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Feeding behavior of the humpback whale, Megaptera novaeangliae, in the western North Atlantic
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Observations on the feeding behavior of the humpback whale, Megapteranovaeangliae, were made from aerial and surface platforms fTom 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 (4-7m 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.
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... Humpback whales Megaptera novaeangliae serve as an excellent study species for foraging behavior and strategy due to their high degree of behavioral plasticity (Jurasz & Jurasz 1979). The suite of strategies documented in humpback whales include surface or subsurface lunging , the use of bubbles (Hain et al. 1982) or body parts to corral prey (McMillan et al. 2019), or scooping prey from the substrate (Ware et al. 2014). Multiple strategies are often employed within single populations, demonstrating the whales' ability to adapt and innovate in re sponse to surrounding environmental conditions such as prey behavior and abundance (Weinrich et al. 1992, Allen et al. 2013 or water temperature (Owen et al. 2019). ...
... Bubbles are also used in other feeding formations besides nets, such as clouds (i.e. production of a large, single mass of very small bubbles (Hain et al. 1982, Wiley et al. 2011 or curtains (i.e. a straight line of bubbles; Hain et al. 1982, Acevedo et al. 2011. ...
... Bubbles are also used in other feeding formations besides nets, such as clouds (i.e. production of a large, single mass of very small bubbles (Hain et al. 1982, Wiley et al. 2011 or curtains (i.e. a straight line of bubbles; Hain et al. 1982, Acevedo et al. 2011. ...
The innovation of new foraging strategies allows species to optimize their foraging in response to changing conditions. Humpback whales provide a good study species for this concept, as they utilize multiple novel foraging tactics across populations in diverse environments. Bubble-net feeding (BNF), commonly seen in the Northern Hemisphere, has emerged as a foraging innovation in the past 20 yr within the Western Antarctic Peninsula. Using sightings data from 2015-2023, we found that BNF was present in every study year, with an annual average of 30% of foraging sightings. This data was supplemented with 26 animal-born tags deployed over the same study period. Of these tags, 12 detected instances of BNF, with BNF making up an average of 19% of the foraging lunges detected. There were seasonal trends in BNF sightings, as it was observed significantly more often at the beginning of the feeding season (January) before declining. BNF group sizes (mean: 3.41) were significantly larger than non-BNF surface feeding groups (mean: 2.21). This observation is consistent with BNF in the Northern Hemisphere, which also appears to primarily be a group foraging strategy. The seasonal pattern and relatively recent emergence of BNF suggests that its use is likely tied to specific environmental conditions, which should be investigated by comparing BNF with variables such as prey density and light availability. The social transmission of novel foraging strategies across other populations further suggests that the prevalence of this strategy likely occurs through social learning.
... Humpback whales (Megaptera novaeangliae) are known to produce complex bubble structures-'bubble-nets' [22][23][24][25]. They do so by releasing air from their blowhole as they swim in a circular path below the surface. ...
... Aspects of bubble-nets and net-producing whales suggest that whales manufacture these nets as foraging tools [2]. For example, the use of bubble-nets has been observed repeatedly in association with foraging in allopatric humpback whale populations [23,24,[26][27][28][29]. Several researchers have noted differences in the size and shape of bubble-nets produced by whales between, and notably within, the same populations [24,25,30]. ...
Several animal species use tools for foraging; however, very few manufacture and/or modify those tools. Humpback whales, which manufacture bubble-net tools while foraging, are among these rare species. Using animal-borne tag and unoccupied aerial system technologies, we examine bubble-nets manufactured by solitary humpback whales (Megaptera novaeangliae) in Southeast Alaska while feeding on krill. We demonstrate that the nets consist of internally tangential rings and suggest that whales actively control the number of rings in a net, net size and depth and the horizontal spacing between neighbouring bubbles. We argue that whales regulate these net structural elements to increase per-lunge prey intake by, on average, sevenfold. We measured breath rate and swimming and lunge kinematics to show that the resulting increase in prey density does not increase energetic expenditure. Our results provide a novel insight into how bubble-net tools manufactured by solitary foraging humpback whales act to increase foraging efficiency.
... Caused by the ecological constrains of life in oceans, humpback whales have also developed some unique individual and social behavioural features, like breaching behaviour (Fig.1), generation of the most complex sound among the swimming animals in general and in their group foraging process [7,8] and utilization of a smart bubble net hunting technique [9], to name a few [2]. ...
... In the latter bubble net fishing method, humpback whales exhibit a very clever and corporative social behaviour by generation of bubble columns (with an approximate diameter of 4-7 m) and bubble clouds (1-1.5 m) to maintain naturally concentrations of prey, as clarified by Hain et al. [9]. ...
