|
The Tropical Indo-Pacific is the largest of all the
earthdive eco-regions and home to many of the
world's important coral reef systems. It embraces
large tranches of the tropical waters of the Indian
and Pacific Oceans, including the popular diving
location of the Red Sea.
The countries, island states, islands and other
dependencies that comprise this vast eco-region include,
in alphabetical order: American Samoa, Ashmore
and Cartier Islands, Australia; Northern
Territory, Queensland and Western Australia (North
of Geraldton), Bahrain, Baker Island, Bangladesh,
Bassas da India, British Indian Ocean Territory, Brunei
Darussalam, Burma, Cambodia, China (South China
Sea), Christmas Island, Cocos (Keeling) Islands,
Comoros, Cook Islands, Djibouti, East Timor, Easter
Island, Egypt (Red Sea Coast), Eritrea, Europa
Island, Fiji, French Polynesia, Glorioso Islands,
Guam, Hawaii, Howland Island, India, Indonesia, Iran
(Persian Gulf), Israel (Red Sea Coast),
Jarvis Island, Johnston Atoll, Juan de Nova Island,
Kenya (Indian Ocean Coast), Kingman reef, Kiribati,
Kuwait, Madagascar, Malaysia, Maldives, Marquesas,
Marshall Islands, Mauritius, Mayotte, Micronesia,
Midway, Mozambique, Nauru, New Caledonia, Niue, Northern
Mariana Islands, Oman, Pakistan, Palau, Palmyra Atoll,
Papua New Guinea, Paracel Islands, Philippines, Pitcairn,
Qatar, Reunion, Samoa, Saudi Arabia, Seychelles, Singapore,
Solomon Islands, Somalia, Spratly Islands, Sri Lanka,
Sudan, Tanzania (Indian Ocean Coast), Thailand,
Tokelau, Tonga, Tromelin Island, Tuvalu, United Arab
Emirates, Vanuatu, Viet Nam, Wake Island, Wallis and
Futuna Islands and the Yemen.
In an eco-region as large as the tropical Indo-Pacific
region, you would expect a diverse range of habitats,
and indeed there are many. River delta marshland and
mangrove ecosystems are important in the health and
diversity of our oceans.
The Rufiji River and the Tana River deltas of
East Africa host a mangrove ecosystem that is
vital to the maintenance of nearby reef and fish populations.
The vast complex of shallow freshwater lakes, marshes,
and seasonally inundated plains between the Tigris
and Euphrates rivers are among the most important
wintering areas for migratory birds in Eurasia, but
large scale drainage work, plus the not inconsiderable
effects of the Iran-Iraq war of 1980-1988 have taken
their toll on the delicate environmental balance.
The Mekong River Delta Mangroves of Vietnam and
Cambodia were nearly destroyed during the Vietnam
War by napalm and defoliants like Agent Orange. Conservation
and restoration efforts have led to successful re-establishment
of thousands of hectares, which now supply fuel wood,
fish, and prawns, and many birds have returned. Within
the Mekong Delta, there are 260 species of fish, 35
reptiles (including the endangered river terrapin),
6 amphibians, and 23 mammals, as well as numerous
birds.
The Sundarbans is a vast complex of intertidal
and estuarine areas situated on the border of India
and Bangladesh where the Ganges, Brahmaputra, and
Mehgna rivers converge in the Bengal Basin. The Sundarbans,
the most extensive area of mangrove in continental
Asia, provides nursery grounds for many species of
fish and invertebrates, including exploited species
such as tiger prawns. The productivity of the Sundarbans
plays a major role in supporting fisheries along the
east coast of India. Species found in and around the
mangroves include marine turtles, dolphins, estuarine
crocodiles, and seabirds.
The Rann of Kutch is a large inlet of the
Arabian Sea, criss-crossed with mangrove-lined creeks.
There is a complex of fringing coral reefs backed
by mud and tidal flats, coastal marsh, and mangrove
forest. The area also supports numerous sponges, mollusks,
fish, algae, seabirds, and marine mammals. It is,
however, the coral reef and associated marine ecosystems
that are arguably the most important the health of
our oceans. They are certainly one of the planet¹s
greatest natural attractions, and in the face of the
abundance and diversity of flora and fauna in the
reef environment, even the mighty rain forests pale
by comparison.
