On July 7, our travels took us east of Stellwagen Bank to an area known as “The Triangle.” In this particular area, upwellings can occur as currents collide with the steep, sloping drop-off from Cape Cod or with the eastern edge of Stellwagen Bank. In the morning, many of the humpbacks in the area, including Entropy and Ampersand, seemed to be traveling to that area in search of food. Passengers also noticed much splashing and white-water in the area, and upon closer inspection, discovered that they were watching bluefin tuna thrash and jump. Because of their size and body shape, tuna are often mistaken for dolphins from a distance!
In additions to the many humpback whales and finbacks we saw that day, passengers on the Dolphin VI during the afternoon trip were treated to spectacular looks at a basking shark!
Basking sharks, like baleen whales, are filter feeders, meaning that they have a straining mechanism in their mouth which they use to separate prey items from seawater. Basking sharks, like the North Atlantic right whale, sand lance, and the Wilson’s storm petrel, are feeding predominantly on copepods, shrimp-like crustaceans that are very high in lipids, but that are no larger than a grain of rice. The fact that such diverse species all travel to Stellwagen Bank to feed on these tiny crustaceans are a testament to how crucial this species of zooplankton is to the health and diversity of Stellwagen Bank.
We returned to this area the following day, on July 8, and came across a more unusual species, the Sei whale. Humpbacks, finbacks and Minkes tend to be the more typical sightings on summer excursions to Stellwagen Bank, so spotting another species of baleen whale was very exciting for naturalists and passengers alike!
Sei whales can reach lengths of almost 50 feet, and are comparable in shape to the sleek, fast, finback. However, their distinct, broad dorsal fin, and rapid surfacing pattern makes them distinguishable from their larger relatives. Like the finback, their migration patterns are poorly understood, though likely related to food availability. Sei whales, however, seem to have a more variable and less-predictable migration pattern. They tend to travel alone or in small groups, and sure enough, this was the case today! Two groups of approximately 5 animals were observed, surfacing and diving synchronously.
On July 9, passengers on the Dolphin VIII got a chance to see two different species of mother and calf pairs, the most exciting of which was a finback mother and her calf. Because we’ve learned so much about humpback whales by identifying individuals and following their behaviors in the Gulf of Maine, several Dolphin Fleet scientists are trying to spearhead an effort to do the same with finback whales. Because finback whales are so fast and elusive, they can be a little bit more challenging to study, but today we were excited to see a repeat finback visitor to the Stellwagen Bank, a female named Goatdance. Goatdance gained notoriety last season when she was photographed fluking, a behavior rarely seen in finback whales. This year, she returned to the area with a calf.
In addition to this finback mother and calf pair, we also saw a number of humpback mother and calves, including Seal, Reaper, and Perseid, all accompanied by their calves, all of whom are about six months old. Over 40 humpback whale calves have been documented this summer in the Gulf of Maine!
July 10 began as a very foggy morning. Despite less than a mile of visibility, we happened across a finback whale. Finbacks are notorious for being difficult to watch, and to find this whale in the thick fog, it became necessary to listen for its loud exhalation. Once we relocated the whale, we noticed that it was swimming in a wide circle, which meant that it was probably feeding. Sure enough, the next time the whale surfaced, we noticed that the underside of its body was bulging, expanded, and probably filled with sand lance, the predominant food source for finbacks in the area. The finback whale’s mouth takes up approximately 1/5 of its body, and with a body length of up to 90 feet, the finback can engulf an enormous amount of fish with every mouthful.
By the afternoon, the fog had cleared considerably and we were able to motor to a spot where a group of over 10 humpbacks, including Entropy, Cajun, and Buzzard, had congregated. We noticed bubble clouds, which appear as green foam rising to the surface. Humpbacks often blow bubble clouds to scare, confuse, and ultimately trap fish. Normally, the whales will lunge through bubble clouds soon after creating them; however, these whales seemed to blow bubble clouds and then abandon them. Had the fish left the area or were the whales feeding subsurface? Our suspicions of the former were confirmed as the whales, almost simultaneously, began traveling in a straight line toward the east, in search of a new patch of food.