In this paper, hydrodynamic effects of ventral pleats covering mouth and bell parts of humpback whales are studied for the first time. In this regard, turbulent flows over a simplified model of the animal body as a half grooved ellipsoid are numerically simulated using Lam-Bremhorst low Reynolds turbulence model resolving to the wall at different angles of attack and sideslip. The results show that presence of the ventral pleats leads to formation of low speed strips and shear layer/vortex on the bottom surface of the animal, which in turn results in a relatively higher pressure region on the bell and higher drag coefficient compared to a case without grooves. In this way, pleats generate lift and contribute to buoyancy force and also increase tendency of flow separation. The results also depict superior performance of the grooved body at sideslip angles. Furthermore, results of cavitating flow simulation over the grooved model showed a suppression of lift generation contribution of the ventral grooved surface in cavitating conditions, the most similar situations to bubbly flows experienced by humpback whales in bubble net fishing environment.
... Baleen whales, including the humpback whale (Megaptera novaeangliae), exhibit distinct bubble-related behaviors (Moreno & Macgregor, 2019;Reidenberg & Laitman, 2007). These range from creating bubble nets as foraging tools, to using bubble clouds as a foraging technique, particularly evident in the Gulf of Maine population (Hain et al., 1982). These whales also employ bubbles for combat or as a distraction technique against predators (Sharpe & Dill, 1997;Wiley et al., 2011). ...
... These whales also employ bubbles for combat or as a distraction technique against predators (Sharpe & Dill, 1997;Wiley et al., 2011). Male humpback whales specifically use bubble trails as visual signals to lure females or as a warning signal to conspecifics, indicating aggression, distress, or aversion (Hain et al., 1982;Sharpe & Dill, 1997;Wiley et al., 2011). ...
... While this study supports our hypothesis that bubble blasts are used for buoyancy regulation, it is possible that there are alternate or additional functions for this behavior. One alternate theory is that bubble blasts are used for prey manipulation, akin to how humpback whales (Megaptera novaeangliae) use bubbling to corral prey (Hain et al., 1982). While this theory is possible, gray whales are not engulfment foragers, and they do not appear to chase their prey after producing a bubble blast nor do they aim the bubble towards the location where they ultimately feed ( Figure 2). ...
Foraging efficiency is key to animal fitness. Consequently, animals evolved a variety of kinematic, morphological, physiological, and behavioral adaptations for efficient locomotion to reduce energy expenditure while moving to find, capture, and consume prey. Often suited to specific habitat and prey types, these adaptations correspond to the terrain or substrate the animal moves through. In aquatic systems, adaptations focus on overcoming drag, buoyancy, and hydrostatic forces. Buoyancy both benefits and hinders diving animals; in particular, shallow divers constantly contend with the costs of overcoming buoyancy to dive and maintain position. Pacific Coast Feeding Group (PCFG) gray whales forage in shallow habitats where they work against buoyancy to dive and feed using various foraging tactics. Bubble blasts (underwater exhalations) have been observed during several foraging tactics performed by PCFG whales. As exhalations aid buoyancy regulation in other diving animals, we hypothesize that bubble blasts are performed by longer, more buoyant whales in shallower water and that bubble blasts increase dive duration while accounting for size and tactic. We test our hypotheses using Bayesian linear mixed effects models and a 7‐year dataset of drone footage containing concurrent individual morphological and behavioral data. We find that while headstanding – a stationary, head‐down tactic – bubble blasts are performed by longer, more buoyant whales and extend the dive duration, whereas whales using forward‐swimming tactics are less likely to bubble blast. Our results suggest that PCFG gray whales may use bubble blasts as a behavioral adaption to mitigate the cost of energetically expensive tactics in their shallow habitat foraging niche.
... The study results revealed that the exceptional design of the humpback whale flippers with protuberance LE, enables it to maintain a higher lift coefficient at higher angles of attack by allowing flow to remain attached, thus resulting delay in stall [9,10]. Thus the humpback whale is capable of performing tight turning maneuvers as a part of its feeding cycle [11][12][13]. The radius of such turns is inversely proportional to the amount of lift generated therefore any potential increment in lift is favorable [14]. ...
Some humpback whales from the Northwestern Atlantic population forgo migration to the Caribbean, spending winter months feeding along the U.S. mid‐Atlantic coast. We studied the foraging behavior of these whales at the mouth of the Chesapeake Bay, Virginia during winter from 2017 to 2022. While shipping channels here reach depths of up to 30 m, most of the area is 11–15 m deep. This shallow‐water environment poses physical constraints on classical humpback whale feeding modes. We deployed 20 digital acoustic tags (DTAGs) on humpback whales and identified foraging lunges from accelerometer data, detecting 788 lunges from 10 animals. Tagged whales averaged a single lunge per dive, lunging primarily in a horizontal orientation, with limited maneuvering compared to other study sites. Our results indicate that some elements of humpback whale foraging behavior are conserved across environments, but that the shallow depths in our study area constrain how animals are able to feed. The relatively high lunge rates we observed suggest this area is an important foraging ground. However, foraging in shipping channels increases the risk of ship strikes, which frequently occur in this area.
