The sea is quiet, revealing nothing of the activity going on below the surface. Suddenlyl a rush of displaced water and whale blows signals nearly two dozen Northeast Pacific Ocean humpback whales lunging above the surface while cooperatively bubble netting for a meal of herring. As the whales sounded for the depths to commence another cooperative bubblenet, I counted a minimum of 19 humpback whale tail flukes in this cooperative feeding pod. Providing the perfect SE Alaskan backdrop, the icy jagged peaks of stunning Baranof Island can be seen to the west of the whales.
Herring was schooling in immense shoals in Tebenkof Bay along Kuiu Island in South Chatham Strait. Uncountable numbers of the eight-inch fish were making the water roil. Tiny ripples made by swirling herring kept hitting the surface from the depths, creating a sound akin to the gentle pattering of rain. A clean, briny scent filled the air that bespoke the presence of immense numbers of bait fish near the surface. I was not the only one noticing this bounty. The whales were also aware of the abundant herring.
Conditions were nearly perfect with clear blue skies, soft sunlight glittering off of the sea and great numbers of humpback whales feasting on herring. Only a riffle of wind stirred the surface of the water. Some humpback whales worked alone but what I hoped to see was cooperative bubble net feeding. While humpback whales employ bubbles worldwide to feed on prey, in SE Alaskan waters some humpback whales have adapted a unique strategy of cooperatively hunting herring incorporating individually unique feeding calls, bubbles and coordinated synchronous lunging. Deploying a hydrophone over the edge of the boat I heard the screeching calls of humpback whales coordinating their feeding lunges on herring from the depths below the boat.
Click onto the link to hear a sample of an underwater humpback whale cooperative bubblenet feeding call (Thanks to Captain Dennis Rogers and Alaska Sea Adventures for use of this feeding call.)
Each whale appears to have an assigned roll in cooperative bubble netting. Some create ascending calls plus trumpeting blasts heard on the hydrophone as well as through the hull of the boat while other whales in the group produce a ringed curtain of bubbles to entrap the herring. On a signal, the humpbacks lunge to the surface en masse through the curtain of bubbles, their immense jaws gaping and ventral throat pleats grossly distended with seawater and herring as the whales rise above the surface of the sea. I’m always reminded of black mussels when I see these giant maws rocketing out of the surface of the ocean.
For this whale geek, observing cooperative bubble net feeding behavior is akin to finding the Holy Grail. Seeing a ring of bubbles rise to the surface only to be followed by lunging humpback whale maws amidst frantically escaping herring is a sight whale watchers hope to view on the whales’ feeding areas. Over the days I spent in Tebenkof Bay, I witnessed c. 75 cooperative bubble nets in our immediate vicinity while other groups of whales could be seen in the distance bubble netting from time to time. The groups we observed ranged in numbers from 8-10 individual humpbacks to just under two dozen.
Interestingly, when the humpbacks surface for deep lusty breaths, one often hears excited trumpeting and deep elephant-like groans and growls.
There is evidence suggesting that one whale in particular is always the first whale to dive down and there is always one whale in particular that is the last whale to dive. When the last whale is down, get your cameras ready for within 20 seconds or sometimes a minute or more, the whales generally lunge to the surface somewhere in the nearby vicinity. From our observations it seemed as if certain whales always showed up in the same positions in the organized chaos of the bubble nets.
University of Hawaii-Hilo onboard whale researcher professor Dr. Adam Pack is studying the longevity of cooperative bubble netting associations within the SE Alaska bubble netting groups and how long these associations persist. First documented in the early 1980s by the Kewalo Basin Marine Mammal Laboratory in Honolulu, now known as The Dolphin Institute , Dr. Pack is studying the length of these cooperative bubble netting associations and whether any of these associations persist within the Hawaiian wintering grounds. Dr. Pack spent many hours on the deck of our boat photographing whale tail flukes as the whales dived. Each evening he worked on matching current documentations of humpback whale tails to the catalog of documented photographed whale flukes.
For those of you interested in an excellent online tool for identifying the Alaska/Hawaii population of humpback whales, click onto the Northeast Pacific Ocean Humpback Fluke Identification Catalog . Using this catalog one may be able to identify humpback whale tails you have photographed in either Alaska or Hawaii. For instructions on how to contribute your own fluke identification photos, please visit the Fluke ID Catalog Home Page
Finally, the following short video represents why I adore humpback whales. Please forgive my humble, awkward attempts to create video footage of the whales. I think I need a proper HD video camera plus a non-rocking boat in addition to videographraphy lessons. Next time I’ll stick to a DSLR but in the meantime, please enjoy this tribute to my favorite big beasties of the deep.
Tebenkof Bay along Kuiu Island in South Chatham Strait, The Inside Passage, SE Alaska, USA
July 8, 2010
Canon 7D, Canon 100-400mm lens, shutter 1/2000, f/6.3, exposure bias +0.33, shutter priority, focal length 100mm, ISO 400