The western end of the Indonesian islands includes Sumatra and Java which, with Kalimantan, are located on the Sunda Shelf, a vast continental shelf extending across a considerable part of the South China Sea. Both are continental islands, but with the boundary between the Indian and Eurasian tectonic plates lying off their southwestern and southern boundaries, there are numerous volcanoes. The continental shelf lies relatively close to the shore on the western side of Sumatra and south of Java. Some distance off the west coast of Sumatra and off the continental shelf, lies the long chain of the Mentawai Islands. Off the east coast of Sumatra there is a complex of smaller islands at the southern end of the Strait of Malacca, the Riau Archipelago. Further south, towards the Java Sea, Bangka Island lies just off the Sumatra coastline and Belitung Island lies midway between Sumatra and Kalimantan. There are a few small islands north of Java, while Bali lies immediately to the east. Bali, unlike the other islands which continue in a chain to the east, is still located on the Sunda Shelf. The western side of Sumatra is heavily mountainous, with only a narrow coastal plain. In contrast the eastern side is low-lying and there is considerable riverine input all along this coastline. Java is very mountainous in its entirety, although the coastal plain is a little wider to the north and it is here that the most considerable riverine runoff occurs: rates of coastal progradation in the Solo Delta have been measured at 70 meters per year. The coastal waters of both eastern Sumatra and northern Java are generally quite turbid.

Weather and water conditions are largely determined by the opposing monsoon systems. During the Northeast Monsoon (December-March) winds over Sumatra predominate from the northeast, bearing moist air and typically driving higher rainfalls. This air is deflected in southern Sumatra and out over the Indian Ocean and bears round such that Java is dominated by northwesterly and westerly winds. During the Southeast Monsoon (particularly June-July), typically drier air flows from the southwest across Sumatra, and from the southeast across Java. Patterns of surface water currents are largely driven by these winds and during the Northeast Monsoon currents from the northeast flow in and are largely deflected into southeast and eastward flowing currents along southern Sumatra and Java. These are mirrored by longshore currents flowing south and east along the Indian Ocean shores of these islands. During the Southeast Monsoon some of these patterns are reversed, with strong westward flowing currents along the coasts of Java and deflecting northwards along the east coast of Sumatra. The west coast of Sumatra, by contrast, maintains a southeasterly flowing current all year round. In the Strait of Malacca there is a permanent current flowing to the northwest.

Surprisingly little is known about the development of reefs around Sumatra. Fringing reefs are considered well developed in the north around Aceh and around the islands immediately north of Sumatra. They are are also likely to be widespread along much of the west coast of Sumatra facing the Indian Ocean – and have actually been recorded at the Mentawai Islands – but there is little published material describing the remainder of this coastline. Likewise this region is believed to support some extensive barrier reef systems: an 85 kilometer section is reported in the north, 20 kilometers off the coast of Aceh. This is a submerged or drowned system some 13-20 meters below the surface, but it is not clear to what degree it enjoys active coral growth. Further barrier reefs along the west coast of Sumatra are recorded with a combined length of 660 kilometers, although these have been little studied and rarely mentioned in regional reviews. Reefs are thought to be poorly developed along the east Sumatra coast where there is significant riverine input and the coastline is dominated by large mangrove communities. Fringing reefs are widespread in the Riau Archipelago and 95 species of scleractinian coral have been recorded from Batam Island. Water conditions are highly turbid in this area, however, and coral cover quickly diminishes with depth. Much further south around Belitung Island, fringing reefs have significantly higher diversities, presumably associated with more suitable conditions for reef development – 174 scleractinian species have been recorded.

The fringing reefs around Java have received little attention despite their high accessibility (compared to much of the rest of the country). There are well developed fringing reefs surrounding the volcanic islands in the Sunda Strait. Although not marked on most charts, it has been suggested that there may be extensive reef development off the south coast of Java, but that classic reef flat and reef crest structures have not developed due to the extreme exposure and high energy environment. Fringing reefs are well developed around the Blambangan Peninsula and off the short east coast of Java, with reef flats reaching 200-400 meters in width, but these are again limited off much of the north coast. One of the best known reef complexes in the region is the Kepulauan Seribu patch reef chain, also known as the Thousand Islands. This is a group of almost 700 reefs lying in a chain just northwest of Jakarta Bay. Many have associated islands and most have shallow intertidal reef flats. The reef slopes are quite diverse and there appears to be an increase in diversity with distance from Java – 88 scleractinian species have been recorded at one of the southerly reefs, rising to 190 species in the north. Outbreaks of crown-ofthorns starfish in 1995 may have reduced diversity in these southern islands still further.

