Humpback Whales in Another Sanctuary

By Anne Smrcina

Two humpbacks feeding in Stellwagen Bank National Marine Sanctuary. Photo by SBNMS, NOAA Permit #775-1875

The marine mammals for which the Hawaiian Islands Humpback Whale National Marine Sanctuary was named have departed for their northern feeding grounds in the Pacific, but another national marine sanctuary is currently hosting these spectacular animals.

In the Atlantic waters of Stellwagen Bank National Marine Sanctuary, off the coast of Massachusetts, humpback whales are the stars of the summer wildlife watching season. In fact, several polls indicate the Stellwagen Bank area is considered one of the world’s premier whale watching destinations.

Bounty of the Bank

Early explorers and colonial settlers were astounded by the bounty of fishes and whales found in the waters of New England. Even today, the Stellwagen Bank is an important area for commercial and recreational fishing in addition to wildlife watching.

Located slightly more than 20 miles east of Boston, Stellwagen Bank National Marine Sanctuary sits between Cape Ann and Cape Cod at the mouth of Massachusetts Bay. The Cape Ann city of Gloucester, labeled America’s first fishing port, is a sanctuary gateway port and departure point for whale watching as is Provincetown on the outer tip of Cape Cod, a popular summer resort community. Whale watching trips also depart from Barnstable Harbor on Cape Cod, Plymouth, and Boston.

What Whale Watchers See at Stellwagen Bank

A whale-watching boat and feeding humpback are seen here at Stellwagen Bank National Marine Sanctuary. Photo by Ari Friedlaender, NOAA Permit #775-1875

While humpbacks at Stellwagen Bank demonstrate the breaches, flipper slaps, spyhops and other behaviors commonly seen in Hawaiian waters, the whales in their feeding grounds also engage in dramatic feeding behaviors. Humpbacks are famous for their bubble nets and bubble clouds, done singly or in cooperative groups. In a bubble net, the whale dives down in the water column and starts to blow a series of bubble streams around its prey of schooling fish. As the bubbles rise, they form a virtual wall of bubbles that corrals the school of fish. The whale, or group of whales, rise through the center of the bubble net with open mouths to capture masses of fish. Bubble clouds also serve to disturb and disorient the fish.

Seabirds seem to recognize that feeding whales bring prey to the surface. When whales burst through the waves, seabirds pick off fish seeking to escape the larger threat. The schools of forage fish also attract schools of small football-shaped bluefin tuna (the giant bluefins are solitary swimmers) and other commercially important fishes. Sometimes, prey and predators can make the surface appear to boil with all the active movements.

Research Explains Other Feeding Techniques

A whale tagging team and a humpback at Stellwagen Bank National Marine Sanctuary. Photo by SBNMS, NOAA Permit #14245

Bubble nets, however, are not the only hunting technique. Another style is bottom feeding. Here, the whale (again, working alone or in partnership with other whales) scrapes the seafloor to chase sand lance (small schooling fish) out of their hiding places in the sand. Although this activity is done at the seafloor and out of sight, scientists suspected the technique since whales showed raw patches on their jaws. Humpback research at Stellwagen Bank National Marine Sanctuary over the past 20 years has been providing data to explain these feeding styles.

With a multi-disciplinary, multi-institution team, sanctuary scientists affix small equipment packs to the backs of humpback whales with suction cups that cause no harm. The data recorders compile information on the depth, heading, pitch, roll and sounds (made and heard). The latest tags provide video from the underwater ride. After the tags detach, the research team retrieves them and downloads the data. Still images and visualizations (a form of animation) show just what the animal was doing, including the previously unseen bottom feeding.

Mothers, Calves at the Bank

Stellwagen Bank National Marine Sanctuary. Image courtesy of NOAA

Mother humpbacks and calves are a common sight in Hawai‘i, which is an important breeding/calving ground, but mothers and calves are also seen at Stellwagen Bank. In the North Atlantic, there are several distinct feeding grounds, of which the Gulf of Maine is one (the sanctuary is in the southwest corner of the gulf). Other feeding areas are off Canada, Greenland, and Iceland. After calves are born in the Caribbean Sea (the principal calving ground for the North Atlantic humpback population), mothers bring their young back to their respective feeding grounds. Stellwagen Bank appears to be an important nursery area in the Gulf of Maine. After their prolonged fast over the breeding season and long migration, mother whales gorge on large numbers of forage fish while weaning their calves and teaching them how to hunt.

Whale watchers often see mother-calf pairs, sometimes accompanied by an escort whale. While the adults actively feed, the young whale can follow their example, but at times will engage in what appears to be play behavior, breaching or investigating the vessel.

Not Just Humpback Whales

TrackPlot whale tracks from tag data. Image courtesy of SBNMS/UNH.

Although whale watching tours favor humpback whales, other species provide satisfying viewing. Lucky passengers can sometimes view pods of Atlantic white-sided dolphins or common dolphins escorting whale watching vessels and riding their bow wakes. The second largest animal on the planet – the fin whale – is another regular visitor to the sanctuary. The long, lean whale, reaching up to 75 to 80 feet, is referred to as the greyhound of the sea. Its dives are generally quite subtle as it does not raise its tail when it dives, but the whale can engage in explosive feeding lunges when prey is at the surface. Another whale watching subject is the minke whale, the smallest of the great whales, and also the whale still hunted in parts of the world. It is identified by the white patches on each of its flippers.

Working to Protect Whales

The Hawaiian Island Humpback Whale National Marine Sanctuary and Stellwagen Bank National Marine Sanctuary have much in common, including the fact that both sites were designated in the 1992 reauthorization of the National Marine Sanctuaries Act. Staff members from both sanctuaries work to better protect our living resources through research, education, and conservation efforts. Follow wildlife watching guideline (https://sanctuaries.noaa.gov/wildlife-viewing/) if visiting the sanctuaries.

Visit https://stellwagen.noaa.gov to learn more about Stellwagen Bank National Marine Sanctuary.

Visit https://sanctuaries.noaa.gov/earthisblue/wk296-sbnms-whale-watching.html to view a short video about whale watching at Stellwagen Bank National Marine Sanctuary.

Anne Smrcina is the Education and Outreach Coordinator at Stellwagen Bank National Marine Sanctuary. Based at their headquarters in Scituate, Massachusetts, she is responsible for preparing news releases, general information publications, exhibits, social media, and educational materials for informal and formal educators and the general public. She was a recipient of the National Marine Sanctuaries’ Sea to Shining Sea Award for her work with an annual marine art contest. Anne can be reached at Anne.Smrcina@noaa.gov