NATURALIST NOTEBOOK 04 AUGUST TO 10 AUGUST

A typical, hazy, August day was how we began our week of whale watching on 4 August. We began one of our morning excursions on the southern edge of Stellwagen Bank. Stellwagen Bank is an underwater, plateau-like structure which is part of a National Marine Sanctuary. The Stellwagen Bank National Marine Sanctuary was designated by Congress in 1992, and the expanse of the sanctuary covers approximately 842 square miles. The southern edge of the sanctuary is only about six miles north of Race Point Lighthouse in Provincetown, and whale watchers traveling out of Provincetown are at a great advantage due to the close proximity of this important whale feeding ground.

Approximately one hour into the trip, we stopped on a pair of finbacks who appeared to be feeding. While humpback whales frequently make use of bubble clouds when they feed in order to scare and trap fish, finback feeding can be a little less obvious. While small bubble clouds are sometimes observed around feeding finback whales, they don’t tend to rise up through them the same way that humpbacks do. Instead, finbacks tend to roll on their sides and swim in circles when they feed. Today, the abundance of seabirds associated with the whales made it clear that there was bait in the area.

Later in the trip, this became even more obvious due to the presence of four adult humpback whales, including Seal, Division, and Gunslinger, were blowing bubble nets and using their tails to stun and trap fish.

Seal and Division

By the afternoon, the feeding had subsided; however, another species had moved into the area—the Atlantic white-sided dolphin! These dolphins, accompanied by several football-shaped calves, leaped and played among the humpbacks Onyx, and Seal, who were also in the area.

Onyx

August 5^th was another bright, clear, day, and Dolphin Fleet whale watching passengers experienced another day of intermittent feeding from our finback and humpback whales. Humpback and finback whales are capable of taking dives that last between 30 and 45 minutes if they need to, although this rarely happens in the feeding grounds, particularly when there is food near the surface.

Technically, whales don’t hold their breath, as people would do if they were submerged underwater. Whales are voluntary breathers, meaning that they have to consciously decide to take every breath. As such, sometimes whales that dive for a long time have to be expected, and such a thing happened on the morning trip to Stellwagen Bank. After having been approached by a humpback whale, we waited for it to resurface for quite along time before seeing its surface again, some distance away.

Luckily, we were able to find other humpbacks in the area, like Agassiz and Isthmus, who fluked, much to the delight of whale watching passengers, between their lunges through bubble clouds.

Agassiz

Isthmus

Although humpback whales generally feed whenever it is convenient, we will often observe them in transit, possibly on the mood searching for more patches of food. Today, we saw Dome traveling alone, fluking occasionally so that we had the opportunity

to observe the distinct, dome-shaped marking on her lower right fluke.

Dome

On August 6^thit was clear that Dome had been successful in her search during the previous day, as the evening’s trip located her among a large group of feeding humpbacks near the southwest corner of Stellwagen Bank. Dome was kickfeeding as other humpbacks including Entropy and Trident were lunging through bubble clouds, feasting on the thousands of small fish that had found themselves in the area.

Entropy

As it neared sunset, the captain declared that we would have to start heading back to Provincetown. No sooner had we began our journey southward when we came across another group of six humpbacks, feeding as voraciously as the first group!

Earlier trips had also been successful in locating more traveling humpback whales, such as Giraffe, a female born in 1987. Look at Giraffe’s right fluke and see if you can see how she got her name!

Giraffe

August 7^th was a calm, foggy day, but despite our limited visibility, we were able to see four different species of whale from both the mysticete and odontocete sub-orders, as well as two species of pinnipeds. Mysticetes are also known as “mustached whales”, which refers to the fact that they lack teeth in lieu of a bristly substance in their mouth known as baleen. This baleen helps large whales to feed on comparatively small, though energy-rich and abundant species of fish and crustaceans by functioning as a giant strainer. Because of the high concentration of these types prey items in the Gulf of Maine, baleen whales are the most commonly encountered animals on our whale watches.

On one of the morning trips, finbacks lunged through the water with such great speed that they created a wall of spray. As the feeding finbacks seemed to be heading East, we decided to head that way ourselves.

