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On September 20 we revisited what has become our regular group of humpbacks. Whisk and Canopy and their calves were once again joined by Pele, a male humpback of unknown age. Humpback whales will remain with their calves for approximately one year after their births, which usually occur in the early part of the year. At this time of year, as they prepare to leave their mothers in a few months, the calves are showing signs of independence. Today, straying at least 400 yards from its mother, Whisk’s calf displayed active surface behavior, rolling and tail breaching. These bouts of independence are often short-lived, as calves are still depending on their mothers for food, and Whisk’s calf soon rejoined its mom.
Canopy and Whisk’s calves at play
Meanwhile, Canopy and her calf were less active, floating near the group several boat lengths away. With their thick layer of blubber, humpbacks are very buoyant animals, and can use this to their advantage when they need to rest. When we see them inert at the surface, we call this rest behavior “logging”, as they look like big logs to some observers.
September 21st was another bright clear day with a light, warm breeze blowing in from the southwest. Ideal conditions for whale watching took us back to the southeast of Stellwagen Bank where we again stumbled upon Pele, Whisk, Canopy, and their calves. Today, they were joined by a whale named Lupine, a humpback with an almost all black tail or fluke.
Also notable today were the 10 to 12 Minke whales that continually surfaced around the Dolphin VIII as we watched these humpbacks. Like the humpbacks, Minke whales are baleen whales, meaning that instead of teeth, they use the flat, bristly plates in their mouths like filters when they feed. Baleen whales, or mysticetes, on average tend to be larger than their toothed cousins. However, Minke whales, as the second smallest mysticete, rarely exceed lengths of 25 feet. Most of the Minke whales in the Gulf of Maine are thought to be juveniles, so the Minkes that we see on our vessels are quite small and also quite elusive. However, as there were so many in the area, passengers got a chance to compare the small, sleek, quick Minkes to their more robust relatives, the humpbacks.
By September 22, our group of humpbacks stayed together, save for Lupine, who was replaced by Milkweed, a young humpback born in 2000 to a whale named Zeppelin, also seen this year. By September 23rd, this group structure still hadn’t changed, although these animals were notably more active on this bright, windy day. As the Dolphin VIII approached this group, the crowd gasped as several of these humpbacks rose up, perpendicular to the water’s surface in a behavior called a “spy-hop”. The naturalist noted that this was one of very few times she had ever seen so many adult humpbacks engaging in a true spy-hop, where the whales’ eyes actually broke the surface.
Meanwhile, Aerospace, thought to be a juvenile, appeared to be as interested in this group as we were. Aerospace approached the group and appeared to be in sync with them for the remainder of our time with them that morning, but by the time we returned to the group in the afternoon, Aerospace was nowhere to be seen!
On several occasions this week, including September 24th, we got a chance to see a non-cetacean species of interest: the Mola mola. The Mola mola, one of three species of ocean sunfish, can sometimes be seen basking on its side, catching our eye with its flip-flopping fin. These animals are sometimes considered to be the largest type of zooplankton. Zooplankton refers to any animal that is suspended in the water column and that drifts with the current. Though they can weigh several hundred pounds, the bizarre-looking Mola fits that description, although it is certainly a contrast to the zooplankton that we usually picture when we consider the plankton that feeds our North Atlantic right whale and our basking sharks.
September 25th brought us back to our supergroup of six humpbacks. Milkweed and Pele escorted Canopy, Whisk, and their calves. As the calves rolled at the surface, they raised their long, white flippers and proceeded to smack the water with them. This behavior is thought to have some role in group formation and dissipation, but as these young animals are learning the ways of adult humpbacks, it is possible that these calves were just playing.
After leaving this group, we happened upon another Orbit and her calf, accompanied by third humpback named Wyoming. Although humpback whale cow/calf pairs don’t always travel with an “escort”, it is not an uncommon sight, as male whales that accompany cow/calf pairs tend to have better reproductive success. However, they don’t always spend extended periods of time with the pairs, which is why we have been so surprised to see the Canopy and Whisk group stay together for so long.
Although windy weather kept us in port for the weekend, stay tuned for updates from the following week!