How Humpback Whales Create Bubble-Nets to Catch Fish

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The Basics of Bubble-Net Feeding

Bubble-net feeding is a sophisticated hunting technique employed primarily by humpback whales (Megaptera novaeangliae). This behavior involves one or more whales swimming in a spiral pattern beneath a school of fish while releasing air from their blowholes. The released air forms a cylindrical wall or “net” of bubbles that rises toward the surface, effectively corralling prey fish into a concentrated mass. As fish tend to avoid swimming through bubble curtains, they become trapped within this cylinder. The whales then swim upward through the center of this bubble net with their mouths wide open, engulfing thousands of fish in a single gulp. This technique is particularly effective for capturing small schooling fish like herring, krill, and capelin that might otherwise easily escape these massive predators.

The Discovery and Documentation of Bubble-Netting

Humpback Whales 'Bubble-Net' Feeding — Humpback Whales ‘Bubble-Net’ Feeding. Image by Openverse.

Scientists first documented bubble-net feeding in the 1920s, but the complexity of this behavior wasn’t fully appreciated until underwater filming and acoustic monitoring became possible decades later. Charles “Flip” Nicklin, a renowned National Geographic photographer, captured some of the first comprehensive underwater footage of this behavior in Southeast Alaska during the 1970s and 1980s. His work revealed the intricate coordination between multiple whales during cooperative hunts. More recently, drone technology has provided unprecedented aerial views of these feeding events, allowing researchers to map the precise movements and roles of individual whales. In 2018, researchers in Alaska used synchronized underwater cameras and acoustic recording devices to create detailed 3D models of bubble-net formation, further enhancing our understanding of this remarkable behavior.

The Science Behind Bubble Formations

The physics of bubble-net feeding involves principles of fluid dynamics and animal behavior. When a humpback whale exhales underwater, the released air forms bubbles that rise due to their buoyancy. As these bubbles ascend, they create localized upwelling currents and acoustic disturbances. Research by marine biologists has shown that the bubbles reflect sound in ways that confuse the lateral line system of fish—sensory organs that detect pressure and movement in the surrounding water. Additionally, the bubbles create a visual barrier that fish are reluctant to cross. Studies using computational fluid dynamics have demonstrated that the spiral pattern of bubble release creates a stable cylindrical structure that maintains its integrity as it rises through the water column. The effectiveness of this technique depends on precise control of bubble size, density, and placement—showcasing the whales’ remarkable mastery of their underwater environment.

Specialized Roles in Group Bubble-Netting

Group bubble-netting represents one of the most sophisticated examples of cooperative hunting among marine mammals. Research conducted in Southeast Alaska has identified specific roles that individual whales adopt during these coordinated hunts. Some whales serve as “bubble-blowers,” creating the cylindrical net, while others position themselves as “shepherds” that drive fish toward the net. Scientists have observed that certain whales consistently take on the same roles during repeated feeding events, suggesting specialization based on individual skills or experience. A groundbreaking study published in Royal Society Open Science in 2019 used digital acoustic recording tags (DTAGs) to track the movements of multiple whales during cooperative feeding. The data revealed that these roles aren’t random but represent a true division of labor that enhances hunting efficiency. Perhaps most remarkably, researchers have identified specific vocal signals that appear to coordinate the timing of these hunts, with distinctive calls marking the beginning of bubble release and the moment to surge upward through the concentrated prey.

The Unique Vocalization Aspect

Vocalizations play a crucial role in successful bubble-net feeding. Researchers using hydrophones have recorded specific feeding calls that precede and accompany bubble-net formation. A study published in Scientific Reports in 2018 identified a distinct “upward-sweep” call that appears to signal the start of coordinated feeding lunges. This call increases in frequency from about 500 Hz to 1,700 Hz over approximately 3-4 seconds. Intriguingly, this call may serve a dual purpose. Beyond coordinating the whales’ movements, scientists hypothesize that these vocalizations might also help concentrate prey. The sound waves could potentially create a “wall” of sound that further discourages fish from escaping the bubble net. Some researchers even suggest that certain calls may specifically startle or disorient prey, making them easier to capture. These feeding-specific vocalizations differ significantly from the complex songs humpbacks are famous for, which are primarily associated with breeding behavior rather than feeding.

