 
Many rarely observed conditions
occurred in the Bering Sea during the summers of 1997 and 1998,
including extensive die-offs of seabirds, rare algal blooms,
unanticipated low salmon runs, warmer than usual ocean temperatures,
and altered ocean currents and atmospheric conditions. These
changes prompted scientists from NOAA,
the federal agency that protects and predicts the nation's marine
resources and atmospheric environment, to convene an international
workshop in Seattle, Wash.
"People whose livelihood
depends on the Bering Sea need to know if these are fleeting
anomalies or persistent large-scale changes," said James
Balsiger, head of NOAA's Alaska
Fisheries Science Center. "Scientists want to determine
the cause of these unusual conditions and their portent for the
future of this national resource."
The eastern Bering Sea provides
almost half of the fish and shellfish caught in the United States.
Most of the catch comes from the continental shelf, a broad,
shallow area larger than the state of California, that borders
Alaska's western coast. Besides producing abundant fish and shellfish,
the shelf also supports large numbers of resident and migratory
birds and marine mammals.
A prominent theme of the workshop
was the implication of recent environmental changes on the management
of living marine resources. Reports from those attending the
workshop will now be available via the Internet for a broader
review and comment by U.S. and world environmental scientists.
"We wanted to bring together
scientists, environmentalists, administrators, resource managers,
native Alaskans, representatives of the fishing industry, and
others at this crucial time," said Eddie Bernard, director
of NOAA's Pacific Marine
Environmental Laboratory in Seattle. "During the workshop,
more than 75 participants shared information, proposed reasons
for these environmental changes, and suggested future research
needs. They also discussed ways to use Internet technology to
report news and facilitate communication."
Workshop participants reported
information related to the environmental occurrences. Atmospheric
processes in 1997, partially in response to El Niño, caused
clearer skies, calmer seas, and warmer sea temperatures than
normal in the eastern Bering Sea. "The warmest water temperatures
ever recorded on the eastern Bering Sea shelf occurred during
the summer of 1997," said Phyllis Stabeno, an oceanographer
at the Seattle lab.
The most striking event was the
appearance of extensive areas of milky, aquamarine water over
most of the shelf in 1997. The water's unusual color was caused
by a massive bloom of coccolithophores (a type of non--toxic,
microscopic marine plant). These blooms have never before been
observed in the Bering Sea for extended periods. The coccolithophores
replaced the normal summer plankton community. This replacement
made profound, but not well understood, effects on the rest of
the food chain. Despite different atmospheric conditions in 1998,
the bloom recurred.
Other recent changes in the ecosystem
included unprecedented mortality of short-tailed shearwaters
and unsuccessful reproduction rates for kittiwakes (both common
seabirds frequenting the area during summer). Salmon runs were
far below expected levels. The fish were smaller than average,
and traditional migratory patterns seemed altered. There was
an unusual sighting of Pacific white-sided dolphins in Bristol
Bay, and large numbers of baleen whales appeared on the shelf.
Taken together, these events show how responsive the ecosystem
is to climate and suggest that climate change would have a strong
effect on the ecosystem.
Although these unusual conditions
did not seem to have an immediate effect on the groundfish of
the area, they may impact future abundance. NOAA Fisheries surveys
in 1997 and 1998 located fewer young-of-the-year pollock than
in previous years. However, other studies conducted in 1998 suggest
that young pollock, in fact, were quite abundant but located
further onto the shelf than usual. This displacement could derive
from transport of pollock larvae northeastward from their spawning
area due to windy conditions during spring. Ramifications of
these recent changes won't be known for several years until the
young pollock mature into adult fish and are harvested.
An important task is to determine
linkages between the unusual conditions and the Bering Sea's
bountiful resources of salmon and pollock. Workshop participants
agreed that focused, long-term, integrated research is needed,
and recommended the recently written Draft Science Plan for the
Bering Sea Ecosystem. Incorporating traditional knowledge from
native communities into the information available to research
programs is also vital, scientists acknowledged. Participants
discussed the challenge of preserving the diverse populations
of fish, marine mammals, and birds in this highly variable environment.
NOAA scientists are seeking review
and input from scientists throughout the globe. A summary of
the workshop will be available December 31 on the Bering Sea
and North Pacific Ocean Web site http://www.pmel.noaa.gov/bering/.
For general Bering Sea information, including the Draft Science
Plan for the Bering Sea Ecosystem, please consult the Web site.
For specific information, contact Allen Macklin, FOCI Coordinator,
NOAA/PMEL, 7600 Sand Point Way NE, Seattle, Wash. 98115-0070,
206-526-6798 (voice), 206-526-6485 (fax), macklin@pmel.noaa.gov
(e-mail). |
