Southeast Alaska: Day 2, Stevens Passage and Dawes Glacier

Once aboard the Sea Lion and away from Juneau, we could cover a lot of territory on the ship. We moved south along the Stevens Passage, headed for the Tracy and Endicott Arms (fjords in the Tracy Arm-Fords Terror Wilderness.)  The crew likely got some sort of tip about whales, because we continued south until we found a group of humpback whales near Gambier Bay.

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Early whale sighting aboard the Sea Lion, 7:30 AM, August 1, 2016

These whales put on a great show, repeatedly diving and swimming by the ship, unconcerned (the officers had stopped the ship; we were essentially just drifting along, which is a pretty common safety measure among whale watching boats, although this was the largest ship I’ve been on to do this.)

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A humpback whale (Megaptera novaeangeliae) strongly arches its back as it goes for a deeper dive in the Stevens Passage, AK

The group of whales (pod) was relatively large, at least seven whales and possibly as many as ten. Humpbacks owe their name to one of two things, depending on who you believe. Either the name comes from the hump just ahead and under the dorsal fin, which can be seen in the photo above; or the name comes from their tendency to deeply arch their backs as they dive, giving them the appearance of a hunch, which can also be seen in the photo above. Wikipedia’s article on humpbacks mentions the arching of the back as the origin of the name, but does not provide a source.

The whales showed off a couple of great behaviors – tail slapping, also called lobtailing, which is bringing the fluke of the whale high out of the water and slapping it down on the surface to create a large splash and sound. It is not understood why the whales do this, but chances are that it’s a signal to other whales, the loud sounds created would carry well in the ocean and be a great way to signal whales that are far away from the slapper.

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A humpback tail slapping. If you look closely, you can see from the shape of the right hand side of this photo that it’s the belly (ventral surface) of the whale on that side. Underwater, this whale is belly-up to slap its flukes on the surface.

Last but not least, the humpbacks did breach at least twice, but I didn’t get a good photo. Caught by surprise (breaches can be over in just two seconds or so) I didn’t have the camera focused on the right place, and I wasn’t even trying to get a shot of the right whale.

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A little too off-center to be a good photo of a breach, and not enough resolution to crop just to the whale on the left. I had been intending to get another photo of the tail-slapping whale, whose splash can be seen in the upper right.

All the photos above were captured before 8:30 in the morning, so there was even more to see that day, which may have to wait for another post.

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