Reefs are widely developed around the Karimunjawa Archipelago north of Java, and there are reported to be extensive fringing communities around Bawean Island on its eastern side. Fringing reefs are also well developed along the south coast of Bali and have a deep spur and groove formation associated with the high exposure along this coast. The 1998 bleaching event did affect the reefs around Bali, with over 75 percent bleaching in some areas. North of Java it appeared to be more varied and generally less significant.

Much of the coastline of Kalimantan, or Indonesian Borneo, is low-lying and subjected to considerable riverine inputs. The Mahakam River, in particular, is noted for its high volume discharge and has been estimated to produce 4-10 million tons of sediment annually, with a plume which may extend up to 400 kilometers southeast of the Mahakam Delta. Even between the river mouths, the shores are largely fringed by mudflats and there are extensive mangrove communities. The main island lies on the Sunda Shelf and hence is surrounded by extensive shallow, and often relatively turbid, waters. To the east, however, the continental shelf edge lies relatively close to the mainland. There are several nearshore islands and some much further offshore, notably the Anambas, Natuna and Tambelan Archipelagos on the border between the South China Sea and the Natuna Sea. The patterns of monsoon weather are similar to those described for Sumatra and Java, with Northeast Monsoons bringing a northeasterly airflow which is deflected around the south of Kalimantan such that the south coast actually receives a predominantly westerly flow. Surface water currents at this time mirror these winds. During the Southeast Monsoon airflows are predominantly from the southwest, however the surface water currents are a little different, flowing from the north along the east coast, then deflecting towards the west as they meet the south coast.

Fringing reefs are absent from much of the main Kalimantan coastline, but do occur away from major areas of riverine input. They are thought to be well developed on the offshore continental islands, and also off the large headlands such as Tanjung (headland) Datu and T. Blimbing in the west, and T. Sambar, T. Putih, T. Pengujan and T. Selatan in the south. In the east, extensive reefs are recorded for 140 kilometers between T. Setan and T. Pamerikan, and again around the Mangkalihat Peninsula, while there is also an extensive fringing reef to the north of the Berau Delta. Offshore from the east coast lies Indonesia’s longest continuous barrier reef system, the Sunda Barrier Reef, some 630 kilometers long, on the edge of the Sunda Shelf. Despite its size and potential economic, social and biological importance, this reef is largely undescribed. The coral communities of the Anambas, Natuna and Tambelan Archipelagos have not been well studied, although well developed fringing reef communities have been recorded on charts of the area.

This region is sometimes referred to as Wallacea, and encompasses the islands of Sulawesi and the Nusa Tenggara Islands. It is an area of complex oceanography: all of the islands have narrow continental shelves and many are separated from one another by relatively deep waters. The geological history of this region is extremely complex, and there are active volcanoes all along the southern islands and in the northeast peninsula of Sulawesi. All of these islands are mountainous, but their relatively narrow widths mean that there are few major watersheds and riverine input is widely dispersed. Air circulation patterns generally follow those of Kalimantan: during the Northeast Monsoon northerly winds reach the north of Sulawesi, but are rapidly deflected, becoming westerly along the southern coast of Sulawesi and the Nusa Tenggara Islands, while this pattern is almost exactly reversed during the Southeast Monsoon. Surface currents flow permanently eastwards along the north coast of Sulawesi and permanently southwards along the west coast. Between Sulawesi and the Nusa Tenggara there is a strong east flowing current during the Northeast Monsoon, which is reversed during the Southeast Monsoon. South of Nusa Tenggara in the Timor Sea the currents flow permanently westwards.

Conditions in this region are ideal for reef development and there are extensive fringing reefs along the shores of most islands, including some near continuous stretches running for hundreds of kilometers along the coastline of Sulawesi. These are particularly well developed along the eastern arm of Sulawesi where reef flats are typically 100-200 meters wide. In other areas reef flats may be less than 20 meters wide, resulting in their omission from many marine charts. Further offshore a large number of barrier reef systems have been described with a total length of 2 084 kilometers. Among the best known is the Spermonde Barrier Reef, which has a series of reefs leading towards the outer edge in a manner similar to the Great Barrier Reef – some 224 scleractinian corals have been described in this system. South of Peleng Island on the Banggai Platform there is another shelf edge barrier reef system, the Banggai Barrier Reef. This is of particular interest because of the development of faros, circular atoll-like structures otherwise largely associated with the Maldives (Chapter 8). The Togian Islands, located in the mouth of Tomini Bay in northern Sulawesi, lie in very deep water and boast a number of interesting reef formations including fringing, barrier and atoll reefs. The reefs of the Tomini Bay are some of the most biodiverse in the world, with an estimated 77 species of Acropora alone. The 1998 bleaching event appears to have had relatively little impact over much of this region, and little or no bleaching was recorded north and west of Sulawesi.