As mentioned above, the Rufiji Delta is one
of the most important coastal wetlands in East Africa.
Elsewhere along the coastline of Tanzania and Kenya,
coral reefs form an almost continuous fringing reef.
On Mafia and other islands, patch reefs predominate
on the western sides and well-developed fringing reefs
on the eastern sides, which may be among the finest
remaining reefs in the area. The reefs around Mafia
support 350 species of fish and 40 genera of corals.
The Basaruto Archipelago supports a diverse
range of marine habitats, including deep-sea areas,
coral reefs, rocky intertidal areas, sandy beaches,
tidal sand flats, seagrass meadows, and mangrove communities.
The barrier reefs of southwest Madagascar
are the most extensive in the Indian Ocean and among
the largest in the world, with about 200 km. of true
barrier reef (including the 18-24 km-long Gran Recífe
de Toliara) and a number of offshore coral islands.
Madagascar has high coral species diversity, with
over 60 coral genera. The Toliara reefs have high
fish diversity, with over 550 species, and supports
an important artisanal fishery. Several endemic marine
species occur here. The region also contains mangrove
and extensive seagrass beds
The Red Sea is the warmest and most saline
of the world's seas. No permanent coastal rivers or
streams flow into it, and it is partially isolated
from the open ocean. All of these features contribute
to the presence of unique flora and fauna. The diverse
and spectacular coral reefs for which the Red Sea
is renowned are found only in the central and northern
portions, where the reefs are well developed and drop
steeply into deep water. Considerable disturbance
occurs to many Red Sea reefs, as a result of abnormally
high numbers of sea urchins, due to decline in the
population density of their predators. In addition,
spearfishing, souvenir collecting, scuba diving and
the use of the coast for recreational activities represent
an important disturbance and stressing of the reef
systems. Oil exploration and transport (several oil
spills from tankers occurred in the area) have given
rise to increansingly severe pollution. Sewage discharge,
chemical pollution and sedimentation from urban development
pose further threats to the Red Sea's coral reefs.
Species of particular interest in the area are the
green turtle (Chelonia mydas), loggerhead turtle
(Caretta caretta), leatherback turtle (Eretmochelys
imbricata), dugong (Dugong dugong), white-tip
reef sharks (Triaenodon obesus), butterfly
fish (Chaetodon spp.), giant clams (Tridacna
spp) and different species of dolphins (Delphinidae).
The Arabian Sea and Persian Gulf contain rare,
high-latitude coral reefs and green turtle-nesting
beaches. The shallow waters of Kuwait Bay are a critical
nursery habitat for commercial species of shrimp and
fish and contain a unique species of mudskipper. Dugongs
are both actively hunted and caught by accident.
The Maldives, the Chagos Archipelago,
and Lakshadweep are composed entirely of atolls,
with reefs and sandy islands, and form the Laccadive-Chagos
chain that extends southward from India to the Central
Indian Ocean. The Maldives contains extensive and
largely intact reefs, and comprise perhaps one of
the world's most complex reef systems.
The Chagos Archipelago has the largest expanse of
undisturbed reefs in the Indian Ocean, as well as
some of the most diverse. In addition to five atolls,
including Great Chagos Bank, the world's largest atoll
in terms of area, there are two areas of raised reef
and several large submerged reefs. The Chagos reefs
are of particular interest for the presence of an
endemic coral, Ctenella chagius. The Chagos
Archipelago forms the British Indian Ocean Territories
and have been inhabited since the late 18th Century.
However, the islanders suffered a forced evacuation
in the 1970's when the US-UK military base in Diego
Garcia was established. There are strict environmental
controls in place, and diving or snorkeling is forbidden
in the area.
The Chagos Archipelago has the largest expanse
of undisturbed reefs in the Indian Ocean, as well
as some of the most diverse. In addition to five atolls,
including Great Chagos Bank, the world's largest atoll
in terms of area, there are two areas of raised reef
and several large submerged reefs. The Chagos reefs
are of particular interest for the presence of an
endemic coral, Ctenella chagius.
