- "The coral reefs are the canary
in the mine for global warming. They will go first," said Dr. Thomas
Goreau in testimony at a meeting at the climate change talks in Buenos
Aires.
-
- Goreau, a scientist working with the
International Union for the Conservation of Nature, said a significant
proportion of the world's coral has died this year as a result of the highest
sea temperatures on record. In areas surveyed in the Indian Ocean, between
70 and 90 percent is dead, IUCN scientists said.
-
- Reefs in tourist areas renowned for their
diving opportunities, such as the Seychelles, Mauritius and the Maldives,
have suffered massive die-offs. Thousands of miles of corals in the western
Pacific, from Vietnam to the Philippines and Indonesia, have died or bleached
as they have been starved of the symbiotic algae that provide their food
and energy. The only large areas of coral to have escaped some devastation
are the atolls of the central Pacific.
-
- To highlight the economic importance
of coral reefs, Gourequ noted that reefs provide more than 100 countries
with fish and other services, such as tourism worth $500 billion a year.
They also prevent tidal waves and erosion. And they support 93,000 fish
species -- 25 percent of the total -- in 0.3 percent of its sea area.
-
- The IUCN conclusions seem to be backed
up by the results of Reef Check '97, the first global survey of human impacts
on the world's coral reefs. Organized by the Institute for Environment
and Sustainable Development, the survey involved more than 100 marine scientists
and 750 recreational divers who surveyed 300 coral reefs in 30 countries
and territories between June 15 and Aug. 31, 1997.
-
- The Reef Check methods differ from those
used in traditional ecological surveys in that they were focused specifically
on detecting the effects of humans on the coral reef ecosystem. Results
from about 230 sites revealed a clear pattern of global damage to coral
reefs, particularly due to overfishing and destructive fishing.
-
- Reef Check '97 teams found that the mean
percentage of living coral cover on reefs was 31 percent globally, with
the Caribbean recording the lowest value at 22 percent, possibly reflecting
recent losses due to bleaching and diseases. The ratio of live to dead
coral was highest in the Red Sea, suggesting that these reef corals are
the healthiest in the world. One apparent bit of good news is that only
seven sites showed greater than 10 percent cover of fleshy algae, indicating
that nutrient enrichment associated with sewage pollution was not a problem
at most of these "good" sites. Sewage pollution may be more important
at reefs near urban areas which were not extensively studied in this survey.
-
- Reef fish in the Indo-Pacific, seem to
be hit hard. The humphead wrasse and barramundi cod were once moderately
abundant on reefs, but none were reported at 85 percent of 179 reefs surveyed.
Of more than 25 kilometers of Indo-Pacific reef surveyed in detail, only
26 humphead wrasse were seen. At the 125 Asian and Australian reefs surveyed,
only five barramundi cod were recorded. These results suggest that cyanide
and other forms of fishing have severely damaged populations of these once
moderately abundant species.
-
- High-value, edible sea cucumbers used
to litter the seabed around many reefs. The three species included in Reef
Check were totally absent from 41 percent of Indo-Pacific reefs surveyed,
demonstrating the extent of over-harvesting. An average of 17 giant clams
was found on the Indo-Pacific reefs. An indication of what natural populations
used to be like was provided by the 150 to 250 giant clams recorded at
several protected sites in the Red Sea and Australia.
-
- Hong Kong provides an example of coral
reefs subjected to almost every form of disturbance: overfishing, poison
and dynamite fishing, pollution and sedimentation. Out of 11 collectible
or edible indicator species only two (Trochus shells and butterflyfish)
were recorded. Several of these once-abundant species are now effectively
extinct in Hong Kong. The. Sarawak Reef Check team reported that 99 percent
of the reefs have been damaged by blast fishing.
-
- Surveys were also conducted in 1998,
and the results are still being tallied. Reef Check works well as a rapid
assessment tool, and indicates where additional, more detailed scientific
studies are needed. It also shows the promise that can be found in the
areas that have been formally protected and are showing signs of regeneration.
-
- A joint statement was issued by IUCN's
reef scientists at the Buenos Aries conference. It said: "Unless this
conference takes effective action to stop global climate change, coral
reefs and the benefits they provide will be condemned to death. Other ecosystems
will follow."
|
