Species Description Humpback whales are
well known for their long pectorial fins, which can be up to 15 feet (4.6 m) in length. Their scientific name,
novaeangliae, means "big-winged New Englander" as the New England
population was the one best known to Europeans. These long fins give them
increased maneuverability; they can be used to slow down or even go backwards.
Similar to all baleen whales, adult
females are larger than adult males, reaching lengths of up to 60 feet
(18 m). Their body coloration is primarily dark grey, but individuals have
a variable amount of white on their pectoral fins and belly. This variation is
so distinctive that the pigmentation pattern on the undersides of their
"flukes" is used to identify individual whales, similar to a humans
Humpback whales are the favorite of
whale watchers, as they frequently perform aerial displays, such as breaching
(jumping out of the water), or slap the surface with their pectoral fins,
tails, or heads.
In the summer, humpbacks are found in
high latitude feeding grounds such as the Gulf of Maine in the Atlantic and
Gulf of Alaska in the Pacific. In the winter, they migrate to calving grounds
in subtropical or tropical waters such as the Dominican Republic in the
Atlantic and the Hawaiian Islands in the Pacific. The Arabian Sea humpback,
however, does not migrate, remaining in tropical waters all year.
Humpback whales travel great distances
during their seasonal migration, the farthest migration of any mammal. The
longest recorded migration was 5,160 miles (8,300 km). This trek from
Costa Rica to Antarctica was completed by seven animals, including a calf. One
of the more closely studied routes is between Alaska and Hawaii, where
humpbacks have been observed making the 3,000 mile (4,830 km) trip in as
few as 36 days.
During the summer months, humpbacks
spend the majority of their time feeding and building up fat stores (blubber)
that they will live off of during the winter. Humpbacks filter feed on tiny
crustaceans (mostly krill), plankton, and small fish and can consume up to
3,000 pounds (1360 kg) of food per day. Several hunting methods involve using
air bubbles to herd, corral, or disorient fish. One highly complex variant,
called "bubble netting,"
is unique to humpbacks. This technique is often performed in groups with
defined roles for distracting, scaring, and herding before whales lunge at prey
corralled near the surface.
In their wintering grounds, humpback
whales congregate and engage in mating activities. Humpbacks are generally "polygynous" with males exhibiting competitive behavior on wintering grounds. Aggressive and
antagonistic behaviors include chasing, vocal and bubble displays, horizontal
tail thrashing, and rear body thrashing. Males within these groups also make
physical contact; striking or surfacing on top of one another. These bouts can
cause injuries ranging from bloody scrapes to, in one recorded instance, death.
Also on wintering grounds, males sing complex songs that can last up to 20
minutes and be heard 20 miles (30 km) away. A male may sing for hours,
repeating the song several times. All males in a population sing the same song, but that song
continually evolves over time. Humpback whale singing has been studied for
decades, but scientists still understand very little about its function.
Gestation lasts for about 11 months. Newborns are 13 to 16 ft
(4 to 5 m) long and grow quickly from the highly nutritious milk of their
mothers. Weaning occurs between 6 and 10 months after birth. Mothers are
protective and affectionate towards their calves, swimming close and frequently
touching them with their flippers. Males do not provide parental support for
calves. Breeding usually occurs once every two years, but sometimes occurs
twice in three years.
Habitat During migration, humpbacks stay near the
surface of the ocean.
While feeding and calving, humpbacks
prefer shallow waters. During calving, humpbacks are usually found in the
warmest waters available at that latitude. Calving grounds are commonly near
offshore reef systems, islands, or continental shores.
Humpback feeding grounds are in cold,
productive coastal waters.
Distribution Humpback whales live in all major
oceans from the equator to sub-polar latitudes.
In the western North Atlantic ocean,
humpback whales feed during spring, summer, and fall over a range that
encompasses the eastern coast of the United States (including the Gulf of
Maine), the Gulf of St. Lawrence, Newfoundland/Labrador, and western Greenland.
In winter, whales from the Gulf of Maine mate and calve primarily in the West
Indies. Not all whales migrate to the West Indies every winter, and significant
numbers of animals are found in mid- and high-latitude regions at this time.
In the North Pacific, there are at
least three separate populations:
stock winters in coastal Central America and Mexico and migrates to areas
ranging from the coast of California to southern British Columbia in
Central North Pacific
stock winters in the Hawaiian Islands and migrates to northern British
Columbia/ Southeast Alaska and Prince William Sound west to Kodiak; and
Western North Pacific
stock winters near Japan and probably migrates to waters west of the Kodiak
Archipelago (the Bering Sea and Aleutian Islands ) in summer/fall. There is
some mixing between these populations, though they are still considered
In the Southern Hemisphere, the International Whaling Commission (IWC) has
designated seven major breeding stocks linked to seven major feeding areas.
Most breeding areas for Southern Hemisphere humpbacks are at 20°S, although
some are in the Northern Hemisphere, including areas along the west coast of
Africa and Central America. In Costa Rica, there is overlap with Northern
Hemisphere humpbacks geographically, but they are not there at the same time.