The Maldives and Chagos islands are important
nesting sites for green turtles (Chelonia mydas),
and many of the islands in the chain have seabird
nesting colonies. The greatest threats to the reefs
come from the relatively rapid establishment and growth
of the tourist industry and the introduction of mechanized
fishing. The natural vegetation is often cleared to
make the islands "more attractive". On several islands
the organic litter is burned and is lost to the island
ecosystem. Coral mining has caused significant damage
to the reefs. The construction of groynes, breakwaters
and jetties has caused locally severe disturbance
to some fringing reefs.
Unlike the Laccadive-Chagos chain, the Andaman
and Nicobar Islands in the Bay of Bengal are high
volcanic islands, arising from a submerged mountain
chain that follows a southward extension of the continental
shelf. The Andaman and Nicobars have fringing reefs
around many islands, and a 320 km- long barrier reef
on the west coast. While poorly known scientifically,
these reefs may prove to be the most diverse and best
preserved in India.
The Isthmus of Kra extends south off mainland
Southeast Asia, forming a boundary between the Indian
and Pacific Oceans and linking Thailand to Peninsular
Malaysia. This ecoregion includes some of the best-developed
reefs in Thailand, on the west side of the isthmus,
and globally important reefs belonging to Malaysia,
on the eastern side.
The Sulawesi Sea of the Philippines, Indonesia
and Malaysia is one of the most diverse marine
communities on earth. The abundant coral reefs, mangroves,
and seagrass beds of the Lesser Sundas support the
richest array of coral reef animals and plants in
the world. The reefs of the Sulu Sea, however, have
been severely degraded, yet remains the most diverse
coral ecosystem on earth, with over 450 species of
scleractinian (hard) corals, compared with 50 in the
Caribbean and around 200 in the whole of the western
Indian Ocean.
The diverse and complex coral reefs and marine ecosystems
of Papua New Guinea and the Moluccas support
numerous endemic species of coral, fish and invertebrates,
as well as populations of marine turtles, dugongs,
and giant clams. Coral reefs extend for over 3,000
km along the western coast of Australia, with numerous
reef systems. A wide variety of reefs are found, ranging
from open ocean atolls to fringing and barrier reefs.
The reefs contain a great diversity of fish, corals,
and other invertebrates. Ten percent of the world¹s
dugong population occurs at Shark Bay in this region.
The Great Barrier Reef along the northeastern
coast of Australia is the largest single reef system
in the world, extending 2,000 km. from the low-latitude
tropics to temperate zones. It provides habitat for
a great many forms of marine life. There are an estimated
1500 species of fish and about 350 species of hard-reef-building
corals; more than 4000 mollusc species and over 400
species of sponge have been collected. It is the most
diverse in reef types, habitats, and environmental
regimes, making this an area of enormous scientific
importance. The northern tropical waters are highly
diverse, though there are relatively few endemics
species. The temperate portions of the reef, in contrast,
have low overall species diversity but a higher proportion
of endemic species Outbreaks of crown-of-thorns starfish
(Acanthaster planci) occur, destroying a high
proportion of hard coral cover.
Palau is considered to have some of the richest
and most diverse coral reefs in the Pacific, with
300 species of coral. Micronesia's reefs also
support diverse communities of coral, fish, and marine
mammals. Species to be found here include all of the
seven known species of giant clam (Tridacnidae
spp.), hawksbill (Eretmochelys imbricata)
and green turtle (Chelonia mydas).
The South Pacific Marine Ecosystems include Vanuatu,
Fiji, New Caledonia, Samoa, Tonga, and Tuvalu
and contain many internationally and regionally important
sites for marine biodiversity, particularly coral
reefs and mangroves. There are numerous lagoons, barrier
and fringe reefs, and eelgrass beds.
The Eastern Polynesian Island Marine Ecosystems
include Hawaii, the Marquesas, Easter Island, Societies
and Tuamotus. These isolated oceanic islands are
at a greater distance from a continent than any other
islands in the world. The Marquesas, along with Hawaii
and Easter Island, have the highest levels of marine
endemism of any island or island group in the Pacific.
On the major islands, land run-off and sedimentation
have limited reef development in many areas. Urbanization
and associated anthropogenic impacts pose serious
challenges to water quality. With the increase in
fishing technology and demand, overfishing is a persistent
problem on the high islands. Outbreaks of crown-of-thorns
starfish (Acanthaster planci) have been reported
for several areas.
|