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For information on the Harriman Retraced Expedition e-mail: harriman2001@science.smith.edu |
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I don't give a damn if I
never see any more scenery. My story begins in Dutch
Harbor/Unalaska, the logistic gateway to the Bering Sea. I
first came to Dutch Harbor 27 years ago, to join a research
cruise. The first ocean-ecosystem research in the region was
just beginning. The town differed then from the remote but
modern community, which the Harriman Expedition Retraced
participants visited in August 2001. In 1974, it was a
primitive settlement that probably was more like its
condition in 1899 than how it is today. There was no bridge
between Unalaska and Dutch Harbor, and the magnificent
Russian Orthodox Church had fallen into disrepair, just one
symptom of decay among many. The bars were lively,
though. Selected
Bibliography [1] Boltnev, A. I. 1996.
Status of the Northern Fur Seal (Callorhinus ursinus)
Population of the Commander Islands. In Ecology of the
Bering Sea: A Review of Russian Literature. O. A. Mathisen
NS K. O. COYLE, EDS. University of Alaska Sea Grant Collage
Program Report 96-01 [3] Amphipod
means many legs. [4] National Research
Council, Committee on the Bering Sea Ecosystem. 1996. The
Bering Sea Ecosystem. National Academy Press. Washington,
D.C.307 pp.
For information on the Harriman Retraced Expedition e-mail: harriman2001@science.smith.edu
Expedition
Log
When the Harriman Expedition arrived in 1899, the town was a
transportation hub for gold miners; the Pacific cod fishery
was probably underway at the time as well. The harvest of
sea otters, the original focus for the town, was over; the
Bering Sea northern fur seal industry was still alive.
Today, the port serves the pollock, crab, and other
fisheries. The Harriman Retraced members also noted several
large foreign vessels in port for repair or being held for
fisheries violations.
Yes, Dutch Harbor has served as a transportation hub and
military base (remnants of World War II military
installations could be seen on the mountainsides when I
first came to the town, and are there still), and the
surrounding grasslands have been used for grazing cattle.
Yet, regardless of the transitory importance of these
functions, the town has always reverted to the commercial
harvesting of the sea's resources as the primary economic
basis for its existence. When the Clipper Odyssey arrived,
it was leaders in the fishing industry who accompanied the
mayor in welcoming us, and with whom we had a stimulating
panel discussion onboard.
Throughout its history, Dutch Harbor/Unalaska has played an
important role in supporting the harvest of the rich
biological resources of the Bering Sea and northern Gulf of
Alaska. Only days before the Clipper Odyssey approached
Dutch Harbor on August 6, 2001, our first stop in the Bering
Sea, the National Marine Fisheries Service had rated the
port as number one in fish catches for the previous year for
the entire United States. Along with New Bedford,
Massachusetts, and Kodiak, it was also among the top three
fishing ports in dollar value of the catch landed. Its
strategic location at the base of the Aleutian Chain and its
protected harbor have produced a prosperous community
central to a variety of activities, fulfilling the
prediction expressed by John Muir in his report of the
cruise of the Corwin, as he described his arrival at
Unalaska in May, 1881: By virtue of its geographical
position, it is likely to remain for a long time the
business center of Western Alaska.
At the same time, the fishing industry all the way from
Kodiak to Dutch Harbor has been under constraints imposed by
the plight of the western stock of the Steller sea lion
(Eumetopus jubatus). The stock has been declining
precipitously for three decades and is now classified as
endangered under the Marine Mammal Protection Act. A
controversial biological opinion released by the National
Marine Fisheries Service in 2000 has resulted in closure to
commercial fishing of numerous areas near rookeries or
haul-outs.
The first Russian explorers of the area opened the gates to
ruthless harvesting over the decades to come. Arriving in
1759, they were the first Europeans to report the existence
of what is now known as Unalaska, which subsequently became
the first permanent Russian settlement in Russian America.
In 1776, Gregory Pribilof had discovered the islands that
are named after him, and much of the hunting pressure became
focused there[1].