Lunging Finback Whale

Later in the afternoon, the feeding finbacks were joined by two other species of baleen whales, the humpbacks and the Minkes, all of whom appeared to be feeding as well. Among these whales, however, we also had a toothed species—the Atlantic white-sided dolphin! Characterized by the white and tan stripe on the side of their bodies, the large humpbacks and finbacks appeared all the more enormous among these smaller cetaceans, who don’t reach lengths greater than about eight feet. 20 to 40 dolphins leapt and milled about the feeding humpbacks and we considered ourselves lucky that we had found such a dense concentration of feeding animals. Though clear on land, the fog bank that had accrued over Stellwagen Bank left us with less than a quarter mile of visibility.

Cetaceans are not the only type of marine mammal making their homes in the waters surrounding Cape Cod. Today we saw the two types of seal most frequently found around the area during the summer—the gray seal and the harbor seal. Gray seals, with their long, horse-like faces and dark, sleek bodies, are often seen catching fish just off the beaches of the Cape Cod National Seashore!

Though August 8^th began as a rainy day, passengers on the Dolphin Fleet braved the moist weather, donned ponchos, and managed to have an excellent morning of whale watching. Among the whales spotted with great frequency that morning was a female humpback whale named Fulcrum. Sadly, the easiest way for us to identify Fulcrum is by the gruesome propeller scar that left her dorsal fin permanently damaged. Despite her injury, Fulcrum now appears to be healthy, and is back this summer with a calf!

Fulcrum

It is not often that we see too much association between humpback whale calves; however, this evening was an exception. On the sunset trip on the Dolphin VI we came across a group of six humpbacks—Anchor and her calf, Scratch and her calf, Springboard and Monarch.

Monarch

While the four adult whales took long dives, the two calves remained at the surface, swimming back and forth beneath the bowsprit of the Dolphin VI. They took turns spyhopping, rolling on their sides, and peering up at passengers! Anchor’s calf is so much smaller than Scratch’s calf that it was easy to tell them apart.

After several minutes had passed this way, the four adults burst to the surface with such exuberance that Anchor and Springboard nearly collided! By this time of year, it is not uncommon to see calves getting a little bit more adventuresome, not needing to spend every moment within a few feet of their mothers. This evening, it seemed as though these two humpback whale calves were learning more about social interactions while the adults concentrated on foraging for food.

Scratch’s Calf

While humpback calves are exciting to see, finback whale calves are arguably more so, as they are a more of a rarity in Stellwagen Bank during the summer. For finback whale aficionados, August 9^th was a particularly exciting day to be out on the water, as a finback whale mother and her calf were spotted on a number of occasions throughout the day.

Finback mother and calf

An even more unusual sight occurred on a midday trip when a finback was observed fluking, or raising its tail when it dove. We see this behavior frequently among humpbacks because it helps the whale to overcome their natural buoyancy on deeper dives. Finback whales, however, are negatively buoyant, and therefore don’t tend to fluke up.

Finally, on an evening trip, we stopped just off of Race Point beach to see a pair of finback whales that had been reported. These whales were so close to the beach that kayakers who had launched from the beach found themselves dwarfed by these enormous animals that have been known to reach lengths of over 80 feet!

A finback whale near Race Point

For humpback whale enthusiasts, the day was hardly a disappointment. A clear highlight was watching Trident, a female humpback first spotted in 1993, feeding on Stellwagen Bank. Trident brought a calf back to Stellwagen Bank last summer, and that calf was spotted today as well. Though no longer accompanied by its mother, this calf had learned well, and was also observed feeding on Stellwagen Bank!

Trident feeding

On August 10^th , much of our attention was focused on Scratch’s calf, who was breaching, lobtailing, and displaying many other active behaviors. Scratch was first identified in 1979 and this is her 8^th calf. A movement that is seen more frequently in calves than in adults almost appears like a headstand, where the calf emerges from the water tail first!

Scratch’s calf does a headstand

Scratch wasn’t the only calf spotted today. Entropy was observed traveling with Fern and her calf.

Entropy, Fern, and calf

By the mid-afternoon, we had located a large group of feeding humpbacks. Entropy, Fern, and her calf had joined up with Walrus, a large male first seen in 1982, as well as 6 other humpback whales, all of whom were blowing bubble clouds and feeding on large schools of fish.

Walrus

By the end of the day, the rain had stopped, and although the whales had spread out considerably, the sightings were plentiful. Three calves, including Isthmus’s calf, joined up and played near the surface. Meanwhile, nearby, Underline rolled on his side and slapped his flipper on the surface of the water, a behavior that can be spotted from miles away!

Underline

August is a great time to be out on the water, and the whales continue to teach us about the complex ecosystem in Stellwagan Bank.