On July 11, the fog returned and our visibility wavered between ¼ and 2 miles. Despite limited visibility, we were able to find Banyon, who was actively lobtailing, tail breaching, and even lying on its side, slapping its flippers! By the afternoon, the fog cleared and we returned to an area southeast of Stellwagen Bank where a feeding frenzy had begun. Humpbacks, including Fracture, Cygnus, and Coral, emerged from the depths with their mouths wide open. Seabirds, including gulls and shearwaters flocked to the area and some even tried to snatch leftover fish from the whales’ mouths! Humpbacks and finbacks lunged through schools of sand lance with such force that it looked as though they were going to have a head-on collision. Despite the similar ecological niches, and food choices, however, these species don’t display aggressive territoriality when it comes to their feeding grounds.
By the evening’s trip, the feeding had subsided, but the sightings were no less numerous or exciting. A clear highlight was a group of 4 humpback whales, Calderas, Eden, Anchor and her calf, joined by a small pod of 20-30 Atlantic white-sided dolphins! As Anchor’s calf rolled on its side, these dolphins leapt and swam rapidly among the four, larger whales.
This was a great opportunity for whale watch passengers to note the difference between odontocetes, which are toothed whales, and the category under which dolphins are classified, and baleen whales, which include humpbacks. One notable difference is the social structure, evident during this interaction. Toothed whales, in general, tend to travel in social groups, or pods. These are long term social structures. By contrast, humpback groups tend to be small and unstable. Sure enough, when Anchor and her calf were sighted later in the week, Eden and Calderas were not in their presence.
On July 12 the fog had lifted for good and we enjoyed almost unlimited visibility and sunny skies. Fracture, Ampersand, and Colt were traveling together. Colt is a humpback whale famous for his curious approaches of whale watch vessels, but today, he seemed more interested in food than the boats in the area.
Ampersand and Fracture
Stellwagen Bank is one of five different feeding grounds in the North Atlantic, and humpbacks tend to return to the same feeding ground year after year. Because of this trend, we tend to see old and new whales within close proximity of one another. Some of these new whales are juveniles, and have not yet received an official name. One such whale that has been showing up repeatedly, and who is probably a juvenile, has particularly distinctive features, including a white spot by either eye.
Unknown humpback with white eye spots
We also saw some of our old favorites, including Salt and Cardhu, both of whom are females who gave birth to calves last year. Salt was the first humpback to get a name in the Gulf of Maine, and we’ve been watching her since 1975. Salt and Cardhu are often seen in close proximity to one another, and today they were busy feeding. Female whales are slightly larger than males, and Salt and Cardhu were noticeably larger than the unidentified juvenile we had watched earlier.
Salt and Cardhu surface feeding
The morning of June 13th was clear and calm and there was no shortage of whales in the area. Reaper and her calf were part of a large aggregation of feeding humpbacks. Humpback whale calves are born in the early part of the year, and do not stop feeding on their mothers milk until they are six to eight months old. Meanwhile, their mothers, having given birth to one-ton creatures, have special need to bulk up during the summer. As Reaper fed on fish near the water’s surface, her calf played nearby, rolling around on its back and breaching.
Later in the evening as the wind picked up, our humpbacks became more active and breaches were everywhere! Because we see quite a bit of breaching, or jumping, in rougher sees, some scientists think that breaching might be a way for humpbacks to facilitate movement or breathing in rough weather. Another idea occurred to us as we watched Anchor and her calf. Anchor’s calf is noticeably tiny, and we were surprised to see it venture so far away from its mother. As it breached repeatedly, we wondered whether it was trying to signal its mother. Supporting our suspicions, Anchor breached, which seemed to cause the calf to head in her direction. It was a happy ending to the last whale watch of the week when we watched Anchor and her calf reunite, and swim away!
Anchor and calf