By the time the Harriman expedition visited in 1899, the fur
trade had wreaked havoc with the sea otter and northern fur
seal (Callorhinus ursinus) populations. The stocks had been
nearly wiped out by the Russian fur trade; after Alaska
became the property of the United States, the renewed fur
harvesting completed the devastation. Even by 1830, less
than 100 years after Bering's voyage, sea otters had become
so rare that Baron von Wrangell of the Russian American
Company persuaded his government to forbid the use of
firearms and to protect the remaining animals by rigid
conservation measures. This near-extermination was followed
by intensive and lucrative whaling, later accompanied by
intensive fishing.
Our more modern exploitation presents a grim picture as
well. When I first came to Dutch Harbor as a junior
oceanographer, the king crab fishery was still in its prime.
By the late 1970s, however, the king crab population had
crashed, probably as a result of overharvesting and climate
change. The pollock populations had increased dramatically,
and the pollock fishery was underway. First an international
fishery, today it is solely a United States fishery, with
split allocations between shore-base processors and the
large factory trawlers that both catch and process the fish
at sea. The total catch accounts for more than half the
total United States fish catch in a year. There are many
wealthy fishing captains in Dutch Harbor, and processing
plants produce large amounts of frozen fish and surimi, a
purified fish product used for making analogs such as
artificial crab legs. The Bristol Bay sockeye salmon fishery
is another major component, as has been the snow crab
fishery.
Contemporary paradigms hold that historical overfishing can
have long-term effects, showing up decades, even centuries
later[2]. Perhaps the history of the Bering Sea
provides a good case study for this, for without a doubt
man's activities over the years have had a large impact on
its ecosystem, albeit we still do not know to what extent
natural cycles control the ups and downs of the
populations of the various species. Yet, the Bering Sea
remains one of the most productive marine areas in the
world. The region includes the world's most extensive
eelgrass beds; at least 450 species of fish, crustaceans and
mollusks; 50 species of seabirds; and 23 species of marine
mammals.
Lying between the Arctic Ocean and the North Pacific Ocean,
the world's third-largest semi-enclosed sea, the Bering Sea
has properties of each and is influenced by both. It is
neither truly polar nor typically north temperate in
character. Most of its wide eastern shelf is extremely
shallow, in many places less than 60 meters in depth,
whereas the basin exceeds 3,000 meters in depth. About half
of the Bering Sea is underlain by continental shelf, and the
other half is a deep basin. Several huge undersea canyons
run up from the basin onto the shelf.
What factors account for the high productivity and species
diversity of the Bering Sea? A look at the world's fish
catches, historical and contemporary, shows that the richest
and most productive fishing grounds usually are found in
hostile subarctic or northern temperate areas, where the
weather is invariably unpredictable and nasty. The Bering
Sea is no exception, except that arguably it is the most
productive of them. Fishing under these conditions is
hazardous, and in these waters disasters are inevitable.
Members of the original Harriman Expedition spent a great
deal of time suffering from the seasickness that is
inevitable under these conditions, albeit this is a
relatively minor problem when compared with the frequent
loss of vessels and life.
Why are highly productive areas so inhospitablecold and
stormyor, to reverse the question, why are cold, stormy
seas highly productive? The Harriman Expedition had no
oceanographers onboard. Oceanography had not yet become a
science, and the concept of ecosystems had not yet arisen
either. While the inclement conditions were noted, their
significance was not recognized.
Today, we have some understanding of the forces that drive
marine productivity, but even more important, we have
marvelous new tools to study them, including satellite
technology. If you look at a satellite ocean color-scan
image of the distribution of plants in the oceans in spring
throughout the northern hemisphere, you notice immediately
that there is no other region as rich as the Bering Sea.
Why? The answer lies in cold northern water meeting water
moving up from the south. In the Bering Sea, some of the
water that moves up onto the shelf is from the deep Pacific
Ocean and carries a very high nutrient content. This
produces the green belt, a zone of high plant growth
along the outer Bering Sea shelf. A major driving force for
all of this is the northward passage of water through the
Bering Strait over the Chukchi Sea shelf and into the Arctic
Ocean. Ultimately, this water moves into the North Atlantic
Ocean via the East Greenland Current. This flow is driven by
a difference in height between the Pacific and Atlantic
Oceans.
