July 8 Endicott Arm

Monday July 8th — Endicott Arm

Yesterday we walked around Juneau prior to boarding the National Geographic Quest.  We hiked along the Gold Flume trail, which commemorates the channel they brought mountain water down into Juneau to process gold in the early days. It was a lovely walk and allowed us to refresh our binocular skills with several new bird species sightings. 

Our entire week long trip will be within the Tongass National Rain Forest, 17 million acres in size, the largest temperate rainforest in the US. 

The Quest traveled south overnight through Stephen’s Passage and into Holkham Bay towards the Tracy Arms-Fords Terrer Wilderness and within it the fjord of Endicott Arm. We were awakened at 6:15, a little earlier than expected, with an announcement that humpbacks had been seen bubble-net feeding up ahead. While it was a little off our planned route, the ship’s navigators diverted a bit to the south, into Frederick Sound and the Five Fingers Lighthouse.  Bubble-net feeding is an unusual cooperative behavior (humpbacks are solitary animals rather than family pods) where a team of whales corral more (in this case herring) into a tight space and then all the whales surface together, mouths open to catch as much food as possible. Humpbacks are baleen whales, meaning they have no teeth. So in this example they take in a huge volume of water as well as fish and then force the water back out through the filter of their baleen sheets. 

Humpbacks migrate to this area in the summer to feed, and then migrate south to Hawaii for the winter to breed and give birth. In general they do not eat during the southern half of their journey, and can lose up to a third of their body weight over the winter, particularly for nursing females. Of the thousands of humpbacks that summer in SE Alaska, only about 50 are known to exhibit the bubble-net feeding behavior.  We saw 10 whales today and watched for an hour as they surfaced every 1-4 minutes to feed repeatedly. They were so close we could see the bubbles and the fish—- something so rare that the naturalists onboard were stunned with delight.  

That was just the beginning of a warm and sunny day (also rare!) that included at least 30 harbor seals (many lying on small icebergs near Dawes glacier), a zodiac ride near a calving glacier, and riding the resulting swells from a large calving back to the ship. Endicott Arm is a 34 mile long fjord carved by the Dawes Glacier, which is now about 12 miles long and 1/2 mile wide. The fjord itself has walls 200 feet high and water 650 feet deep—- all 2650 feet (and 34 miles) were originally the glacier’s ice! As we waited for our turn to go out in the Zodiacs, small ice floes from the glacier floated past the ship, several of them carrying sunbathing harbor seals. 

Pictures: humpbacks surfacing for a bubble-net feast, harbor seals, Glaucous-winged Gull in front of the Dawes Glacier