August 24, 2017

Tiny Humpback Hangs Out in the San Juans

[Naturalist Sarah C. 8/24/17 M/V Sea Lion 1:30 Departure]

An itty bitty humpback has been spotted perusing the waters south of Lopez Island for three days in a row now. This little whale nubbin obviously favors his chosen location, and it's an unusual one for massive baleen whales like him to be spotted in, much less observed feeding in for days on end.

Adult humpbacks are generally 40 to 50 feet long, the same lenght as a school bus! Juveniles like this just-over-one-year-old whale are maybe 35 feet long, which is still pretty sizeable, and sports nearly 35 tons of body weight. When they're first born, humpback whale calves are 15 feet long and lacking a substantial layer of blubber to keep them warm. Luckily (well, more like intentionally), birthing season occurs in the warm waters of the South Pacific, making for excellent conditions to bring a new humpback into the world. Calves nurse from their moms for the first year of their life, ingesting enough 80% milk fat milk to gain almost 100 pounds on the daily. It's no wonder then that our whale today had grown to a whopping 35 feet in one short year!

The south end of Lopez is fairly unique in the San Juans, since it has a shallow shoreline before dropping off to 400+ foot deep water. This variation in ocean floor depth causes a substantial amount of upwelling (deep, nutrient rich water being forced upwards by underwater cliffs, where it's exposed to sunlight). Upwelling creates for huge phytoplankon blooms, which support the krill and small, schooling fish that our juvenile humpback is feeding on daily. Adult humpback whales generally feed near the underwater banks in the middle of the Strait of Juan de Fuca, a wide and spansive body of water connecting directly to the Pacific Ocean. Perhaps when this whale grows more, he'll be a little less keen on the narrow bay that he seems so fond of today!

His feeding patterns did make for a pretty interesting whale watch, though. We got to observe lots of fluke-out dives, where this tiny whale got to show off his beautiful black-and-white patterned fluke, unique to only him. We also got up-close-and-personal with him when he unexpectedly swam right under out boat, popping up on our left hand side with a powerful exhalation.

We also had the chance to check out some Steller's sea lions, harbor seals, and a bald eagle nest, as well as circumnavigate the entirety of Lopez Island today before heading back to Friday Harbor. All in all, it was a fabulous day on the water!