To explore the Bering Sea part in a little more detail,
water flowing along the coast of the Gulf of Alaska passes
through Unimak Pass as well as other passes west through the
Aleutian Chain and then north and west up onto the shelf,
bathing the Pribilof Islands and the outer portions of the
shelf with nutrient-rich water that supports the diverse and
abundant biota in the area. This flow, prior to moving into
the Bering Sea, also supports the fishery resources in
Shelikof Strait and the Kodiak area.
In the Bering Sea, nutrient-rich water is transported onto
the shelf through eddies and tidal action as well, and via
canyons that transect the edge of the shelf. The Pribilof
Islands lie in the path of, and are influenced by, this
nutrient-rich flux. The islands also benefit from the
trapping of materials in the surrounding shallow waters
through tidal action.
After leaving Dutch Harbor, as we approached Bogoslof
Island, the Harriman Retraced participants observed large
numbers of Steller sea lions and northern fur seals on the
rookeries. This island lies over deep water at the edge of
the shelf. Compared to its appearance in photographs taken
by Harriman photographer Edward S. Curtis, the modern island
shows major erosional changes. What we couldn't see from our
Zodiacs was that deep below us was one of the most important
spawning areas for walleye pollock. The juvenile pollock
move up onto the shelf to grow, making use of the rich food
sources and reducing the danger of cannibalism by the older
fish. Today, though, they face a new hazard. In the past
decade, the populations of a large jellyfish, Chrysaora
melanaster, have increased tenfold over the Bering Sea
continental shelf. These jellyfish compete for food with the
young pollock, and they also prey on them. The impact on the
pollock population is as yet not known. They may also be
affecting the salmon, which have been showing variable and
often disastrously low returns in the Bering Sea.
The Steller sea lion population of the region has been
declining for several decades, having undergone more than an
eighty percent reduction since 1965. In 1997 the population
was classified as endangered under the Endangered Species
Act. As a result, in 2001 a federal judge banned pollock
fishing in critical habitat adjacent to about 40 rookeries
and 82 haul-outs in the Bering Sea and western Gulf of
Alaska. In truth the effects of fishing and the removal of
large numbers of pollock on the sea lions is not well
understood, and therefore a precautionary approach has been
adopted.
Steller sea lions are not the only species that have shown
big changes in the Bering Sea. Northern fur seals, sea
otters, and several sea birds have experienced either steady
or episodic declines. Salmon returns have been very low
along the Bering Sea coast. Small runs of sockeye salmon in
Bristol Bay and of king salmon in the Yukon River have
created considerable hardship for both commercial and
subsistence fishers since 1997. Historical exploitation
could be the cause of these declines, but most likely
dramatic climate shifts have played a role as well. One
major shift occurred in the late 1970s, with an accompanying
increase in temperature and a significant decline in
seasonal sea ice cover. The latter is important, because the
sea ice, as it retreats in spring, creates an early plant
bloom that provides a large input into the ecosystem. The
warmer waters with reduced sea ice grew warmer still in
response to the 1997-98 El Niño, and there was a
reduction in nutrient input from the south. Evidence points
to lower overall productivity, not just in the southeast
shelf region, but all the way up to the Bering Strait,
although a change in timing and distribution is more likely,
bringing about changes in the food chain. Another unusual
occurrence was a massive invasion of exotic calcium-bearing
algae, coccolithophorids, in 1997. These turned the water
into a milky white fluid over four summer seasons; traces
have been noted in 2001 as well.
As Harriman Retraced moved northward and across the
international dateline into Russian waters, the abundance of
large mammals, including walrus (Odobenus rosmarus) and gray
whales (Eschrichtius robustus), increased, tallying with our
understanding of the distribution of primary production
(plant production) in the Bering Sea. The rich Anadyr Water,
which originates from the westward flow mentioned earlier,
moves north toward the Bering Strait, hugging the coast of
the Chukchi Peninsula. While there are very rich places in
the U.S. side of the northern shelf, such as the Chirikov
Basin and the southern Chukchi Sea, the entire Russian
portion is highly fertile. There, subsistence-based
communities have enjoyed the biotic wealth.