There is little detailed information describing the reef communities of the Nusa Tenggara Islands, but fringing reefs are again widespread. Studies of Lembata Island in the center of the group show significant variation around the coastline. The northwest fringing reef is well developed with a 200-400 meter wide reef flat rich in seagrasses; this reef flat is even wider on the west coast. By contrast, the south coast has a narrower reef flat, which is fully exposed to Indian Ocean swell and may be further affected by cool water upwellings – a pronounced spur and groove structure is again noted, and a number of deep water species are found which may prefer cooler waters. North of these islands well developed barrier reefs are reported to occur northwest of Sumbawa and north of Flores. At the southern end of the Makassar Strait and in the Flores Sea there are a number of atolls, including the largest in the country: Kalukalukuang, Sabalana and Taka Bone Rate, each over 60 kilometers in length with complex atoll rims formed from individual patch reef structures separated by narrow and deep channels. In the western end of the Banda Sea there are, additionally, many smaller atolls.

This final region, dominated by the coastline of Irian Jaya, also includes the complex island groups of the Moluccas to the west of Irian Jaya and a chain of small archipelagos along the south of the Banda Sea, stretching from Timor in the west to the Aru Islands in the east close to Irian Jaya. Overall this is another region of relatively complex bathymetry. Its waters are very deep, and even islands only a few tens of kilometers apart might be separated by depths of over 1 000 meters. The only areas of relatively extensive shallow water and true continental shelf are a platform west of the Bird’s Head (Doberai) Peninsula and the wide expanse of the Arafura Sea, south of Irian Jaya and east of the Aru Islands. The latter largely lies above 100 meters in depth and is quite turbid, in marked contrast to the clear oceanic waters of much of the rest of the region. The coastline of Irian Jaya remains very poorly described. Large areas are low-lying and there is considerable riverine input, particularly along the south coast. The Bird’s Head Peninsula is more mountainous.

During the Northeast Monsoon, northwesterly winds cut across most of the region, while during the Southeast Monsoon southeasterly winds come up towards southern Irian Jaya and the southern Moluccas, but these are deflected to become westerly in the more northern areas. Surface currents are somewhat mixed in this region. However, a northward current flows between Irian Jaya and Halmahera and an eastward current flows along the north shore of Irian Jaya during the Northeast Monsoon. This pattern reverses during the Southeast Monsoon.

Along the southeast coast of Irian Jaya wide areas are unsuitable for reef development: this coastline includes some of the largest mangrove forests in the world – those off the central coast and in Bintuni Bay may rival the area occupied by the Sundarbans forest between India and Bangladesh. There are reported to be fringing reefs along much of the higher coastal areas to the west. There is little or no information describing the reef communities around Bird’s Head Peninsula. Along the rest of the north coast there are fringing reefs on all islands in Cendrawasih Bay, however the central and eastern coasts of this bay are dominated by mangrove forests and wide mudflats, and fringing reef systems have not developed. Further east, fringing reefs are believed to follow a large proportion of the coastline between Sarmi and the border with Papua New Guinea. For the most part these are poorly described, but reef flats are estimated to reach 300-400 meters wide in places. Further offshore, north of Irian Jaya, and also east of Halmahera, there are several small atolls. Off the east coast of the Aru islands there are vast fringing reefs, with shallow reef flats extending up to 15 kilometers from the coast. Corals are also widespread in the narrow winding channels which separate these islands, despite the still and often turbid waters which are found here. Fringing reefs are also found on the west coast of these islands, particularly in the northwest.

Indonesia is the largest archipelagic nation in the world comprising an estimated 17,508 islands. Coastal length has been variously estimated at between 80,791km (Moosa, 1994) and 204,000km (Tomascik et al, 1997). The official estimate for the area of coral reefs is 7500km² (KLH 1992). A re-estimate by Tomascik et al (1997) based on the longer figure for coastline length is 85,707km² which represents about 14% of the world total.

