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Wednesday 04 March 2009
by: Moises Velasquez-Manoff
When
scientist Dee Boersma first arrived to Punta Tombo, Argentina, in the
early 1980s, the colony of Magellanic penguins there was 300,000
breeding pairs strong. Since then, they've declined by more than 20
percent. Dr. Boersma faults competition from fishermen, pollution in
the form of oil dumped at sea, and climate change for the decline.
But while the Punta Tombo colony is shrinking, others
farther north are growing. The penguins' shifting range underscores how
climate change isn't always a drop-dead-from-the-heat affair. And it
raises questions about how to protect threatened - and mobile - marine
species as they adjust.
Changing weather patterns have shifted upwelling currents,
the productive areas that support large anchovy schools, northward. On
average, Punta Tombo penguins must now swim 25 miles farther for a meal
- 50 miles total - compared with a decade ago. Some penguins have
simply established new colonies closer to their food source, welcome
evidence of their ability to adapt.
But the move also worries Boersma: At Punta Tombo, the
penguins are protected. In their new colonies farther north, on private
land, they're not.
The aquatic birds' exodus from a safe haven highlights a
quandary presented by a changing world: How do people, with their
landlubber bias, protect and manage marine ecosystems that, by
definition, go with the flow?
"We set aside parts of the world as if it's going to be
static," says Boersma, at the University of Washington, Seattle. "But
the one thing that's constant is change."
So far, few - and maybe none - of the more than 4,500
marine protected areas (MPAs) established worldwide have been
explicitly designed to cope with climate change and the issues
exemplified by the Magellanic penguins, say experts. Getting protected
areas drawn on a map is hard enough, they note. Establishing one that
moves or adjusts with changing conditions - a roving MPA - will be
harder still.
But some are already thinking about how to design MPAs that
still function as climates change. Maybe they're bigger, say
scientists, or spaced like stepping stones so species can hopscotch to
higher latitudes. Perhaps they're not tied to a geographic location at
all, but follow conditions scientists know are important.
New technologies for tracking marine species and people,
and more sensors to monitor conditions at sea now make what was once
impossible at least theoretically possible. Questions of governance and
human bureaucracy are the greater challenge, scientists say.
"It's really sort of a fundamental challenge to how we've
been doing conservation until now," says Emily Pidgeon, lead adviser
for Conservation International's Marine Climate Change Program in
Arlington, Va. "But it's not a completely hopeless story. This requires
us to change ideas and go to Version 2.0. But we can do that."
As human impact on the world's oceans has become more
readily apparent, scientists have pushed harder for the creation of
marine protected areas. Ecosystems that are allowed to function
relatively unperturbed will be a kind of insurance policy against
species extinction and ecosystem collapse, the thinking goes.
Governments Have Heeded the Warning Somewhat
To some degree, governments have heeded the warning. Former
President George W. Bush created two large MPAs in the Pacific at the
end of his tenure. Island nations in the Pacific and Caribbean, among
others, have also established MPAs in recent years. California is
creating an MPA network that may, when complete, protect some 20
percent of state waters. Currently, just 0.7 percent of the world's
oceans enjoy even nominal protection, a far cry from the "20 to 30
percent protected by 2012" goal declared at the fifth World Parks
Congress in 2003. Yearly, protected ocean increases by about 5 percent.
Already, scientists are observing shifts in species
distribution around the world. After an 800,000-year absence, a species
of Pacific diatom, a shell-encased alga, has recently appeared in the
North Atlantic. Scientists are unsure of its impact, but they take its
arrival as evidence that certain conditions absent for nearly a million
years - lack of sea ice, prevailing winds - are reemerging.
Northern countries like Norway and Iceland have seen an
influx of more southerly fish species. They're not complaining, because
they're likely to catch more fish. Blue mussels, once found only as far
north as Norway's coast, meanwhile, have colonized the Svalbard
archipelago, more than 400 miles from Scandinavia.
Salmon spawn in ever more northerly Alaskan rivers. And
walleye pollock, the largest US fishery by volume, appear to be
shifting into Russian waters. This development has implications for
both US fishermen and stock health, says Daniel Pauly, a fisheries
professor at the University of British Columbia, Vancouver. In US
waters, pollock is carefully managed, he says - but not in Russian
waters.
If a fish stock moves out of a particular area, he says, it
takes much more time to work out new international fishing treaties
than it does to fish down the stock.
