“We had an absolutely magical whale sighting over the weekend!” said the caption of a Sept. 11 Facebook video from Alaska Sea Adventures, a yacht expedition company.
According to the post, this whale wasn’t one of the humpbacks that is commonly sighted in the area.
“After a closer look, we realized we were observing a fin whale feeding on krill!” said the post. “Fin whales are the second largest species of whale and are incredibly rare in the Inside Passage of Southeast Alaska.”
Only blue whales are larger than fin whales, per the National Oceanic and Atmospheric Administration Fisheries. Sometimes the two species mate with one another.
While fin whales – distinguished by the fins on their backs – are found throughout the world’s oceans, commercial whaling depleted their populations. Today, they are listed as endangered through the U.S. Endangered Species Act.
“Fin whales have sleek, streamlined bodies with V-shaped heads,” said the NOAA Fisheries. “They have a tall, hooked dorsal fin, about two-thirds of the way back on the body, that rises at a shallow angle from the back,” as well as distinctive coloration ranging from black to brownish-gray on the sides and white on the underside.
These typically live to be around 90 years old They grow to be 75 to 80 feet long weigh around 40 to 80 tons with a diet consisting of about two tons of food daily.
“During the summer, fin whales feed on krill, small schooling fish (including herring, capelin, and sand lance), and squid by lunging into schools of prey with their mouth open, using their 50 to 100 accordion-like throat pleats to gulp large amounts of food and water,” said the NOAA Fisheries. “They then filter the food particles from the water, using the 260 to 480 baleen plates (long, flat plates made of fingernail-like material called keratin) that they have in place of teeth on each side of the mouth. Fin whales fast in the winter while they migrate to warmer waters.”
Fin whales are typically found in the deep, so a sighting near the shore was a rare experience for the Alaska Sea Adventures crew.