You hear it before you see it. A hiss of air breaking the surface, then a ring of bubbles appears, 25 yards across, expanding outward in a near-perfect circle. The water inside the ring goes dark. Shadows rise.
Boom.
The surface explodes. Mouths the size of pickup trucks burst upward through the center of the ring, wide open, pleated throats ballooning with seawater and herring. Five, six, seven whales at once. Tiny fish leap in every direction. The sound is part freight train, part waterfall.
The gulls go crazy.
And then it’s over. The whales slide back under. They blow a few times, the stench of half-digested herring drifting across the boat, and one by one they arch their backs and dive. The whole thing lasted maybe eight seconds.
Now we wait.
Again.
I’ve watched this happen hundreds of times across five seasons running our Hungry Whales Photo Tour in Southeast Alaska, and it still stops me cold. Bubble-net feeding is, without exaggeration, one of the most sophisticated cooperative hunting strategies in the animal kingdom. And it happens right here, in the cold green water off Sitka, every spring.
What Is Bubble-Net Feeding?
Bubble-net feeding is a coordinated hunting technique used by humpback whales to corral and concentrate schooling fish, primarily herring, before lunging through the trapped prey as a group.
The basic mechanics: one or more whales dive beneath a school of fish and begin releasing air from their blowholes while swimming in a circle or upward spiral. The bubbles rise to the surface in a cylindrical curtain. Fish won’t cross the bubble barrier. As the net tightens, the prey is compressed into an increasingly dense ball. Then the whales lunge upward through the center of the net, mouths agape, engulfing thousands of fish in a single pass.
It sounds simple. It is not.
A Learned Behavior, Not Instinct
This is important: bubble-net feeding is not hard-wired. It’s a learned, culturally transmitted behavior. Not every humpback whale population on earth knows how to do it. As first documented by Charles and Virginia Jurasz during twelve years of observation in Southeast Alaska’s Lynn Canal and Frederick Sound, humpback whales here developed and passed on this technique within specific social groups (Jurasz & Jurasz, 1979, Scientific Reports of the Whales Research Institute).
That 1979 paper was the first formal description of the behavior, though Norwegian whaler Morten Ingebrigtsen reported something similar in the Norwegian Sea back in 1929. The Jurasz family watched whales repeat bubble-net feeding events over five hours, 24 times in a single session, all while vocalizing underwater.
The Southeast Alaska population has been refining this for decades. It’s cultural knowledge, passed whale to whale.
What’s Actually Happening Underwater
From the surface, you see the bubble ring and the lunge. Underneath, it’s far more complex.
In 2011, researchers David Wiley, Colin Ware, and their team used digital acoustic recording tags (DTAGs) attached to feeding humpbacks to map the underwater mechanics for the first time. They identified two distinct techniques: the “upward-spiral” and the “double-loop” (Wiley et al., 2011, Behaviour).
In the upward-spiral, a whale dives to roughly 20-35 meters, begins a clockwise spiral, and releases a continuous stream of bubbles as it corkscrews upward. The average spiral involves about two full revolutions over 70 seconds. As the whale ascends, it increases its rate of turn, tightening the spiral and compressing the prey into the upper portion of the net.
The double-loop is a three-step sequence. First, the whale performs a deep “corral-loop” at around 21 meters to establish the initial bubble boundary. Then it surfaces and slaps the water with its flukes, a behavior called lobtailing. Then it dives again for a shallower, faster “capture-loop” at about 13 meters, roughly the body length of an adult humpback, before lunging up through the concentrated prey.
Individual whales tend to favor one technique or the other. But Wiley’s team also documented a whale that combined both, using an upward-spiral to form the corral-loop before switching to the double-loop capture sequence. Different animals accomplish the same task in different ways. That’s behavioral plasticity, and it’s a hallmark of intelligence.
Tool Use
In 2024, a team led by Andy Szabo of the Alaska Whale Foundation took this research further, using drone footage and animal-borne video cameras to study solitary humpback whales bubble-net feeding in the same waters of Southeast Alaska. Their findings, published in Royal Society Open Science, argued that bubble-nets qualify as manufactured tools, placing humpback whales among a very small group of animals that both create and modify tools for hunting (Szabo et al., 2024).
The study found that solitary whales actively controlled the number of rings within a net, the net’s size and depth, and the horizontal spacing between bubbles. By adjusting these elements, a whale could increase its prey intake per lunge by an average of seven times compared to whales feeding without nets, with no measurable increase in energy expenditure.
Seven times the food for the same effort. That’s not random behavior. That’s engineering.
Pectoral Herding: Using Flippers to Funnel Prey
Bubble-nets aren’t the only trick in the toolbox. In 2019, Madison Kosma and colleagues at the University of Alaska Fairbanks documented a previously undescribed behavior they named “pectoral herding” (Kosma et al., 2019, Royal Society Open Science).
After deploying a bubble-net, certain whales were observed using their enormous pectoral fins, which can reach a third of the whale’s body length, to further condense prey before lunging. The fins serve three functions: creating a physical barrier to block escape, generating water movement to direct fish toward the mouth, and using the white underside of the flipper to reflect light and startle prey upward.
Kosma’s team filmed this near salmon hatchery release sites along Baranof Island in Southeast Alaska, the same waters we work in during our whale photo tour. The whales had adapted their hunting to target juvenile hatchery salmon, a non-schooling species that doesn’t cluster as neatly as herring. The whales innovated. They changed their technique to match the prey.
What It Looks Like at 30 Feet
The science describes the mechanics. But nothing prepares you for the scale of it.
Last spring, we had seven whales feeding in a tight group right around our boat. They submerged about 30 feet away, vanished for a minute, and then came up to breathe immediately behind us. We were wet from the blow and gagging on the stench of dead herring. Gary, our captain, just laughed. He’s been on these waters his whole life, and he still grins like a kid every time it happens.
Some days the whales feed nonstop. Bubble ring after bubble ring, for hours. Other days you search. You read the water, look for birds working the surface, watch for the first puff of a blow on the horizon. The herring move, and the whales follow, and we follow the whales.
That uncertainty is part of it. This isn’t a zoo. These are wild animals making decisions in real time, deploying complex hunting strategies that researchers are still working to understand. Watching it unfold from the foredeck of a small boat is, without overstating it, one of the most extraordinary wildlife experiences on earth.
When and Where This Happens
Bubble-net feeding in Southeast Alaska is tied to the Pacific herring spawn. As herring aggregate in the waters around Sitka, Chatham Strait, and the surrounding channels each spring, humpback whales converge to feed. The peak activity typically falls in late March through early April, well before the summer tourist season.
That timing matters for photographers. Fewer boats on the water. Smaller crowds. And the most concentrated, intense feeding behavior of the year.
Our Hungry Humpbacks Photo Tour is built around this window. Five days on the water with Gary and a small group, positioned for the best bubble-net feeding photography Southeast Alaska offers. If you want to see this for yourself, and I mean really see it, not from the rail of a cruise ship, that’s what this trip is for.
Cheers
Carl
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