Anatomical Adaptations for Bubble-Netting

Humpback whales possess several anatomical features that make bubble-net feeding possible. Their baleen plates—the keratin structures that hang from their upper jaws—function as efficient filters, allowing them to strain small prey from massive volumes of water. Each humpback has between 270-400 baleen plates that can measure up to 3 feet long. Additionally, humpbacks have evolved expandable throat pleats (ventral grooves) that allow them to dramatically increase their mouth volume when feeding. These pleats can expand to hold up to 15,000 gallons of water and prey in a single gulp. The humpback’s flippers, the longest of any whale species relative to body size (reaching up to 15 feet), provide the maneuverability necessary for creating precise bubble formations. Perhaps most crucial for bubble-netting is the specialized structure of their blowholes, which allows for controlled release of air underwater—a feature not equally developed in all cetacean species. These adaptations collectively enable the sophisticated hunting technique that has become their signature feeding strategy in certain regions.

Regional Variations in Bubble-Netting Techniques

Interestingly, not all humpback whale populations practice bubble-net feeding, and those that do often display regional variations in technique. In Southeast Alaska’s Frederick Sound and Chatham Strait, researchers have documented large cooperative groups of up to 20 whales participating in coordinated bubble-netting. In contrast, bubble-netting in the Gulf of Maine typically involves smaller groups of 2-4 whales. Humpbacks in Norwegian waters have been observed using a variation called “carousel feeding,” where they herd herring into tight balls using bubbles before slapping their tails to stun the fish. In Antarctica, some humpbacks employ a modified technique called “flick feeding,” combining bubble curtains with rapid movements of their massive flukes to concentrate krill. These regional differences appear to be culturally transmitted rather than genetically determined, as young whales learn these techniques through observation of experienced adults. This represents a form of cultural evolution, where successful feeding innovations spread through whale populations over time.

The Role of Learning and Cultural Transmission

Bubble-net feeding is not an innate behavior but rather a learned technique passed down through generations of humpback whales. Young calves observe their mothers and other adults performing this complex hunting strategy during their first years of life. Research by marine biologists Jenny Allen and Ellen Garland has documented the gradual acquisition of bubble-netting skills, with juvenile whales initially making simple attempts before mastering the sophisticated coordination required for effective feeding. This represents one of the clearest examples of cultural transmission in marine mammals. Studies tracking individual whales over decades have shown how feeding innovations can spread through populations, creating distinct “feeding cultures” in different regions. For example, a technique called “lobtail feeding,” which combines bubble-netting with tail slaps, first appeared in the Gulf of Maine in 1980 among a few individuals but spread to over 40% of the population by 2010. This cultural learning process highlights the remarkable cognitive abilities of humpback whales and challenges traditional distinctions between human and animal cultural development.

The Effectiveness of Bubble-Net Feeding

Bubble-net feeding represents an extraordinarily efficient hunting strategy. Research using underwater cameras and prey-sampling techniques has estimated that a single coordinated feeding lunge by a group of humpbacks can capture up to 30,000 fish. This equates to approximately 100,000 calories per lunge—a significant return on the energy invested in the hunting technique. Studies measuring the caloric content of captured prey have shown that during peak feeding season in productive areas like Southeast Alaska, humpbacks can consume up to 1.5 tons of fish daily using bubble-netting techniques. This efficiency is particularly important for these massive mammals, which must build substantial blubber reserves during summer feeding seasons to sustain themselves during long migrations to tropical breeding grounds, where they typically fast for months. Comparative studies of feeding efficiency have shown that cooperative bubble-netting can be up to four times more effective than solitary lunge feeding techniques, highlighting the evolutionary advantage of this sophisticated behavioral adaptation.

Threats to Bubble-Netting Populations

A stunning capture of a humpback whale breaching in the ocean, showcasing marine wildlife. — Humpback whale. Image via Pexels.

