Whale 2016 05 05
Image: Worman Sportsfishing

Not what you'd expect to see bursting maw gaping from the waters beneath a busy marina! Yet the residents of Knudson Cove in Ketchikan, Alaska have witnessed these majestic humpback whales emerging several times over the last week ... and the ocean giants certainly know how to make an entrance!

"The whales this spring have been putting on stunning performances for the local boat captains," writes the team from Worman Sportsfishing, who shared their footage online.

The humpback whales (Megaptera novaeangliae) that gorge themselves in the bountiful seas of Alaska spend their winters in warmer climates. In the tropical temperatures off the coast of Hawaii, the whales get together to breed, and during this time, females will often give birth to their calves, after long gestation periods.

Even as newborns, the calves weigh in at a hefty 900 kilograms (that's around one ton or 2,000lbs), so mom needs to consume a huge amount of tiny marine life to sustain them both (and yes, whales breastfeed underwater!). As the seasons change, humpbacks begin their long journey back to the frigid but food-rich waters off the Alaskan coast, and by April and May, many are starting to arrive.

"The whales have been in the cove over the last week," Chasina Worman tells us. "So while they were not entirely unexpected, a large whale coming that close is always an amazing, shocking experience."  

The humpbacks seem to have taken a real liking to the waters surrounding Knudson Cove  and the irresistible bounty of food to be found there probably has something to do with that.

The "wall" of bubbles you see here is part of a feeding strategy known as bubble-netting. The whales expel air underwater while swimming in a spiral towards the surface before rising up to engulf the shoal of fish they've trapped within.

The bubbling behaviour is often used by other cetaceans, too. Fish caught in the trap will not pass through the bubbling wall, which makes this the perfect tactic for herding the fish, blocking escape routes and lassoing a good meal. 


Top header image: J. Maughn, Flickr