Chatham Strait, Alaska
Who could have invented such bizarre behavior? What animal, other than perhaps man, could organize others of his species to work in perfect unison for the common good?
Group lunge feeding by humpback whales, with the deployment of a “net” of bubbles to concentrate their prey, is truly a remarkable spectacle. We saw this miracle today, watching as the preparatory breathing by the whales took place, then the sequential diving, and finally the upward lunging. For over two hours we cheered with delight. Our minds are still racing to understand it. The choreography has to be perfect, the timing exact and the results productive. Otherwise Megaptera novaeangliae – the “big-winged New Englander” – would have abandoned this practice long ago.
It is just in the past few years that researchers have begun to understand humpback bubble netting. Hours of observations from small boats and the use of video cameras, some attached harmlessly to the participant whales, have allowed scientists to describe the sequence of events. Our bubble-netting group included at least 12 individuals. One animal – we’ll call that individual the star of the show – descends first, perhaps to 100 feet or more. The others follow. The star then ascends slowly in a spiral, emitting bursts of bubbles from its paired blowholes. Large bubbles break up into myriad smaller bubbles as pressure decreases toward the surface. A circular veil of tiny bubbles corrals the targeted immature herring. They panic and scurry into a tight ball within the net. The trap is set.
Each time this cooperative group dove we lowered the ship’s hydrophone, and quickly learned to associate a series of loud moans from one of the whales (the star?) as our signal to raise our cameras. However, we had to predict just where the explosion of huge, open mouths, all tightly packed within the perimeter of the net, would explode to the surface. By about the 10th dramatic lunge we became fairly accurate at predicting, especially since a pod of Dall’s porpoises, also feeding on the panicked herring, but at the surface, were a sure indicator. Our photos will be terrific!
It was a smashing first day. Cruising slowly in Chatham Strait, Captain Scott Martin spotted distant dorsal fins. Killer whales before breakfast! This was a pod of 6 or 7 “transients” – killer whales that are known to prey on other marine mammals. (The “residents” feed almost exclusively on salmon). We identified one adult male as T61, an animal of at least 35 years of age and one that is known to associate with a variety of other transients. They entertained us right through breakfast, at one point passing directly under our drifting ship. The mind-boggling humpback encounter followed, and the afternoon was then spent exploring a majestic forest and one of the many salmon streams on Baranof Island. Hundreds, maybe even thousands of pink and sockeye salmon filled the deep holding pools of this stream. Some of these fat-rich fish would not make it over a small cascade to the clean gravel beds from which they hatched. Brown (grizzly) bears were patrolling the stream and had been here just before us. Sundry fish parts were strewn on the rocks. Massive bears have little difficulty in snatching up these delicious morsels as they struggle upstream. We noticed that the tops of most of the salmon heads were missing; fatty brain tissue is a delicacy for bears. Eagles, ravens, crows, gulls, river otters, mink and other vertebrates will soon be there to clean things up and to grow. The cycle continues.
Who could have invented such bizarre behavior? What animal, other than perhaps man, could organize others of his species to work in perfect unison for the common good?
Group lunge feeding by humpback whales, with the deployment of a “net” of bubbles to concentrate their prey, is truly a remarkable spectacle. We saw this miracle today, watching as the preparatory breathing by the whales took place, then the sequential diving, and finally the upward lunging. For over two hours we cheered with delight. Our minds are still racing to understand it. The choreography has to be perfect, the timing exact and the results productive. Otherwise Megaptera novaeangliae – the “big-winged New Englander” – would have abandoned this practice long ago.
It is just in the past few years that researchers have begun to understand humpback bubble netting. Hours of observations from small boats and the use of video cameras, some attached harmlessly to the participant whales, have allowed scientists to describe the sequence of events. Our bubble-netting group included at least 12 individuals. One animal – we’ll call that individual the star of the show – descends first, perhaps to 100 feet or more. The others follow. The star then ascends slowly in a spiral, emitting bursts of bubbles from its paired blowholes. Large bubbles break up into myriad smaller bubbles as pressure decreases toward the surface. A circular veil of tiny bubbles corrals the targeted immature herring. They panic and scurry into a tight ball within the net. The trap is set.
Each time this cooperative group dove we lowered the ship’s hydrophone, and quickly learned to associate a series of loud moans from one of the whales (the star?) as our signal to raise our cameras. However, we had to predict just where the explosion of huge, open mouths, all tightly packed within the perimeter of the net, would explode to the surface. By about the 10th dramatic lunge we became fairly accurate at predicting, especially since a pod of Dall’s porpoises, also feeding on the panicked herring, but at the surface, were a sure indicator. Our photos will be terrific!
It was a smashing first day. Cruising slowly in Chatham Strait, Captain Scott Martin spotted distant dorsal fins. Killer whales before breakfast! This was a pod of 6 or 7 “transients” – killer whales that are known to prey on other marine mammals. (The “residents” feed almost exclusively on salmon). We identified one adult male as T61, an animal of at least 35 years of age and one that is known to associate with a variety of other transients. They entertained us right through breakfast, at one point passing directly under our drifting ship. The mind-boggling humpback encounter followed, and the afternoon was then spent exploring a majestic forest and one of the many salmon streams on Baranof Island. Hundreds, maybe even thousands of pink and sockeye salmon filled the deep holding pools of this stream. Some of these fat-rich fish would not make it over a small cascade to the clean gravel beds from which they hatched. Brown (grizzly) bears were patrolling the stream and had been here just before us. Sundry fish parts were strewn on the rocks. Massive bears have little difficulty in snatching up these delicious morsels as they struggle upstream. We noticed that the tops of most of the salmon heads were missing; fatty brain tissue is a delicacy for bears. Eagles, ravens, crows, gulls, river otters, mink and other vertebrates will soon be there to clean things up and to grow. The cycle continues.
