Humpback Whale
(Megaptera novaeangliae)

Federally Endangered

Description

Humpbacks are the best known whales, yet are seriously endangered. Their relatively slow swimming speed and acrobatics make them the favorite of New England whale watchers. Humpbacks are large, black whales that readily show their tail flukes when diving. They have wart-like bumps around their heads and in front of their twin blowholes. The spout is about 10 feet high and is more squat than that of the finback. The dorsal fin is located far back on the top of the body and is smaller than that of finback or sei whales. Baleen plates are rooted in the gums of the upper jaw and number between 270-400 on each side of the mouth. On the underside are 14-35 parallel grooves that extend from the throat to the navel or beyond. Barnacles are usually located on the chin, anterior portion of the grooves, back edges of the flippers, and flukes. Coloration is typically black above and white below. Humpbacks have long, narrow flippers (¼ to 1/3 of total body length) with knobs on the anterior margins. Flippers are usually white above and below, but the upper surface may be spotted with black or all black. Tail flukes are all black with white spots along the trailing edges and undersides. Individual whales can be identified by the unique color patterns on their flukes. Females are larger than males and measure 45-50 feet, while males measure 40-48 feet. Adults weigh 25-40 tons. Map of range and known locations of humpback whale

Range and Habitat

Humpbacks are found in all the world's oceans, but are uncommon in arctic regions. They migrate to feeding areas in northern latitudes in the summer and return to warmer tropical Caribbean waters to winter and breed. In the North Atlantic, there are populations in the Gulf of Maine, Nova Scotia, Newfoundland, Labrador, and Greenland. In these areas, humpbacks inhabit waters over the continental shelf. The humpback whale is relatively common in the Gulf of Maine and is observed frequently by whale watchers.

Life History and Ecology

On their northward migration, humpbacks pass through New England waters in April and May. Some animals remain in the Gulf of Maine for the summer, where they feed primarily on herring, sand lance, and other small fish. Other humpbacks continue northward, reach Labrador by July, and remain there until September. On their southward migration, they pass through New England waters from October through December.

Humpback whales are seen singly, in pairs, or in small groups of 12 or more. Just before a deep dive, they expose a greater portion of their backs, curve their bodies, and display their tail flukes perpendicular to the water surface. They are among the most acrobatic of whales and often are seen breaching (leaping out of the water), lobtailing (standing on their head and slapping their tail on the water), waving their flippers in the air, and splashing their flippers on the water. Vocalizations include loud whistles and wheezing sounds, which may be used for communication. During the breeding season, males may produce complex "songs." Humpback whales swim along with their mouths open and use their baleen plates to filter small shrimplike crustaceans (krill), schooling fishes, and squid from the water column.

Humpbacks reach sexual maturity at about nine years, when males reach 33 feet long and females about 36 feet. Breeding may occur throughout the year. In the Atlantic, the shallow waters of the Caribbean Sea provide wintering and breeding areas. Calving occurs at two-year intervals, but some females have a calf every year. The gestation period lasts 11-12 months. The single calf is weaned at 5-6 months of age or when it reaches about 25 feet in length. Humpbacks may live to be about 50 years old.

Threats

Humpback whales were easy targets for whalers because they inhabit waters close to shore and are slow swimmers. Entrapment and entanglement in fishing gear occurs frequently in the Gulf of Maine, where 4-6 entanglements are documented annually. Studies show that 48-78 percent of animals in our region have scars from entanglement. Ship strikes, disturbance from underwater acoustics, commercial whale watching and research boats, and habitat degradation are additional threats. Commercial fishing may compete with whales for some species (herring), or remove predators like mackerel, which may result in increases in sand lance, a preferred food.

Conservation and Management

Humpbacks are among the most endangered of the large whales. Between 1905-1965, 28,000 humpbacks were killed. In the North Atlantic, they were protected from commercial hunting in 1955. Populations are now believed to be slowly increasing; however, only about 8,000 individuals remain in the western North Atlantic. It is believed humpbacks number 15,000-20,000 worldwide at present, or about 15-20 percent of the original population. Human-caused injuries and mortalities are believed to be frequent enough to be limiting the rate of recovery.

In 1965, humpback whales were protected worldwide by the International Whaling Commission, and they are now protected by the federal Endangered Species Act and Marine Mammal Protection Act. The Maine Department of Marine Resources has lead management authority for marine mammals, including the humpback whale.

Recommendations:

The Maine Department of Marine Resources recommends that National Marine Fisheries Service Guidelines for whale protection be employed. Regulations can be found at : www.nero.nmfs.gov/whaletrp/. Current (2002) guidelines include the following:

Dedicate state education and outreach efforts to fishermen.
Close critical whale habitats to some types of fishing gear during times when whales are likely to be present.
Prohibit some fishing practices (e.g., leaving inactive gear for more than 30 days) that increase risk of entanglement.
Require some gear modifications in federal waters (e.g., knotless weak links in buoy lines for lobster traps and gillnets, no floating line at the surface) to reduce risk of entanglement.
Utilize state and federal contacts for Whale Disentanglement Networks to locate entangled whales and remove gear. If you see an entangled whale, call the Northeast Disentanglement Network at 1-800-900-3622, the Coast Guard Station nearest you on 16 VHF Radio, the Maine Whale Take Reduction Coordinator, or the Maine Marine Patrol.
Investigate and implement measures to reduce ship strikes of whales, including: 1) routing ships around observed whales, 2) restricting speed of vessels operating in whale habitats, 3) requiring mandatory shipping lanes when transiting through critical habitat areas, and 4) providing ship captains operating in critical habitats with the latest whale sighting data.
Whale watchers must employ the following guidelines: 1) No vessel should approach closer than 300 yards. When whales are nearby, move at a constant, slow, "no wake" speed. 2) Do not engage props while whales are within 100 yards and do not chase whales. 3) When watching whales, do not box them in or cut off their path to prevent them from leaving. 4) Do not attempt to approach mothers with young calves. 5) Do not operate aircraft within 300 yards of a whale.
Plan for protection of critical whale habitats in state and federal oil spill contingency planning.

For more information contact Maine's Endangered Species Program at (207) 941-4466.

DEPARTMENT INFORMATION

Humpback Whale (Megaptera novaeangliae)