To capture prey more efficiently, cetaceans can display a wide range of foraging tactics to separate individual prey. Barrier feeding tactics are performed to restrict prey movements, using natural and non-natural barriers and some species can even create barriers with their own bodies. Mud ring feeding has been observed in bottlenose dolphins in Florida Bay and in Chetumal-Corozal Bay, where ring-maker dolphins create ring-shaped mud plumes to encircle fish schools. Here, we document for the first time Guiana dolphins performing the mud ring feeding behaviour in the Cananéia estuarine system, in the southern portion of the state of São Paulo, Brazil. A total of 11 dolphins were recorded in four expeditions through aerial footage engaging in the behaviour. These findings expand our knowledge about the behavioural plasticity of the species and builds upon existing records of mud ring feeding behaviour in cetaceans.
The field of wind energy stands at the forefront of sustainable and renewable energy solutions, playing a pivotal role in mitigating environmental concerns and addressing global energy demands. For many years, the convergence of nature-inspired solutions and wind energy has emerged as a promising avenue for advancing the efficiency and sustainability of wind energy systems. While several research endeavors have explored biomimetic principles in the context of wind turbine design and optimization, a comprehensive review encompassing this interdisciplinary field is notably absent. This review paper seeks to rectify this gap by cataloging and analyzing the multifaceted body of research that has harnessed biomimetic approaches within the realm of wind energy technology. By conducting an extensive survey of the existing literature, we consolidate and scrutinize the insights garnered from diverse biomimetic strategies into design and optimization in the wind energy domain.
Meristic characteristics of sand lance taken from Stellwagen Bank indicated the species to be the American sand lance,Ammodytes americanus.Bottom trawl data, ichthyoplankton surveys, and diver and submersible observations demonstrated a significant increase in relative abundance of sand lance since about 1975 on Stellwagen Bank; this trend was typical of the Northwest Atlantic from Cape Hatteras, N.C., to the Gulf of Maine. School shapes were constant in appearance, vertically compres sed, tightly compacted, and bluntly linear from a dorsal and ventral view. School strengths varied from about 100 to tens ofthousands ofindividuals with the nearest-neighbor distance ranging from '4 to 1'h body lengths. The swimmingmotion issinusoidal in form and eellike in appearance. Swimmingspeeds varied from 15 to over 120 cm/s. Copepods were the most important food source, constituting 41% ofthe total weight offood consumed; sand lance feed in school fonnation between midwater and the surface. Sand lance bury themselves totally or partially in clean sandy substrates when not schooling.
Distinct behavioral differences were noted from aerial observations of four species of baleen whales (Eubalaena glacialis, right whale; Balaenoptera borealis, sei whale; Megaptera novaeangliae, humpback whale; Balaenoptera physalus, finback whale) feeding together on 30 April and 1 May 1975. The right and sei whales fed together on patches of plankton. Right whales fed steadily with mouths open in the densest areas, while the sei whale followed a faster but more erratic path through the patches, alternately opening and slowly closing its mouth with slight throat distension at each closing. Humpback and finback whales fed together on dense schools of fish associated with the patches of plankton. The humpback fed by rushing, generally from below the schools of fish, while finback feeding was by more horizontal passes sometimes characterized by sharp turns and rolls within the fish schools and often with enormous throat distension.
Humpback whales (Megaptera novaeangliae) were observed and photographed during winter, 1974 near the West Indies and summer, 1976 near Newfoundland. Prior investigations on whale locomotion based on anatomical inference or surface observations did not describe any specific underwater use of the humpbacks' uniquely long flippers. Our results show that humpbacks achieve a high degree of maneuverability underwater through the active coordinated use of their flippers. Three-dimensional active movements including protraction-retraction, abduction-adduction, and lateral-medial rotations, were observed. The whales could move themselves in all directions independent from fluke-generated forward motion by thrusting with their resilient flippers. At higher swimming speeds (>4 knots) the flippers were used to effect sharply executed ascending or descending banked turns. Analysis of filmed sequences from three adult-calf encounters indicated a reduction of the amplitude and frequency of tailbeats by the adults; calves made tailbeats 4 to 7 times more frequently than adults when maintaining the same speed. The tail and flukes are forcefully moved other than vertically during maneuvering. The significance of these findings is discussed in relation to our knowledge of larger whales.
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