All Southern Hemisphere humpbacks share feeding grounds in the Antarctic south
of 40°S and between 120°E and 110°W.
Population Trends Humpbacks are
increasing in abundance in much of their range.
In the Southern Hemisphere, humpback
abundance prior to commercial exploitation is estimated at 100,000 whales.
Including illegal unreported Soviet whaling, there were an estimated 200,000
Southern Hemisphere humpback whales harvested from 1904-1980. The current
Southern Hemisphere population may be over 25,000 whales although we have
little data on which to base this estimate.
In the North Pacific, humpback
abundance was estimated at fewer than 1,400 whales in 1966, after heavy
commercial exploitation. The current abundance estimate for the North Pacific
is about 20,000 whales.
For the North Atlantic, the best
available estimate is 11,570 whales.
No current or historical abundance
estimates are available for humpbacks in the Indian Ocean.
While estimating humpback whale
abundance is inherently difficult, the best estimates for minimum populations
for the five stocks of humpback whales recognized in U.S. waters are:
Gulf of Maine stock in
the Atlantic Ocean - about 550
Western North Pacific
- about 365
Central North Pacific
(including the Southeast Alaska feeding area) - about 3,700
- about 1,250
American Samoa - about
The Gulf of Maine, central North
Pacific, and California/Oregon/Washington stocks seem to be increasing.
There is not enough information to
accurately assess population trends for the western North Pacific and American
Threats Humpback whales face a series of threats
including entanglement in fishing gear (bycatch), ship strikes, whale
watch harassment, habitat impacts, and proposed harvest.
Humpbacks can become entangled in
fishing gear, either swimming off with the gear or becoming anchored. NOAA
Fisheries has observed incidental intake of humpback whales in the California/Oregon swordfish and thresher shark drift
gillnet fishery. Potential entanglement from gear from several fisheries can
occur on their long migration from Hawaii to Alaska. Humpbacks in Hawaii have
been observed entangled in longline gear, crab pots, and other
Inadvertent ship strikes can injure or
kill humpbacks. NOAA Fisheries has verified mortality related to ship strikes
in the Gulf of Maine and in southeastern Alaska. Ship strikes have also been
reported in Hawaii.
Whale watching vessels may stress or
even strike whales. The Gulf of Maine stock is the focus of whale watching in New
England from late spring to early fall, particularly within the Stellwagen Bank National Marine Sanctuary. The central
North Pacific stock is the focus of a whale-watching industry on their
wintering grounds in the Hawaiian Islands. The
feeding aggregation in southeast Alaska is also the focus of a developing
whale-watching industry that may impact whales in localized areas.
Shipping channels, fisheries, and aquaculture
may occupy or destroy humpback whale aggregation areas. Recreational use of
marine areas, including resort development and increased boat traffic, may
displace whales that would normally use that area. In Hawaii, acoustic impacts
from vessel operation, oceanographic research using active sonar, and military
operations are also of increasing concern.
While there is no current legal
commercial harvest of humpback whales, there is interest by some countries to
resume humpback harvest. Japan has proposed killing 50 humpback whales as part
of its program of scientific research under special permit (scientific whaling)
called JARPA II in the IWC management areas IV and V in the Antartic. Also, Denmark recently proposed a
hunt of 10 humpbacks a year off the coast of Greenland. Both of these proposed
harvests have the potential to negatively impact recovery of humpback whales.
Conservation Efforts The most recent
conservation efforts by NOAA Fisheries and its partners are to:
Reduce bycatch in
gillnet and trap/pot fisheries in the western North Atlantic through the Atlantic Large Whale Take Reduction Plan.
mammal take reduction measures identified in the Pacific Offshore Cetacean Take
Mitigate ship strikes
and respond to humpback whales in distress (see Alaska nd Hawaii regulations).
Educate whale watch
vessels and boat operators on practicing safe boating around whales.
Monitor humpbacks in
U.S. waters via shipboard surveys and mark recapture studies.
population structure and abundance including the Structure of Populations, Levels of Abundance and Status of Humpbacks (SPLASH) and More North Atlantic
Humpbacks (MoNAH) projects as well as work done at the Hawaiian Islands Humpback Whale National Marine Sanctuary.
In 1991, NOAA Fisheries published the Humpback Whale Recovery Program.
Regulatory Overview In 1946, the
International Convention for the Regulation of Whaling regulated commercial
whaling of humpback whales. In 1966, the International Whaling Commission
prohibited commercial whaling of humpbacks. In June 1970, humpback whales were
designated as "endangered" under the Endangered Species Conservation
Act (ESCA). In 1973, the Endangered Species Act (ESA) replaced the ESCA, and
continued to list humpbacks as endangered.
In 1972, humpbacks were provided additional protection under the
Marine Mammal Protection Act (MMPA), and were considered "depleted"
in 1973. Under the MMPA, threats to humpbacks are mitigated by regulations
implementing the Pacific Offshore Cetacean Take Reduction Plan and the Atlantic Large Whale Take Reduction Plan.