Indeed, unsure about how much fishing newly accessible
Arctic waters can sustain, in February, the US North Pacific Fishery
Management Council approved a moratorium on fishing in the US Arctic
pending more studies.
A recent study in the journal Fish and Fisheries concluded
that, broadly speaking, these trends will continue during this century.
Higher latitude waters will continue to see an influx of lower-latitude
species, and, most likely, a corresponding increase in catches.
Lower-latitude developing countries, on the other hand, where many
people still subsist on fish, will lose species. Semienclosed oceans
like the Mediterranean and the Gulf of Mexico are likely to see local
extinctions.
"For people who are doing conservation or fishery
management, they should not think of the ocean as static or
unchanging," says William Cheung, a researcher with the University of
British Columbia and lead author on the Fish and Fisheries study. "They
should think of it as changing."
But local changes due to a changing global climate can be
unpredictable. Cornell University scientist Charles Greene has found
that waters off the Northeastern US paradoxically cooled during the
1990s, for example. Melting permafrost, sea ice, and more precipitation
at higher latitudes - all attributable to a warming climate - increased
freshwater influx into the Arctic. That cold, low-salinity water then
flowed south along the Eastern Seaboard, perhaps impeding the recovery
of overfished cod stocks and affecting marine ecosystems as far south
as North Carolina.
Greater extremes of wet, hot, and dry are "the dirty secret
behind climate change," says Pidgeon. El Niño, a periodic warming of
surface waters in the eastern Pacific that scientists think will become
more frequent in a warmer world, halts the upwelling that fuels many
marine ecosystems. On the Atlantic side, Boersma has noted that heavier
and more frequent rainfall, which can flood penguin nests, lowers their
reproductive success.
What Needs to Be Done?
Preparations for a changing marine environment include
making reserves bigger in anticipation of a general shift toward the
poles, say scientists. Better yet, design marine reserves as networks,
like California's, so critters can hop poleward on "what you might
think of as steppingstones," says Dennis Heinemann, a senior scientist
with the Ocean Conservancy in Washington, D.C.
Protecting habitat critical to keystone species will also
help. California kelp, for example, needs a hard substrate. To aid its
migration, rocky areas along the way should be protected.
Another strategy: Protect places known to be important at
crucial stages of critters' life cycles. The ice's edge in the Arctic,
for example: Marine mammals use it as a staging area for hunting and
foraging. The long-ranging bluefin tuna could be protected while it
spawns in the Gulf of Mexico.
That might mean shutting down or restricting fishing in an
area during a certain period of the year. Migrating species like whales
and sea turtles ride currents. Removing shipping traffic and fishing
from these sea highways during migration periods would lessen
mortality.
There are some precedents for these approaches. Some
migrating birds enjoy protected nesting grounds and wintering grounds,
but nothing in between, and that suffices, says Pauly.
New Technologies Will Play Pivotal Role
But as these protected areas will be pegged to ocean
conditions rather than geographic locations, new technologies will
necessarily play a pivotal role.
Satellites can see high concentrations of chlorophyll -
blooms of algae - and help scientists infer where upwelling is
occurring and where feeding grounds are likely to be.
Endeavors like the National Science Foundation's Ocean
Observatories Initiative, which scientists will soon begin putting in
place, will increase the number of sensors at sea and vastly improve
humans' ability to see what's happening where and adjust accordingly.
New smaller fish tags, meanwhile, have already revealed a lot about when, where, and why fish migrate.
"We're sort of getting a fish's eye view of the undersea
world," says Cornell's Greene. "The biology gives us a really strong
signal that enables us to look for things that sometimes slip past the
physical oceanographers."
GPS-enabled Vehicle Monitoring Systems, common on boats,
will play an important role both in enforcement, and in helping boats
navigate around MPAs of complex shape of shifting location. (They've
historically been mostly square-shaped, though ecosystems typically
aren't, partly to make them easier to avoid.)
But the more difficult question is political. Where will
plans for species that cross national borders be hammered out? How will
nations manage the high seas where, currently, there's little
governance beyond a nation's 200-mile wide exclusive economic zone?
One model: The 25-nation Commission for the Conservation of
Antarctic Marine Living Resources governs fishing, especially that of
krill, in the Southern Ocean. Another model: Colombia, Ecuador, Costa
Rica, and Panama have agreed under the San José Declaration to manage
jointly the marine species that migrate among the nations' waters
together.
"Those sorts of approaches are going to have to become more common," says Pidgeon.
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