NATURALIST NOTEBOOK 19 MAY TO 25 MAY

This week we went from winter weather to warm summertime breezes. Saturday May 19^th brought rain and Northeast winds. It seemed as if we would have to cancel another day of whalewatching. But by afternoon, the winds lessened as did the seas and although choppy offshore, we made our way to Stellwagen Bank. Despite foggy conditions we found Loon and her fifth calf on the southwest corner of the Bank. A small humpback named Buzzard and a few fast moving finback whales were sighted as well. By the evening, the fog lifted and our visibility greatly improved. We made our way to the area where the whales were spotted a few hours before- but there were no whales in sight! Eventually we moved a few miles east to the edge of the Bank and sighted Loon and her calf, our first, fourth generation humpback Eden and a large female named Trident. The whales were on the move and not staying in one place for long. That is with the exception of Loon’s calf who repeatedly swam around the Dolphin 8 as we drifted.

Rapier Kickfeeds Near Stellwagen Bank

Sunday morning was calm with patches of fog. We left the dock early and traveled to the edge of Stellwagen Bank and eventually the southwest corner. There were spouts everywhere we looked. Most of the whales we spotted were humpbacks and almost all were feeding. The two finback whales in the area lunged across the water’s surface. Birds gathered over the bubble clouds and nets blown by the humpback whales as the whales surfaced- mouths open- engulfing thousands of gallons of food and water to strain through their baleen plates. It was an amazing sight. We drifted and dropped our hydrophones into the water. This underwater microphone picks up whale sounds associated with feeding- a series of woops, moans and grunts broadcasts over the PA system. Rapier and her 2006 calf, along with Nimbus, Anvil, Falcon, Buzzard and Liner were actively feeding. We later sighted Measles, Giraffe and Vulture feeding on the small fish that rippled the water’s surface. By the afternoon the fog lifted and rain set in. The whales, a bit more scattered, traveling more and feeding less, still were on the Bank in great numbers.

Liner’s Distinctive Fluke

21 May brought us to a number of humpback whales on the Southwest corner of Stellwagen Bank, including Fern and her calf, who appeared to be nursing. For the first few months of a humpback whale’s life, the whale will feed on its mother’s rich milk, which is about the consistency of cottage cheese. This is an important source of energy and nutritional content for the young whale who, in the first few months of its life, has journeyed thousands of miles from its birthplace in the Caribbean to the cooler, more productive waters of the North Atlantic.

Fern’s 2007 Calf

Calves do not suckle. Instead, the calf will approach the mother’s mammary slit as the mother humpback squirts the milk toward the calf’s mouth. Observers from a boat platform can infer when a calf is nursing when the calf is seen surfacing on alternate sides of the mother’s body as it presumably passes under mom to take in gulps of food.

By 22 May, Many of our humpbacks and finbacks had trucked north to the BE Buoy, located in the center of Stellwagen Bank National Marine Sanctuary. The BE Buoy marks a point along the Boston shipping lane, which runs through the center of the sanctuary. The presence of the buoy reminds us that Stellwagen Bank is, in fact, a multi-use sanctuary, designated as such by Congress in 1992. This means that on any given day, one might find any combination recreational boaters, merchant vessels, fisherman, and scientists within the boundaries of the protected area.

The National Marine Sanctuary program faces a conundrum in the face of human-induced threats, such as ship strikes, entanglements, and pollution, because the goal of the program is to protect the sanctuary’s resources while promoting a multiple-use philosophy. Watching humpbacks feed within a hundred yards of the buoy, a merchant ship’s silhouette looming on the horizon and fishing gear dotting the seascape, we were reminded of the fact that although we experience very different existences than our marine counterparts, we need to find ways to share our common environment.

On 23 May we were excited to get another glance at the finback whale mother/calf pair that we’ve been watching for the past few weeks. Like humpbacks, finback whales will frequent Stellwagen Bank’s productive waters to replenish their blubber stores after the huge energetic expense of giving birth to and nursing their calves. Because we know so little about the migration patterns of finback whales, it is always exciting to see a finback mother/calf pair. This particular finback is particularly recognizable because of her enormous dorsal fin, which appears to be over two feet tall.

After marveling at the sheer size of these creatures (the calf itself is at least 20 feet long!), we noticed whitewater on the horizon. Looking through the binoculars, we observed the unmistakable splash of a humpback whale leaping out of the water—a breach! As we approached, the whale, who we soon identified as Tongs, stopped breaching, but continued to lobtail. With no other whales visible in the immediate vicinity, we wondered whether the whale was using the sound of its body contacting the surface of the water to communicate with whales in the distance.

Bubble Cloud Near Bow

24 May’s trip took us back to the Southwest corner of Stellwagen Bank—a frequent hotspot for humpback feeding. Observant whale watch passengers sometimes observe that whales sometimes seem to feed along an obvious line in the water. Frequently, these lines, or “rips” denote the presence of an upwelling. Upwellings occur when ocean currents flowing in a counterclockwise motion in the Gulf of Maine encounter the vertical edge of the bank and push nutrient-rich water from greater depths to the shallower regions of the bank’s surface. Here, phytoplankton can take advantage of the increased sunlight and photosynthesize, expanding their biomass. As a result, the zooplankton population is nourished by the increase in phytoplankton, and the zooplankton nourishes the fish populations which feed our whales.

Bubble Net Off the Bow

Barb, a 20 year old male humpback, named for the Barb-shaped marking on his triangular dorsal fin, was one such whale observed feeding along one of these rips. Barb, along with three other humpbacks spent much of the afternoon cooperatively blowing bubble nets to trap fish, finally swallowing gallons of them whole.

Similar conditions on May 25 brought us to feeding humpback whales on the southern edge of Stellwagen Bank again. As humpbacks blew clouds of bubbles right off the bow of the Dolphin VIII, it was possible to see the pleats on the underside of their bodies expand and contract as they engulfed food and pushed out seawater between their hundreds of baleen plates.

Feeding Humpback Surrounded by Birds

By the afternoon, their behavior had changed dramatically. Instead of the furious feeding frenzy seen earlier, the very same humpbacks were observed in their resting state called “logging”. Because whales are voluntary breathers and need to consciously decide when to take each and every breath, they don’t exhibit the same sleeping habits that other mammals do. Humpback whales are buoyant enough that they can suspend themselves near the surface of the water without moving, which allows them to periodically breathe as they rest. The log-like appearance of the whales as they engage in this behavior is evident to anyone who has ever observed them in this state.

Satiated from their morning feeding and their noontime snooze, we had a remarkable afternoon which included three separate “close boat approach” instances. A highlight of the afternoon included a sighting of Perseid and her calf. Perseid’s calf is the great grandcalf of Compass, who is still returning to these waters. Perseid’s calf represents the second instance a fourth generation of known humpback individuals.

Our sendoff for the day included another approach from two humpbacks, thought to be juveniles. They passed back and forth underneath the boat, periodically lifting their heads directly out of the water to get a better look. A spyhop! Finally, as we left these whales to head back to Provincetown, they lifted their huge pectoral flippers out of the water in what many passengers interpreted as a farewell gesture.

The glassy calm seas and the remarkably close look at some of the world’s most beautiful and mysterious creatures marked the end of another successful week of whale watching on the Dolphin Fleet.