Yesterday we left the dock with reports of humpback whales just south of San Juan Island, a short jog from Friday Harbor. On our way there, we happened upon dozens of harbor seals just off of Cattle Point and paused to watch them fishing for the small fish being carried in by the quick flood.
We then carried on for a few more miles until we reached the location that the humpbacks had been spotted in last. Baleen whales especially love feeding in the waters between San Juan Island and the Olympic Peninsula because they contain a scattering of underwater banks. These banks, resembling underwater mesas, vary the water depth from 600 feet to a mere 40 feet. This sudden depth change causes deep, nutrient rich water on the bottom of the ocean to be forced upwards by the walls of the bank.
Colder water is better at storing oxygen and other nutrients, so when it reaches the surface and gets exposed to sunlight it harbors a perfect environment for phytoplankton blooms. Phytoplankton are the food source for the entire marine ecosystem, feeding krill, which feed small schooling fish, which feed larger animals such as seals, sea lions, and baleen whales. For this reason, massive filter feeders like humpback whales thrive in the waters just south of San Juan Island.
We observed a pair of adult humpbacks peruse the area, likely feeding on the fish and krill below the surface. We got some amazing looks at these individuals before heading back to shore and were infinitely grateful to have such magnificent animals just a short ride from the marina.