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Gray Whale
©Dave Weller/IUCN
Who Ever Heard of a Skinny Whale?
Western gray whale.
Researchers
Gray Whale
think that
Scientific name: Eschrichtius robustus
warming in
Gray whales of the eastern North Pacific Ocean follow the longest annual migration
route of any marine mammal, an astounding 12,000 miles round-trip. They travel
from Arctic waters and the North Pacific to the warm waters off the coast of Baja
California in Mexico and back again. In the 19th century, whalers nearly wiped out the
population, easily cornering and killing large numbers of mothers and calves as they
rested in lagoons that serve as their nurseries on the Baja California coast.
the Arctic could
be reducing
the gray whale
food supply.
Less food for
gray whales has
lead to “skinny
whales.”
©2008 Ocean Conservancy
Scientists estimate that gray whales in the Eastern North Pacific group now number
about 20,000. (A second population of gray whales inhabits the Western North Pacific).
While it appears that the species has partially recovered from the severe effects of 19thcentury industry, current research indicates that, before whaling, there were three to five
times more gray whales than swim the ocean today. What’s more, over the past several
years, large numbers of these whales have died mysteriously—more than 300 died in
2000 alone—and scientists are trying to figure out why.
Easily identified by their mottled gray color, these whales are notable for the clusters
of barnacles that cling to their skin; they can host up to a hundred pounds of these
distinctive hitch-hikers.
At birth, a calf weighs about 1,300 pounds and spans
15 feet head-to-tail. Adults reach four to 50 feet in
length, and weigh up to 80,000 pounds, with females
growing slightly larger than males. However, lately
Eschrichtius robustus isn’t so robust. Gray whales can
live for half a century, but global climate change may
be cutting lives short.
Skinny whales
Researchers have observed increasing numbeers of
malnourished gray whales, and think that warming in
the Arctic could be reducing their food supply. Less
food for gray whales has led to skinny whales.
During the summer months, gray whales inhabit the
coastal waters of the North Pacific Ocean, including
the Bering and Chukchi Seas, where they forage in
the nutrient-rich waters and store up energy; this
energy sustains them during migration and calving.
They won’t eat again until they return north. Gray
whales eat up to 2,000 pounds of food a day. They
filter their food from the water through comb-like
baleen; unlike most other baleen whales, they
feed mostly on the bottom, sucking up tiny ocean
organisms like crab larvae. But as Arctic ecosystems
change because of a changing climate, organisms
living on the ocean floor have declined. And whales
are going hungry.
In response to the lack of food, malnourished whales
are shifting their migration schedule, which in turn
impacts their young. During migration, they can swim
about a hundred miles a day, surfacing for air every 15
minutes. Normally, they leave their northern foraging
grounds in late September or early October and they
arrive near Baja California, Mexico, around January.
But because they can’t get enough calories to sustain
themselves in the north, hungry whales are feeding
longer there and leaving later for their southern
migration. Delayed arrival in the lagoons means they
have less time there to breed and nurse their young.
Melting ice is increasing accessibility further north
Melting ice is opening routes into the northern
Arctic– for whales and humans. Whales that usually
stay south of the Bering Strait are now able to
make their way farther north into the Beaufort Sea.
Although they do find plentiful prey in these waters,
gray whales have to expend more energy and time to
travel north– another factor at may be contributing to
their weight loss.
Humans are also gaining more access to the Arctic
as ice melts. Expanded oil and gas exploration would
increase threats to the gray whale’s critical habitat
in the North, increasing the chances of oil spills
and collisions with ships as well as highly disruptive
noise. The loud pulse of seismic techniques used for
oil and gas exploration occurs at frequencies that
overlap with gray whale calling frequencies, potentially
interfering with socialization, reproductive behavior,
and communication.
Additional threats to the gray whale include
entanglement in fishing gear and illegal fishing in the
Western Pacific.
What Ocean Conservancy is doing to help
Ocean Conservancy supported a provision passed by
Congress that would require and authorize funding
to study unexplained gray whale deaths. We are
working with the US and Mexican governments
to provide technical assistance and training to
undertake these studies.
What you can do to help
The future of gray whales depends upon their ability to
adapt to the numerous changes in their environment,
many of which result from human activities. A healthy
gray whale population can survive into the future if we
all take steps to help.
•
Encourage lawmakers and Congress to
enact more stringent rules to protect the
gray whale – sign up for the Ocean Action
Network at www.oceanconservancy.org/oan.
•
Consider taking part in the numerous gray
whale counts off of the Pacific coast.
•
Fight global climate change: Create a map of
your carbon footprint and find ways to reduce
fossil fuel use.
•
Let legislators know we must protect not just
individual species like the gray whale, but the
entire Arctic ecosystem.
Gray Whale • Page 2