Glacier
Bay National Park
Whale WatchingSeeing huge whales
in their native habitat counts as
one of life's great experiences.
Each summer 15-20 humpback whales
regularly feed in park waters,
concentrating in the lower part of
the bay. They migrate here from
their winter home in the warm waters
off Hawaii and can often be seen
along the shorelines of Southeast
Alaska. Special regulations go into
effect when large concentrations of
whales are in the park. The
regulations affect vessel speed
limits and travel routes in certain
areas.
Humpback whales are the most
acrobatic of whales, heaving their
massive selves by leaps and turns
out of the water. Humpbacks are both
cosmopolitan—found in all oceans—and
endangered. Only about seven percent
of their pre-whaling numbers remain.
Coastal feeders who love shorelines,
bays, and fjords, they are naturals
for Alaska, which boasts nearly
34,000 miles of tidal shoreline.
Humpbacks feed here on krill,
shrimp, and various fish, including
capelin. Humpbacks feed heavily
because, unlike most birds and
mammals, they do not feed year
round. Humpbacks must store enough
fat in summer to last the rest of
the year. Adults average 40 to 50
feet long, females being the larger.
Adults weigh in at about
three-quarters of a ton per running
foot.
An adult humpback has from 600 to
800 baleen plates in its mouth.
These plates end in bristles. In the
feeding process, huge masses of sea
organisms are scooped into the
mouth. Then the water, some 150
gallons at a shot, is expelled while
the plates filter in the edibles.
Were you to stare into a humpback's
mouth— which opens to 90 degrees—
you might not readily discount the
Biblical mishaps of Jonah. Glacier
Bay humpbacks have been observed
working singly or in pairs to cast
a"net" of bubbles about their prey
and then harvesting the hapless
creatures—probably shrimp and other
slower-moving organisms—caught in
their airy illusion.
Whales include the largest creatures
our world has known. Blue whales
weighed up to 200 tons before
whaling days. Sixty to 100 million
years ago the ancestors of today's
whales were land dwelling,
warm-blooded, air breathing mammals
who successfully returned to the
seas to live. Alaskan waters boast
10 species of baleen whales and 5
toothed whales. Glacier Bay waters
boast 2 of the baleen whales, the
minke and humpback, and 1 toothed
whale, the orca. The whales' appeal
mixes familiarity and strangeness.
Whales live in family groups, aid
each other in distress, and talk to
each other. Some serious observers
credit whales with rational thought.
Minke whales are thought to be quite
migratory and are more at home in
cold northern waters than most
baleen whales. (Baleen whales are
named for how they feed). Cod and
pollock are their main diet here.
Farther south minkes favor krill.
The upper size limit of minke whales
in northern waters is 33 feet. Among
large whales, minkes are fast
swimmers, making speeds up to 20
miles per hour. As whaling has
depleted more favored species, the
rich-meated minke has become the
most often killed baleen whales.
Their North Pacific population
appears to have declined to between
one-fourth and one-third its
pre-whaling numbers.
Orca whales feed on various marine
animals, including fish, sea lions,
seals, porpoises, sharks, squid, and
other whales. Also called killer
whales, orcas can hunt in teams and
have killed blue whales, the world's
largest animals. Male orca whales
average about 23 feet long; the
females less. They have no natural
enemies. Thought to be highly
intelligent, orcas are readily
trained in captivity. They can swim
at a steady 29 miles per hour. Their
distinctive, largely triangular
dorsal fin may reach nearly 6 feet
high on old males.
The situation of whales, and
particularly of the endangered
humpback whales, in Glacier Bay has
recently been under intensive
scrutiny by scientists. The purpose
of the studies has been to learn
enough about these awe-inspiring
creatures to protect them. The
numbers of whales present can vary
dramatically from year to year.
Whether these variations are wholly
natural or not is uncertain.
Historically, most of our
information about whales derives
from attempts to harvest them, not
to save them from extinction.