krill' gathered together in the circle. This done the humpback dived under the foam-ring and a moment later came up in the center to fill its open mouth with 'krill' and ■Graduate School of Oceanography, University of Rhode Island, Kingston, RI 02881. 2 Present address: New England Aquarium, Central Wharf Boston, MA 02110. 3 Provincetown Center for Coastal Studies, P.O. Box 826, Provincetown, MA 02657. ^n . « water, after which it lay on its side, closed its mouth, and the catch was completed. "The other method was to go a short distance below the surface of the water, swimming in a ring while at the same time it blew off. The air rose to the surface like a thick wall of air bub-bles and these formed the 'net'. The 'krill' saw this well of air bubbles, were frightened into the centre, and then the manoeuvre of the first method was repeated." Some 45 yr later, "bubblenetting" was reported from Alaskan humpbacks by Jurasz and Jurasz (1978), and later described in detail (Jurasz and Jurasz 1979). With the exception of the work of Watkins and Schevill (1979), accounts of feeding behavior of this species in the waters of the west-ern North Atlantic are few and largely anecdot-al. MATERIALS AND METHODS Observations were made from dedicated air-craft (a Cessna 337 Skymaster and a Beechcraft AT-11 4 ), from dedicated surface vessels (the 27.5 m Dolphin III and the 21.3 m Tioga), from plat-forms-of-opportunity, and from shore stations. Manuscript accepted November 1981. FISHERY BULLETIN: VOL. 80, NO. 2, 1982. "Reference to trade names does not imply endorsement by the National Marine Fisheries Service, NOAA. 259
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