Status of Coral Reefs of the World 2000

Status of Coral Reefs of East and North Asia
high latitude islands, bringing larvae and juveniles of tropical species. The Oyashio cold
current from the north blocks the Kuroshio around the latitude of Tokyo, which corresponds
to the limits of coral growth in this region. The Kuroshio maintains warm water temperatures
above16 o C in winter around the southern half of the country, and warms the Ryukyu Islands
to a minimum of 20 o C. Corals are therefore found on the coast of Japan up to Tateyama,
near Tokyo Bay, at latitude 35 o N, even though the water temperature can drop as low as
12 o C in winter, however the maximum extent of true reef growth is around 30 o N.
There are three types of reefs in Japan: fringing; barrier; and one raised atoll (Daito Island).
There are mostly fringing reefs in the Nansei Islands area, whereas around the Ogasawara
Islands small fringing reefs predominate, called ‘apron reefs’. The total reef area in the
Nansei Islands is about 100,000ha, with 41% of these in the Yaeyama Islands, 29% around
Okinawa and nearby islands, and 19% in the Amami Islands. There are 460ha in the
Ogasawara Islands, just south of the mainland (Muko, Chichi and Haha Islands). There are
about 400 hard coral species, with the highest number at Yaeyama (Iriomote Island, Sekisei
Lagoon, and Shiraho of Ishigaki Island), and decreasing towards the north. The Yaeyama
Islands are particularly important because they have high species diversity, with many rare
or endemic species (e.g. Leptoseris amitoriensis), and serve as ‘stepping stones’ for coral
larval dispersal from the Philippines to the Ryukyu Islands, and then further north.
Taiwan
There are extensive fringing reefs and some platform reefs around the main island and some
of the smaller islands. The species diversity is relatively high, with about 300 hard coral
species, 70 soft coral and gorgonian species, and 1200 fish species. The reefs are under the
impact of typhoons and have not been invaded by the crown-of-thorns starfish.
STATUS OF CORAL REEF BENTHOS
China
Hainan Province is the main coral reef region of China, however, little is known of the recent
status of coral reefs of the province, except for Sanya in the southeast where there are most
of the fringing reefs. Surveys of the reefs inside the Ya Long Wan Marine Park show that the
corals are in a healthy condition, but outside the park they have been badly damaged by
sedimentation, dynamite and poison fishing. In all locations, most edible reef organisms
occur in very low numbers indicating serious over-fishing and harvesting. These reefs occur
within the tropical and equatorial monsoon belt, characterised by high temperatures, high
rainfall, monsoon currents and waves, distinct dry and wet seasons, and occasional tropical
cyclones. The reef corals share close similarities with the islands and coastlines of the South
China Sea, and through them to the centres of reef coral diversity to the south in the
Philippines and Indonesia.
Japan
An aerial survey by the Environment Agency of Japan (EAJ) from 1990-1992 revealed that in
approximately 34,200ha of coral communities in the Nansei Islands, there was generally low
coral cover as follows: 61.3% of communities with coral cover less than 5%; 30.6% of
communities with coral cover between 5% and 50%; 8.2% of communities with coral
cover over 50%. In the moats (shallow lagoons) of the Okinawa main islands, 90.8% of the
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