July 13, 2017

Humpback Whale Dives Deep in Strait of Juan de Fuca

Humpback whale fluke

[Erick D., M/V Sea Lion, 7/12/17, 1:30PM] Yesterday, Captain Mike, Sarah, and I took a full boat of eager folks out ot search for some whales. Sometimes the whales are a little bit harder to find than other days. Even though whales are massive creatures, even Humpbacks the bigger ones around here pale in comparison to the immense amount of water that they swim in. We headed south through San Juan Channel, out through Cattle Pass, and into the Strait of Juan de Fuca. The strait is one of the bigger bodies of water that surrounds the islands, the others are: Rosario Strait and Haro Strait. We started looking here because it is like being able to look at a huge field with multiple watering holes. The Strait might look like one big, flat piece of water but interspersed underneath, rocky and sandy, shallow areas have been left by the most recent glacier recession. As ocean water flows from the west in the Pacific to the Salish Sea the swells hit these shallow areas - called banks or reefs – and are forced upward bringing with them their nutrients and small planktonic organisms. Other, larger, organisms sense this and come to feed, which brings bigger and larger animals! So these banks and in between them is a good spot to search for large marine mammals because they gather at these spots also to find food. We checked first at Salmon Bank, which is the shallow bank that extends out from the southernmost tip of San Juan Island. We found some seals, a few porpoise, and a bunch of sea birds! Then we checked Hein Bank and Eastern Bank further south. We looked even further south and finally near the outflow of a river that has created a long sandy spit we spotted a Humpback Whale (Megaptera novaeangliae)! We first saw the blows from quite a distance since they shoot up into the air 15 – 20 feet sometimes and then eventually saw it fluke as it went on a deep dive. For its second surfacing we managed to get closer and we could see how big it was! Humpbacks in this area usually are around 40-50 feet long and weigh a tonnage corresponding to their length. We watched this whale a few more times as it surfaced near, fluked, and took deep feeding dives. We eventually headed back and even got to stop and see some adorable Harbor Seals lounging on some rocks before we made it back to Friday Harbor after another fun whale watch!


Naturalist Erick