On Saturday, June 5, we returned to southeastern Stellwagen Bank, where humpbacks have been spotted in droves throughout late May. Named for Navy Lieutenant Henry Stellwagen who surveyed and mapped the area in 1854, Stellwagen Bank is approximately 18 miles long. The boundaries of the Stellwagen Bank National Marine Sanctuary enclose an area of 842 square miles, and include Stellwagen Bank, as well as Tillies Bank and a portion of Jeffrey’s Ledge in its northernmost region. Leaving from Provincetown Harbor, it takes us less than an hour to reach the southernmost region of the national marine sanctuary, making Provincetown one of the closest ports to major whale watching areas.
Heading eastward, we encountered a larger group of humpback whales, including Cajun and her calf, Perseid and her calf, and Milkweed. We suspected that the adults were feeding at the bottom, as they surfaced infrequently, with abrasions on their lowers jaws suggestive of foraging in the gravelly and sandy bottom. Luckily, while the adults were feeding below, the calves stayed at the surface, and by the end of the trip, began to breach!
We don’t know why humpback whales breach, or jump out of the water, but in the case of the 3-5 month old calves, we suspect that it might be a playful behavior. It also might be a way of getting mom’s attention. Maybe these little whales are hungry too!
When this curious humpback was through checking us out, we trucked eastward towards a very small spout. As we got closer, we realized that it was a very small humpback. As it was only about 10 feet long, it could only be a calf. But where was its mother? We watched the calf for a few minutes until a larger whale surfaced. Here was mom! It was Perseid, one of the whales from the day before.
In true humpback fashion, the group that we had been watching the day before did not remain together, but instead, broke up and reformed with new members. Perseid and her calf had ventured off on their own, and nearby, Cajun and her calf were joined by Freefall and Jabiru, who have been seen very often with this group in the past few days.
By June 7, the same humpbacks had moved westward, toward the southern edge of Stellwagen Bank, and more humpbacks had arrived. We were particularly excited to see Nile, a female born in 1987. Nile is one of our favorite humpbacks, easily recognizable by her hook-shaped dorsal fin and the Nile River-shaped pigmentation pattern on her tail. She has given birth to several calves in her lifetime, most recently in 2009. Because she gave birth last year, we would not expect her to be with a calf now, as a typical calving interval for humpbacks is every 2 years. It is, however, entirely possible that she is pregnant, although we have no way of knowing. Humpback whales mate in the Caribbean during the winter, travel to North Atlantic feeding grounds in the summer, and return to the Caribbean the following year to give birth. Next year, we will watch to see if the 2009 humpback moms return with calves!
June 8th was an exciting day east of Stellwagen Bank when three species of cetaceans were spotted. Cetacean is the scientific classification for marine mammals which have their nostrils or blowholes on the dorsal sides of their heads. All dolphins, porpoises and whales fall into this order. The mid-day trip aboard the Portuguese Princess II began as Charger, a humpback first seen in 2007, approached and investigated the boat, swimming around us for almost 25 minutes! Once we were finally in a position to safely leave Charger behind and do further exploring, we quickly spotted a Minke whale. These small baleen whales are fast and rather elusive, so we were not surprised when we did not spot it again. After spending some time watching a humpback named Elephant, also first seen in 2007, we started to notice a group of small dorsal fins at the surface, rapidly approaching our boat. We soon had a small pod of Atlantic white-sided dolphins crossing our bow!
Later in the day, the winds decreased and we could see a whale in the distance starting to kick its tail, creating a huge plume of white water. Hoping to see some feeding, we steamed northward! Upon arriving, we noticed large schools of sand lance swimming near the surface, and a large humpback, who could not be immediately identified, kicking and blowing bubbles. Humpback whales use these behavior to startle, corral and trap fish before lunging through the school with an open mouth. Although this whale never emerged with an open mouth, we assumed that it was probably feeding somewhere below the surface. Soon, other whales were moving into the area, most notably, a large female named Scylla. Like the first humpback, Scylla created a wall of bubbles, with was closely followed by an open mouth lunge at the surface. At times, we could even see the small fish jumping out of her mouth attempting to escape! As it became time to leave, we could see that other humpbacks were headed towards the area, probably with the intention of feeding. We wrote down the coordinates so we could return to the same area the following day.