The northern Bering Sea is able to support very large
mammals such as resident walrus and migratory gray whales
(as well as large sea bird populations) because of the rich
organic deposits lain over the sea bottom by sinking
planktonic plant material over this shallow shelf. It is
primarily a bottom or benthic-based ecological
community; pelagic fishes are relatively unimportant here as
a resource. The biota which grow on the bottom, clams and
tube-dwelling crustaceans, present a stable food source,
accessible to walrus in winter from the ice surface and to
gray whales, which migrate from Baja California to feed on
the copious amphipods[3] (small crustaceans) in the
summer. That it is worthwhile, in a biological sense, for
the whales to migrate such vast distances to feed here
attests to the wealth of the available food. All this
richness is driven by the northern extension of the green
belt, driven by flow north through the Bering
Strait.
Harriman Retraced members visited villages on the United
States side of the Bering Strait that were almost entirely
dependent on a subsistence hunting-based economy. Both the
historic and contemporary villages on the Chukchi Peninsula
also showed evidence of the important role played by whales
and walrus in their lives. This region is unique, a place
where Asia and North America meet. The peoples who straddle
the region, too, have a close relationship.
The ecosystem of the Bering Sea has changed markedly during
the last three decades, and it is likely that change has
characterized this region for centuries. Scientists studying
the region point to evidence that the changes that have been
noted over the last two decades or so have been unusually
dramatic and attribute them at least in part to climatic
events, rather than to the short-term influence of
harvesting. The regime shift of the late 1970s, followed by
the huge El Niño of 1997-1998, may have produced
conditions that cannot easily reverse themselves. Still, it
is hard to believe that the amount of harvesting, from
whales to crab to pollock, has not had some influence, as
proposed by a National Research Council study of the Bering
Sea ecosystem[4].
Prediction about how the ecosystem may change in the future
remains confounded because the weather patterns are
controlled by multiple factors: Arctic, Aleutian, North
Pacific, and Siberian. We can ask, for example, whether the
decline in populations of several marine mammal species, the
increases in jellyfish, the unreliable salmon returns, and
the shifting productivity regime are symptoms of a unique
event, or does it recur on an as-yet unrecognized time
scale? Exciting research is being done on what once lived in
the oceans, and new techniques are being developed to
investigate the past. It is difficult, though, to look back
to the days of the Steller sea cow and deduce what the kelp
forests would have looked like then. Furthermore, residents
of the region were affecting the stocks well before the
white explorers came, and it is impossible to define
a pristine condition.
Not all the Harriman Retraced members may have realized how
extremely fortunate they were the Bering Sea put on a calm
mantle and allowed a careful and considered look at the
mammals and birds and coastal communities and sites. From
the glassy passage through Unimak Pass, the sunny visit to
Unalaska, and on north, we enjoyed balmy, calm conditions.
It is hard to imagine a more beautiful scene than the tundra
heath of St. Matthews Island vanishing up the hills into the
haze, or the jagged rocks at the ends of the beach, or the
old rusty shipwreck, which we encountered farther down the
coast. St. Matthews Island was once known as a site for huge
numbers of polar bears, and, although when we visited there
was a rumor that a polar bear was stranded on the island, in
recent years the light ice has not allowed major
colonization of the island by these ice-dependent mammals.
On May 31, 1881, members of the Corwin expedition were
unable to land because of heavy ice. Today, it is rare to
find polar bears on St. Matthew Island, and the sea ice has
retreated by late April or early May.
This region is often stormy, and while spectacular, the seas
are often not very comfortable. Our visit to the Bering Sea
took place under exceptional conditions, and the experience
was further enhanced by the knowledge that finally as a
society we are recognizing the profound effects that have
altered the Bering Sea ecosystem, and that governmental and
non-governmental organizations as well as Native communities
are taking steps to introduce improved conservation and
management measures. The Bering Sea is the focus of a great
deal of attention, and while we cannot change the course of
natural processes, we can develop an understanding and
sensitivity with respect to our role.
[2] Jackson et al. 2001. Historical Overfishing and
the Recent Collapse of Coastal Ecosystems. Science
293:629-638.
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