Despite the effectiveness of bubble-net feeding as a hunting strategy, humpback whales face several threats that could impact this behavior. Climate change is altering the distribution and abundance of prey species like herring and krill, potentially disrupting traditional feeding areas. A 2020 study published in Global Change Biology documented shifts in humpback feeding grounds in the Gulf of Maine correlating with changing water temperatures and prey distribution. Ocean noise pollution from shipping, seismic exploration, and military sonar can mask the vocalizations crucial for coordinating bubble-net feeding. Research has shown that ambient noise levels in some marine environments have doubled each decade since the 1960s, potentially interfering with the acoustic coordination necessary for successful cooperative hunting. Additionally, entanglement in fishing gear poses a direct threat to bubble-netting whales, which feed in productive coastal areas often heavily used by commercial fisheries. While global humpback populations have largely recovered from historical whaling, these contemporary threats could impact the cultural transmission and practice of their most sophisticated feeding techniques.

Observing Bubble-Netting in the Wild

For wildlife enthusiasts, witnessing bubble-net feeding represents one of nature’s most spectacular displays. The best locations for observing this behavior include Southeast Alaska (particularly Frederick Sound, Chatham Strait, and Icy Strait) during the summer months of June through September, when humpbacks concentrate in these productive feeding grounds. Tour operators in Juneau, Sitka, and Petersburg offer specialized whale-watching excursions focused on finding bubble-netting groups. The first signs of bubble-netting activity typically include birds circling and diving as they attempt to snatch fish escaping the whales’ bubble traps. Observers might then notice circular patterns of bubbles appearing at the surface, followed by the dramatic sight of multiple massive whale mouths simultaneously emerging through the center of these bubble circles. Responsible whale watching requires maintaining appropriate distances (NOAA guidelines recommend staying at least 100 yards away) and minimizing vessel noise that might disrupt feeding behavior. For photographers, the predictable nature of bubble-net feeding—once a group begins, they typically continue for multiple feeding lunges in the same area—provides rare opportunities to capture this remarkable behavior.

Recent Scientific Discoveries

Two humpback whales. Photo by Elianne Dipp, via Pexels.

Our understanding of bubble-net feeding continues to evolve with new research technologies. A groundbreaking 2021 study published in the Proceedings of the National Academy of Sciences used synchronized drone footage, underwater acoustics, and animal-borne sensors to create detailed three-dimensional models of bubble-net formation. This research revealed previously unknown precision in the whales’ movements, showing that they adjust the timing and angle of their spiral swimming patterns based on prey density and current strength. Another recent discovery involves the identification of specialized “architect” whales that consistently initiate bubble-net formation in certain groups. These individuals appear to possess greater experience or skill in assessing prey distribution and coordinating group movements. Genetic studies are exploring whether certain bubble-netting techniques might correlate with matrilineal lines, suggesting potential heritable components to learning capacity for complex feeding behaviors. Additionally, new acoustic research is decoding the subtle variations in feeding calls that may communicate specific instructions about timing and positioning to other group members, further highlighting the sophisticated communication underlying this remarkable behavior.

Conclusion: Nature’s Ultimate Fishing Strategy

Whales — Humpback whale in the NOAA Stellwagen Bank National Marine Sanctuary with a bubble net. Image by NOAA, Public domain, via Wikimedia Commons

Bubble-net feeding stands as one of the most remarkable examples of behavioral sophistication in the animal kingdom, showcasing the extraordinary intelligence and social complexity of humpback whales. This hunting strategy represents a perfect convergence of physical adaptation, cognitive ability, social cooperation, and cultural learning that has evolved to maximize feeding efficiency in challenging marine environments. The continued study of bubble-netting provides valuable insights not only into cetacean behavior but also into the evolution of cooperative strategies and cultural transmission across species. As climate change and human activities increasingly impact marine ecosystems, protecting the habitats and prey resources that support this behavior becomes essential for preserving one of nature’s most impressive hunting techniques. In the graceful spiral of bubbles rising through blue waters and the perfectly synchronized emergence of massive cetacean mouths, we witness not just an effective fishing strategy, but a profound demonstration of the capabilities of non-human minds to solve complex problems through cooperation and innovation.

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