The area covered by this review is loosely termed as Eastern Indonesia. It includes the eastern shores of the island of Kalimantan, Sulawesi, Halmahera, The Moluccas, West Papua and the islands of Bali, Flores, Sawu, Timor and Banda Seas. It thus covers the provinces of Bali, West Papua, East and South Kalimantan, Maluku, West and East Nusa Tenggara and North, Central, South and South-east Sulawesi. This area probably contains more than 50% of Indonesian coral reefs. It also corresponds closely to the areas of East and Central Indonesia as defined by Tomascik et al (1997) and shown by reef type in table 1.1.

Indonesia straddles the equator and it is not surprising that it has such an area of coral reefs. As Tomascik et al (1997) note the “complex interplay of atmospheric, oceanographic and geologic processes has resulted in one of the most dynamic marine environments on the planet”. Although seasonal fluctuations do occur, variations in temperature and salinity are probably less than anywhere else in the world and disruptions from meteorological phenomena such as hurricanes are almost unknown. As disturbance is one factor which is responsible for the maintenance of high diversity and overall stability of coral reef ecosystems (Connell 1978), it is therefore somewhat enigmatic to find that Eastern Indonesia is the world centre of diversity for coral reefs and associated flora and fauna (Moosa, 1999).

A major influence on this diversity relates to the geological history of the region. The modern scleractinian corals evolved in the ancient Tethys Sea in the Trassic, (Veron, 1995). This body of water lay between the northern continents of Eurasia and the Southern African and Indo-Australian land masses. These have drifted together, closing the Tethys Sea from the west, the collision forming the massive fold mountains stretching from the Pyrennees and the Alps to the Himalayas. The main centre of coral reef evolution has thus been pushed eastwards to what is now archipelagic Southeast Asia. This region, centred on Indonesia is the direct descendant of the Tethys Sea and is a modern collision zone with all the same characteristics of complex archipelagoes and island chains in which earthquakes and volcanic action provide the required degree of disturbances for the high diversity.

Highly favourable biological, ecological and geological conditions of Eastern Indonesia have thus provided the richest and most diverse region of modern coral reefs. Unfortunately within Indonesia as a whole these are under increasing anthropogenic pressure from a population which is largely coastal and utilises coral reef resources extensively. Indonesia’s population is currently about 195 million, though the 11 provinces which make up Eastern Indonesia, as defined above, are home to a proportionally lower population of 35 million people. Many areas of reefs may still be in good condition and could benefit from sustainable management based on integrated coastal zone management principles.


This section describes the coral reefs of Eastern Indonesia from north and west to south and east. It relies extensively on the descriptions in Tomascik et al (1997).

A major influence on reef distribution in eastern Kalimantan is the Mahakam River which drains almost one third of East Kalimantan with a discharge of 1500m3/sec a suspended sediment load of 80mg/l and a sediment yield of up to 10 x 106 tonnes annually. The plume may extend 400km to the south-east of the Mahakam Delta and is responsible for a general paucity of coral reefs along the coastline to the south. Only occasional fringing reefs are found with some offshore patch reefs, for example in front of Balikpapan Bay.

Immediately to the north of the Mahakam, however, well developed fringing reefs are found from Tanjung (Cape) Setan to Tg. Samuntai (140km). A further 180km of fringing reefs are found around the Mangkalihat Peninsula but are then disrupted by the Berau River discharge. However, because of the southward coastal current, fringing reefs are again found immediately to the north for a further 60km to Tg. Karangitigau. Northwards to the border with Sabah the coastline is reefless, dominated by major river deltas.

The southwestern coast of South Kalimantan is also largely deltaic and devoid of reefs. Conditions for reef development improve considerably east and north of Tg. Selatan and significant fringing reef development occurs along the southeast and southwest coasts of the island of Pulau Laut.

Offshore in eastern Kalimantan, the better water quality has allowed the development of three barrier reef systems (Table 1.2) where substrate is suitable. The longest barrier reef in Indonesia runs inside the 200m isobath at the margin of the Sunda shelf. Lying 60km offshore, the Great Sunda Barrier Reef has a length of 630km but little work appears to have been carried out on this system. Smaller barrier reefs are found north of the Mahakam delta. The Berau system is found immediately north of the Berau Delta, in places only 10km offshore, and has a length of 25km. Parts of the Mangkalihat Peninsula are also bordered by a barrier reef. North of the Mangkalihat Peninsula are three major reefs which Tomascik et al (1997) term atolls, though they are more likely large lagoonal shelf reefs rather than fulfilling the strict geological criteria for oceanic atolls with volcanic foundations. These reefs lie about 90km offshore, in front of the Berau barrier reef (note their location as given in table 16.1 of Tomascik et al (1997) is in error). They are of considerable size: Muaras (288km²), Maratua (690km²) and Kakaban (21km²), the latter two having raised limestone rims up to 120m above sea level. Open water coral reefs are also probably associated with the islands of the Java Sea in the south (Pulau Keramian, P. Matasiri, P. Kadapongan, P. Kalamban).

