Humpback Whales’ Defensive Ring: How Crews Should Respond

Videos flash across WhatsApp groups, warnings crackle over night-watch radios, and scientists rush to authenticate what they are seeing. The pattern appears coordinated, unfamiliar and suddenly widespread.

When I first witnessed it, the early light was still spreading a bruised lilac colour across the sea, while diesel and rain-soaked rope scented the deck. Whales formed a circle between the net and a sheen of anchovies, their mouths just piercing the water and their flukes briefly visible in the swell. The crew went silent, as though a church had quietly arrived on board. Without intending to, I stopped breathing. The mate lowered the engine to a subdued hum. A calf moved into the light between two adults as other whales sent up a wall of bubbles, like a line being marked in the water. Then the circle drew closer.

The day the sea pushed back

Crews have named it “the wheel”, and nobody working these fishing routes recalls seeing this kind of display around fishing gear. Rather than fleeing in all directions, the whales gather together, turn towards the centre and slowly revolve, with calves and smaller animals protected within the formation. Along the outside, one or two adults break away to confront the approaching vessel, curving their bodies and striking the surface as though setting an invisible limit. It is not the exuberant turning associated with a feeding frenzy. This was not a feeding wheel - it was a barricade.

In late August, off northern Peru, a skipper recorded fourteen humpbacks forming a ring while his purse seine advanced over baitfish. They remained there for almost twelve minutes, then moved south as a compact group, guarding a calf like a security detail. One week afterwards, 600 nautical miles west, near the Line Islands, longline crews reported much the same event: a scattered flower-like arrangement of whales tightening whenever gear entered the water and relaxing once the hooks came back aboard. Scientists who independently examined the footage said the animals’ positions and spacing bore the hallmarks of cooperative defence rather than disorientation. “It’s intentional grouping,” one told me.

Why is this happening now? The explanation may partly lie in the untidy intersection of climate and commercial fishing. Warmer anomalies drive prey into deeper water or unfamiliar routes, bringing fleets after them-and whales too. When vessel traffic is heavy and workable periods are short, confrontations become more likely. Humpbacks are notably cultural animals, learning from one another and transmitting songs, migration routes and, indeed, new techniques. If gear presents the same persistent threat as a predator, whales could be trying a shared defence learned from encounters with orcas and modified for nets and lines. Social learning can sweep across a population like fire in dry grass. We may be seeing that behaviour propagate as it happens.

What to do when the ring appears

Captains who have avoided the most serious encounters use a straightforward procedure called the “quiet spiral”. Bring speed below 3 knots, select neutral and idle for 90 seconds, then travel in a broadening, slow circle that leaves the gear downwind and stays at least 200 metres from the whales’ outer edge. Pull in any loose line in the water, keeping lines vertical rather than trailing. Where a drone is available, fly it briefly for a minute to see whether calves are inside the formation. Then wait for a further twelve minutes. It can seem interminable, but it is not.

Impatience causes the usual errors. Attempting a rapid haul while whales are defending themselves keeps a vessel involved and increases the danger. Keep radio communications measured. Should setting be unavoidable, deploy shallow gear and be ready to abandon the operation at once. Dynamic avoidance is effective: altering course by one degree for one hour can protect an entire day’s work. Everyone knows the point at which a plan unravels and hands become tense around the winch controls. Give them time to settle. Let’s be honest: nobody really does that every day. Crews that have avoided incidents say they now regard the ring as they would a school zone: slower movements and more careful decisions throughout.

The equipment matters too. Highly visible buoys and quieter lines make it easier for whales to interpret the water column. Weak links designed to give way under a whale’s force can lessen injury if contact occurs. Some fleets are testing timed trap releases and acoustic systems that raise gear without a vertical rope. There is no need to refit an entire vessel before taking action. A single set of weak links and a laminated “quiet spiral” card beside the helm can alter onboard habits. No net is worth a whale’s life.

“The first time they formed up in front of us, I thought we were seeing some strange feed. Then I saw the calf inside. We backed off, ran the spiral, and they just… opened a door,” says Javier C., a captain with twenty seasons in the eastern Pacific.

• Reduce speed to under 3 knots and idle for 90 seconds before making any manoeuvre.
• Remain at least 200 metres from the outer ring, and recover slack so that lines stay vertical.
• Wait twelve minutes; if the ring remains, change course by one degree for one hour.
• Install weak links on vertical lines and use high-contrast buoys to improve visibility.
• Make a brief drone check for calves; when uncertain, remain clear and record the sighting.

The wider picture, and what it asks of us

The Pacific has long been an accounting book of exchanges: fish for time, miles for diesel, and reward for risk. This new whale formation adds another entry. It points to intelligence adapting under strain: a social defence beginning in one pod, copied by others and carried over thousands of kilometres through song and shadow. Coastal communities sense its significance as well. Island fishers, Māori and Polynesian navigators, and Chilean crews whose grandparents read the ocean through birds and swell all say that the ring signals a need to ease the pace of work, not a boundary to force through. If whales are changing the rules, we can change ours. Conditions will not always be ideal; there will be days when wind, quota and fortune clash. But modest, repeatable actions-the spiral, weak links and an hour of patience-can mean fewer injuries for both whales and people.