October 7, 2015
The Mighty Fin Whale-October 5th, 2015
Today, like most days, the Salish Sea was demonstrating the full potential of this incredibly unique ecosystem. Captain Mike, myself, and the excited passengers aboard the Sea Lion were fortunate enough to bear witness to some incredible activity that is a sure sign that Autumn is upon us.
We headed South out of Friday Harbor after leaving the dock on a hot tip that there were some large marine mammals spotted South of Lopez island in the Strait of Juan de Fuca.
On our way down the San Juan Channel, we stopped to admire some harbor seals hauled out on a few exposed rocks. These small pinnipeds were anything but restful as they rolled around in the surf and splashed one another. Soon enough we took off and didn't stop until we encountered a few hefty Stellar's sea lions in Griffin Bay. There are some obvious differences between our Harbor Seals and these sea lions, first and foremost being size. While harbor seals max out around five or six feet long and around three hundred pounds, the largest Stellar's can reach twelve feet long and weigh closer to twenty-five HUNDRED pounds!
After admiring this enormous pinniped swimming upside down and rolling around in the quickly moving water we edged over to the shore to see a bald eagle before continuing South through Cattle Pass. Now was the time to start scanning for larger wildlife as we cruised toward McArthur Bank.
The Salish Sea is an incredibly dynamic environment with an immense ammount of divsersity, and we were about to see just how the open waters of the Strait of Juan de Fuca differed from the water closer to the San Juan Islands. With no land but the Olympic peninsula in sight, we were able to scan for blows.
As we cruised through the open water it wasn't just the blow that caught our eye, but a massive aggregation of seagulls, cormorants, murres, auklets, scoters and a myriad of other seabirds swirling above the water and diving below it. This phenomenon occurs over a large school of small fish under siege from a large marine predator as they are pushed toward the surface, known as a "baitball". Suddenly the marine predator made itself known: a pair of humpback whales!!
Most humpbacks are traveling at this point in the season from their high-latitude feeding grounds in Alaska to warmer climates to mate and give birth. However, there is no place like the Salish Sea to stop and fill their bellies. We watched these behemoths blow off-beat from one another so it appeared that there was just one but as they dived, first one then the other lifted its massive flukes into the air to go deeper.
Just to the east there was another, even bigger baitball occurring so we decided to see who the culprit was this time: As the whale surfaced we first saw a pair of immense blowholes exhale and then submerge, then a dark-grey back which went on for a long time followed by a dorsal fin with a very prominent sharp tip. This was no humpback, it was the elusive fin whale that had been hanging around our waters!!
The fin whale is the second largest whale in the world, reaching lengths of seventy feet or more. This particular one was probably a sub-adult, being no more than forty feet long. Seeing a fin whale in these waters is not only special because of their immense size, but also because it marks a potential return of their population.
It is thought that there was once a healthy fin whale population in this area before they, along with humpbacks and blue whales, felt the full force of the whaling fleets in the 17th and 18th centuries. The last recorded regularly seen fin whales in the Salish Sea were seen in the 1930's, making the appearance of our current finned friend a big deal. Hopefully this one juvenille fin whale marks the seed of a future population of the incredible creatures here in the Salish Sea.
We watched this immense creature, along with the two humpbacks, traveling between the largest baitballs that I have ever seen as the predators took advantage of the huge masses of baitfish: birds from above and whales from below. In the distance to the South we could see another huge swirling tornado of birds coupled with another humpback whale blowing.
One of the most incredible sights was to realize that the last herring of a particular baitball had been seized and as a result the thousands of birds could now relax. Gulls spread out on the water over about two square miles under the great looming presence of the outstandingly visible Mt. Baker to the Northeast. Another sign of the dissipation of the food was the steady movement of both the mighty fin whale and both humpbacks to the North towards yet another apparent baitball. Were the whales following the birds or the fish, the birds following the fish or the whales?
Either way watching this incredible demonstration of the ecosystem was to realize the importance (and misfortune) of the herring. They are hatched by the millions with what appears to be the sole purpose of being eaten, so they better reproduce while they can. Every animal that we are excited about seeing, from the common salmon (and everything that eats salmon) and harbor seals to the huge, elusive fin whales, depend directly or indirectly on these small fish. Seeing that all their predators are well fed indicates a vast herring stock. Here's to their health!
Unfortunately our time with the great whales was coming to an end, so we wished them well in their feeding efforts and began to head North back towards Friday Harbor. Along the way we were able to stop at the Whale Rocks to see more massive, snarling yet loveable Stellar's sea lions hauled out. We also encountered more seals, lots of common murre and even a harbor porpoise before we pulled into the dock.
Another Whale of a Day in the San Juan Islands!
Naturalist Mike J
M/V Sea Lion