The island of Sulawesi, with a coastline of 4750km, probably has the largest coral reef area in Indonesia. A very high proportion of its coastline is fringed with reefs, as are the offshore islands. Although a systematic geographic description is not available, most references to Sulawesi describe almost continuous fringing reefs up to 200m wide.

Even more impressive are the almost undescribed barrier reefs of Sulawesi. Tomascik et al (1997) describe 34 individual barrier reefs around the islands with a total length of 2084km, i.e. bordering 43% of Sulawesi’s coastline (Table 1.3). No less than 8 are more than 100km long and whilst the majority are only a few kilometres offshore, the most studied, that of the Spermonde Archipelago, lies 60km offshore from the coastline of south-west Sulawesi. The longest is in the Gulf of Tomini 165km long, running eastwards from the volcanic Togian Islands. The most unique barrier system in Indonesia is the Banggai Barrier Reef running 175km along the southern margins of the Banggai Islands. Part of this barrier consists of lagoonal faro reefs very similar to those found in the Maldives.

Tomascik et al (1997) describe 27 atolls in the waters around Sulawesi. However, whilst many may have the superficial resemblance to open ocean atolls, with annular rims, with or without islands, and various types of lagoonal patch reefs, it is doubtful whether many have developed from volcanic foundations in the relatively simple tectonic setting of a mid oceanic location. Thus these reefs are considered with the further 27 oceanic or
platform reefs as identified by these authors around Sulawesi. They also include open water reefs with continental (not always volcanic) islands and a number of submerged reefs.

These open water reefs occur in clusters around Sulawesi:

• extending to the southwest of Makassar (Ujung Pandang) including Kepulauan (Archipelago) Liukang Tenggaya, K. Tengah


• extending to the west of Makassar, P. Marasende, P. Dewakang-lompo, P. Doandoangan-besar, P. Kalukalukuang


• within and to the south of Teluk Bone, including K. Bone Rate. The best known and best studies of the Indonesian “atolls”, Taka Bone Rate is found here


• to the southeast, including Kepulauan Tukangbesi


• in Teluk (Bay) Tolo, including K. Bowokan


• within Teluk Tomini

Very few of these offshore reefs have been the subject of scientific study.

Although not coral reefs, a closely related habitat which requires similar management and conservation approaches is the area of Halimeda bioherms found at the southern end of the Makassar Strait off southeastern Sulawesi. (Roberts and Phipps, 1988; Phipps and Roberts, 1988). Associated with the Kalukalukuang Bank in particular, these algal reefs may also be found around the margin of the Sunda Shelf towards Kalimantan. Here algal growth is favoured over reef growth as nutrient rich deep Pacific water floods southwards through the Makassar Strait and upwells around the banks and shelf margin.

These islands are all part of one of the worlds most active volcanic island arcs, formed at a tectonic plate subduction zone. Many of Indonesia’s active volcanoes are found here.

Fringing reefs are again ubiquitous, their morphologies depending on the geomorphology of the coastline and the tectonic history of the islands. Many are narrow structures 30 to100m wide with an intertidal reef flat and very sharp seaward drop-off. However, much wider reefs are present. For example around Bali, van Woesik (1997a, in Tomascik et al pp 689-894) indicates the fringing reefs extend 500m from the shoreline.

Although very accessible few of these reefs have been described and there is no systematic description of their distribution. A few areas with more detailed studies or descriptions include:

• Southeastern Bali, where comparative surveys of 1992 and 1997 have been undertaken by van Woesik (1997a, 1997b). Contrasting structure and assemblages were noted on southern aspect reefs open to the high energy Indian Ocean swells and those more sheltered. Strong upwelling of cool oceanic water is also found along the southern side of the whole island arc and is believed to influence the diversity of flora and fauna including the presence of both deep water species and more poleward species, in the shallow coastal waters of the fringing reefs (Tomascik et al 1997, p 698).



