#Status of Coral Reefs 2002 - International Coral Reef Action Network

Status of Coral Reefs of the World: 2002
Vietnam
The 1998 bleaching event resulted in bleaching of 37% of the coral colonies in the Con
Dao islands. This was additional to the 10% of corals killed previously. The soft coral,
Sinularia and fire coral, Millepora were most affected with almost 100% and 83% of
colonies bleached respectively. Hard corals that were most affected included Porites
(57%), Symphyllia (42%), Leptastrea (40%), and Acropora (19%, many newly killed).
Bleaching also caused decreased fish diversity especially among butterflyfishes,
illustrating the relationship between reef fish and coral health. Surveys from 1998 to 2001
have indicated a slow recovery. In many places, coral bleaching exacerbated
anthropogenic stresses and have resulted in continued reef decline since the El Niño
event. Continued coral loss from sedimentation is evident in Ha Long Bay and the Cat Ba
Islands. However, reefs of Binh Thuan and Ninh Thuan provinces, which are near an
upwelling, recovered well. Recovery from bleaching was slow in the Con Dao islands, but
restoration of fish density was better than elsewhere based on monitoring data from 1999
to 2001.
ANTHROPOGENIC THREATS TO CORAL REEF BIODIVERSITY
Indonesia
Human impacts, direct and indirect, are the greater threat than natural impacts. The
major causes of coral reef degradation in Indonesia are blast and cyanide fishing,
increased sedimentation, and sewage and industrial pollution. The majority of the human
population is concentrated in the coastal area. Rapid economic development, particularly
around major population centres results in large amounts of sewage and industrial
pollution, causing the decline of many reef areas especially those near growing cities such
as Jakarta, Ambon and Ujung Pandang. Two coral species of the Genus Montipora used to
occur in Jakarta Bay, but not any more. Average live coral cover in Jakarta Bay is 2.5% and
in Ambon Bay, 24.0%. Muro ami fishing (driving fish into set nets by bashing the corals)
and blast fishing are considered the major factors contributing to physical damage of
reefs. These fishing techniques break corals and damage the bottom habitat. At least two
groups of fishers engage in blast fishing. Small-scale fishers use self-made bombs from
fertiliser to blast small areas in shallow reefs near their homes. There are however,
medium to large-scale fishers using stronger blast devices with detonators. They fish in
remote areas (about 7 to 10-day trips), destroying vast areas of reef, from the reef slope to
about 20m depth. They also use compressors to supply air to divers sent down to collect
the fish. The demand for reef dwelling grouper and humphead (Napolean) wrasse has risen
dramatically over the past few years and Indonesia is now the largest supplier of live reef
food-fish to the Asian market. It is estimated that more than 50% of the total wild-caught
live reef fish are currently supplied to Hong Kong and Singapore. Cyanide is a broadspectrum
poison causing damage to the liver, intestine and reproductive organs of the fish
and also causing extensive damage to corals. Blast and cyanide fishing have caused
irreversible damage to many Indonesian reefs. These destructive fishing techniques
continue throughout Indonesia. Some of the traditional fishing methods may have also
contributed to the degradation of marine resources. It becomes imperative therefore to
introduce new, more environmental-friendly fishing techniques as part of the
management of a sustainable coastal fishery. Lift net fishing ‘Rompong’ and hand line
fishing are currently considered non-threatening to demersal and sedentary marine
134