352
WORLD ATLAS OF CORAL REEFS
Pagan is one of the larger northern islands, with one
active volcano, but there are reports of some limited coral
and reef development along parts of its coastline. Maug,
which is actually a complex of three islands encircling a
submerged volcanic crater, has been dormant for some
time and there is reported to be some active coral growth.
Sarigan, Anatahan and Alamagan are volcanic islands
which, though inactive for some time, are believed to have
only limited coral or reef development. In addition to
these islands there is considerable volcanic activity below
the sea and a number of volcanically active banks are
known, including Zealandia Banks (between Guguan and
Sarigan) and Esmeralda Bank (west of Tinian). Eruptions
do occur in these areas, and it is likely that many more go
unrecorded. Supply Reef, near Maug, is an inactive
submerged crater reported to have some living coral
communities on the crater rim.
The Mariana Islands, lying relatively close to the
center of coral reef biodiversity in the Philippines and
Indonesia, enjoy high diversity. Guam, which is fairly well
studied, has about 300 recorded species of scleractinian
corals. 950 species of reef fish, 220 species of benthic
algae and more than I 400 species of molluscs. Live coral
cover in Guam reaches 50 percent in some areas, but
the majority of sites now show less than 25 percent. Both
diversity and cover decrease considerably in the geologically younger northern islands where the volcanic
conditions are unfavorable for many species, while in
Northern M ariianas
General Data
Population [thousands]
72
GDP Imillion US$1
bbU
Land area Iknn^l
A59
Marine area (thousand km^l
1
823
Per capita fish consumpti on Ikg/yearl
na
Status and Threats
Reefs at risk 1%)
na
Recorded coral diseases
2
Biodiversity
Reef area Ikm^l
<50
Coral diversity
na / na
Mangrove area Ikm'l
7
No. of mangrove species
1
No. of seagrass species
3
Guam
General Data
Population (thousands)
155
GDP (million US$1
3 066
Land area (km?)
572
Marine area (thousand km^)
218
Per capita fish consumption (kg/year)
na
Status and Threats
Reefs at risk (%)
100
Recorded coral diseases
1
Biodiversity
Reef area (km?)
220
Coral diversity
UO/220
Mangrove area (km?)
1
No. of mangrove species
10
No. of seagrass species
na
Left; The eastern triangle butterflyfish Chaetodon baronessa feeds exclusively on Acropora polyps^ Right: A group of
batfish Platax orbicularis against a bare volcanic rock.
WORLD ATLAS OF CORAL REEFS
Pagan is one of the larger northern islands, with one
active volcano, but there are reports of some limited coral
and reef development along parts of its coastline. Maug,
which is actually a complex of three islands encircling a
submerged volcanic crater, has been dormant for some
time and there is reported to be some active coral growth.
Sarigan, Anatahan and Alamagan are volcanic islands
which, though inactive for some time, are believed to have
only limited coral or reef development. In addition to
these islands there is considerable volcanic activity below
the sea and a number of volcanically active banks are
known, including Zealandia Banks (between Guguan and
Sarigan) and Esmeralda Bank (west of Tinian). Eruptions
do occur in these areas, and it is likely that many more go
unrecorded. Supply Reef, near Maug, is an inactive
submerged crater reported to have some living coral
communities on the crater rim.
The Mariana Islands, lying relatively close to the
center of coral reef biodiversity in the Philippines and
Indonesia, enjoy high diversity. Guam, which is fairly well
studied, has about 300 recorded species of scleractinian
corals. 950 species of reef fish, 220 species of benthic
algae and more than I 400 species of molluscs. Live coral
cover in Guam reaches 50 percent in some areas, but
the majority of sites now show less than 25 percent. Both
diversity and cover decrease considerably in the geologically younger northern islands where the volcanic
conditions are unfavorable for many species, while in
Northern M ariianas
General Data
Population [thousands]
72
GDP Imillion US$1
bbU
Land area Iknn^l
A59
Marine area (thousand km^l
1
823
Per capita fish consumpti on Ikg/yearl
na
Status and Threats
Reefs at risk 1%)
na
Recorded coral diseases
2
Biodiversity
Reef area Ikm^l
<50
Coral diversity
na / na
Mangrove area Ikm'l
7
No. of mangrove species
1
No. of seagrass species
3
Guam
General Data
Population (thousands)
155
GDP (million US$1
3 066
Land area (km?)
572
Marine area (thousand km^)
218
Per capita fish consumption (kg/year)
na
Status and Threats
Reefs at risk (%)
100
Recorded coral diseases
1
Biodiversity
Reef area (km?)
220
Coral diversity
UO/220
Mangrove area (km?)
1
No. of mangrove species
10
No. of seagrass species
na
Left; The eastern triangle butterflyfish Chaetodon baronessa feeds exclusively on Acropora polyps^ Right: A group of
batfish Platax orbicularis against a bare volcanic rock.