• Komodo National Park, where The Nature Conservancy has produced a number of reports on the coastal reefs of Komodo (e. g. Djohani et al, 1999).



• Lembata Island, with 3 active volcanoes and described in detail by Tomascik et al (1997). Fringing reefs may be less continuous along the high energy southern shore of the island but are dominated by well constructed spur and groove systems. On the more sheltered western and northwestern sides facing the Flores Sea, the reefs are more continuous and up to 800m wide, with dense growth of sea grasses on the flats, which in the past may have been the habitat for dugongs.

Similar patterns of distribution may be found in other islands of Nusa Tenggara.

Some 9 barrier reefs are listed by Tomascik et al (1997) in this region (Table 1.4) though some are very close to shore and difficult to separate from fringing reefs. At least a third of the north coast of Flores is bordered by such a barrier with other significant barriers on both north and south coasts of Sumbawa, the north coast of Lombok and near Maumere Bay, P. Besar.

Probably because of the great depth of water away from the volcanic arc islands no open water reefs are found to the south and only two in the Flores/Banda Sea area off the northern shores of Flores (Karang Serbete and Gosong Boni).

The coral reefs of Maluku are regarded as the most extensive and richest in the world but unfortunately detailed descriptions are largely lacking. However, indicative of both rapid growth and species diversity and richness is the report of Tomascik et al (1996) on the rapid coral colonisation of a 1988 lava flow from the Gunung Api volcano in the Banda Islands. Within 5 years of the eruption the flow supported a diverse coral community of 124 species with a coral cover of more than 60%.

Tomascik et al (1997) suggest that some of the most widespread fringing reefs in Indonesia are found even in the turbid waters of the Aru Islands, which consist of 6 main islands and 79 smaller islands separated by long narrow channels. Major fringing reef development is along the shallow east coast where the reef can be up to 15km wide, but narrower reefs are found along the remaining coastlines, except the southern part of the west coast.

15 barrier reefs are listed for Maluku (Table 1.5) with a total length of 425km but so little of this area has been surveyed that this is probably an underestimate. They are associated with the islands of Morotai, Halmahera, Seram, Gorong, Kofiau, Obimayor, Batanme, Nila and K. Tanimbar. Open water reefs, very few if any of which are true atolls, are found in the Banda Sea (Kep. Lucipara and Kep. Penyu) and to the south and east of Halmahera.

West Papua, with a coastline length of 4200km remains one of the least studied areas in Indonesia. Because of high run-off and sediment yield, fringing reefs are missing from significant sections of the coastline, notably from Sarmi to Napainwainrami in Cenderawasih Bay on the north coast and from the Papua-New Guinea border to the Omba river on the south coast. Elsewhere, fringing reefs appear to be very continuous. Tomascik et al (1997) make particular mention of:

• the north coast from Jayapura to the border


• Jayapura to Tg. Kandara, where the reefs are 300-400m wide and westwards to Sarmi


• all the islands of Cenderawasih Bay, 50-100m wide


• on the south coast west of the Omba River


• the southern side of the “Bird’s Neck” between Lakahia Bay and Kamarau Bay and between Tg. Tongerai and Tg. Kirana


• the coastlines along the foothills of Kumafa and Fakfak Mountains


• the northern side of the “Bird’s Head” appears to be suitable for fringing reefs though not the south side which is largely low lying riverine plain.

Barrier reefs are reported in West Papua (Table 1.6), mainly around the islands of Cenderawasih Bay (P. Numfoer, Biak and Supiori) and the islands off the western tip of West Papua (P. Waigeo, Bakanta and Boo). That off the north coast of Waigeo is reported as being 250km long though this seems excessive from the size of the island (c. 120km long).

Open water reefs are also found in close proximity outside the barrier reefs (Cenderawasih Bay and the western extremity of West Papua). Tomascik et al (1997) also list some atolls further offshore in the Pacific Ocean (Bepondi, Ayawi and Mapia) all of substantial size (105-250km²) and possibly true atolls, though little is known about them.

Komodo National Park, in the Lesser Sunda Islands of Indonesia, encompasses a number of islands, the largest of which are Komodo (34,000 ha) and Rinca (20,000 ha). While it is best known for the large endemic lizard, the Komodo dragon, the waters are very rich in marine life, supporting more than 200 hard coral species, seagrasses, mangroves, manta rays, 16 species of cetaceans, turtles, and over 1000 fish species.