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One last chance to save coral
Humans have been destroying reefs for
centuries, but time is nearly up, scientists say
By
Daniel Kane
Aug. 14 — The late 17th century sea-farers who used
the mysterious sound of gigantic swimming turtles to navigate around coral
reefs would find these same reef ecosystems significantly changed for the worse
today. In another 30 or 40 years, the same reefs could be almost completely
destroyed, unless humans act now to aggressively protect them from further
human exploitation, scientists say.
THE 15 AUGUST ISSUE of the
journal Science published by AAAS, the science society, features a special
report on coral reefs. All sorts of records, from pirate’s logs to modern day
fish counts, reveal that humans have a long history of damaging reefs. Based on
this history, humans have one last chance to establish a sustainable
reef-protection strategy, according to the authors.
A TIMELINE OF DECLINE
Humans have been steadily damaging coral reefs
since the hunter-gatherer era of human history. Overfishing and pollution
run-off from land are not exclusively modern problems, according to one of the
four Science articles. These authors report that destructive and poisoning
practices are to blame for the steady decline in coral reefs that began with ancient
humans.
Researchers led by John Pandolfi from the National
Museum of Natural History, Smithsonian Institution in Washington laid out a
timeline of human history going from hunter-gatherers to the modern era. For
each of seven culturally defined periods from pre-human to present, the
researchers plotted the level of coral reef degradation.
Information from the earliest human interactions
with reefs came from fossil and archaeological records. Records and logs from
the ships of Christopher Columbus, Captain James Cooke and other European
explorers provided detailed descriptions of abundance and diversity of coral
reef ecosystems they encountered. From more recent eras, the researchers used
data from fisheries and modern ecological studies.
Large animals declined faster
than small animals, the researchers found. Free-living animals declined faster
than the architectural builders such as seagrass and corals. At the beginning
of the 20th Century, large carnivores, including sharks, and herbivores such as
manatees were already either depleted or rare in 80 percent of the examined
regions of coral reefs.
“Walking the plank isn’t as dangerous as it once
was,” said John Pandolfi, an author on two of the Science papers and a curator
at the National Museum of Natural History, Smithsonian Institution.
“If I was forced to walk the plank and jump into the
Caribbean tomorrow, it wouldn’t be that bad. Of course there is the risk of
drowning, but it’s not like the old days when the risk of being eaten by sharks
was so much greater,” explained Pandolfi.
While the ecological histories show that coral reefs
have been declining ever since humans discovered their bounty, Pandolfi is not
all gloom and doom, in his attitude or his predictions but believes there is
some hope for the future. However, a co-ordinated, aggressive, worldwide effort
must be implemented soon. Indonesian fishermen blast the top of
a reef, stunning the fish that survive and sending them floating to the surface
for easy capture. Click the Play button to see how reefs are destroyed by such
techniques.
CORAL REEFS AND FRIENDS
A coral reef’s bright colors come from the
single-celled algae called “zooxanthellae” that have a cooperative living
arrangement with corals. These colorful, primitive plants use the sun to
produce food that they share with the coral in return for shelter.
Coral reefs grow in the warm, shallow, clear waters
of about 100 tropical and subtropical countries. Reefs provide food and shelter
for fish and invertebrates critical to commercial fisheries. They also protect
nearby shorelines from erosion and attract the tourists that sustain economies.
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Invertebrate animals called corals
build the reefs that bear their name. Corals secrete the limestone that forms
the hard structure of coral reefs.
While the building of coral reefs takes many years,
storms and human activities can rapidly destroy them. Reefs that are already
stressed by pollution and over-fishing have a harder time rebounding from
natural occurrences such as hurricanes and cyclones.
The future of coral reefs depends on how well humans
reduce the pressures of over-fishing and pollution while minimizing the already
catastrophic impact of ocean warming on coral reefs. The authors of a second
Science study note that some coral species are showing far greater tolerance to
climate change than others.
DECLINING STANDARDS FOR CORAL REEFS
“People pay hundreds of dollars to dive in reefs
so damaged that seeing them would make me cry,” said Jeremy Jackson, an author
on the two Science papers described in this story.
“They have no idea what they are missing or what
drastic deterioration has occurred,” said Jackson, a marine biologist from
Scripps Institution of Oceanography in La Jolla, CA and the Smithsonian
Tropical Research Institute in Balboa, Republic of Panama.
The ecosystem histories the marine biologists just
published are, in some ways, the equivalent to a person’s medical records,
according to Jackson. He noted that people often try to address the problems
facing coral reefs today without understanding the history of the problem.
“Doctors would be sued for malpractice if they
diagnosed patients the way many scientists are diagnosing oceans,” said
Jackson, referring to the practice of trying to solve ocean problems using
current data alone.
PROTECT NOW, SNORKEL LATER
“If we can get something in place in the next
ten years, we can bring many of these fish stocks back. Fish stocks have a
great capacity for resiliency. All is not lost,” said Pandolfi.
Pandolfi is not calling for the restoration of all
the world’s reefs to their pristine, unaltered state, he said. Instead, he
hopes his data will call attention to the critical situation facing coral
reefs.
“We need massive coordination at every level from
grassroots movements to governments to international non-governmental
organizations,” said Pandolfi.
“For example, if the Honduran government bans
fishing in part of a reef, what is going to prevent Hondurans from crossing the
invisible border and fishing on the Nicaraguan side of the reef? There has to
be coordination so that a country that tries to implement a reef protection
plan is not placed at a disadvantage in relation to its neighbours,” Pandolfi
explained.
Pandolfi noted that the new timeline of coral reef
destruction helped the scientists formulate reef management recommendations.
Among the recommendations are reef preserves called
“no-take areas,” international coordination, and reef restoration.
These historical analyses provide a baseline that
doesn’t shift and it helps to put the current crises into perspective, said
Pandolfi.
“We are a fundamentally ahistorical culture. By
ignoring history we can not solve the problems that we think we understand by
looking at the present,” said Jackson.
© 2003 by the American Association for the Advancement
of Science
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Posted August 30, 2003