With over 11,000 square kilometers of coral reefs there is a wide range of reef types harboring highly varied morphologies and ecological communities. The island arcs provide excellent examples of atoll development, from volcanic coastlines with only sporadic coral communities through high islands with fringing reefs, to partially submerged volcanoes with barrier reefs, and finally true atolls. In the north and south the Hawaiian and Austral Archipelagos both provide examples of the latitudinal limits to reef development, with decreases in both diversity and reef constructions in the cooler waters away from the tropics. Polynesia also marks the edge of the Indo-Pacific region. Species diversity is relatively low in almost all species groups, and there are marked declines in diversity as one moves eastwards.

In modern times this region has become an area of contrasts. A number of countries and states remain remote and isolated with small populations dependent on fisheries. Tourism has become a very important economic resource for a few countries. In particular Tonga, French Polynesia and Hawaii. Traditional utilization and management of reef resources has largely been lost in the more developed islands, and there are typical problems of overexploitation and pollution associated with the areas of most intense human development. In all, however, the extent of such pressures remains localized, and there are vast areas of reefs in good condition.

Hawaii is largely populated by people of non-Polynesian origin and traditional uses of coral reefs have almost completely ceased. Alongside these changes Hawaii has developed the most extensive network of marine protected areas in the entire Pacific Ocean outside Australia 

Tuvalu is a small archipelago consisting of five true atolls and four other platform islands with encircling fringing reefs. There are also other seamounts which may reach within 30 meters of the surface.

The lagoons are predominately sandy with some coral heads. The outer slopes are reported to be rich in both coral cove and diversity. Some 400 fish species have been recorded from Funafuti. There are small mangrove stands in a few areas.

Wallis and Futuna consists of three main islands: Wallis, Futuna and Alofi. All are high volcanic islands of volcanic origin. Wallis has fringing reefs around most of its coastline and is further completely encircled by a barrier reef, with a number of sand cays on the reef edge. There is only a small number of deeper channels into the lagoon proper. Futuna has narrow fringing reefs on all coasts, while the uninhabited Alofi has only a few such areas.

Fishing is an important activity, although largely still operating at a subsistence level. However, there have been records of blast fishing. Fringing reefs around Futuna may have been impacted by sediment runoff and are reported to be degraded. There is no significant tourism  to the islands, and there are no formal management regimes or protected areas.

OFFICIAL, SCIENTIFIC & GOVERNMENTAL SITES:
BBC: Tuvalu


Tokelau is a small group of three small coral atolls, each with numerous islands on its rim. The lagoons are shallow with large numbers of coral outcrops, while the maximum height of the islands is about 4.5 meters. Tokelau, a territory of New Zealand, is heavily dependent on financial support for development. Concerns about degradation of the natural environment from over fishing and sewage pollution have led  to some efforts to improve environmental management. At the end of the 1990's the overall threats to coral reefs was very low, although there had been a depletion of a number of species such as giant clam and trochus.

Samoa is dominated by the two large islands of Upolu and Savaii with a few very small islands nearby. There are fringing reefs around most of the island's coastlines. Information about biodiversity is relatively limited. About 50 species of hard coral have been listed, although this is likely to be a considerable underestimate. Studies of marine algae  have been more complete, and some 300 species have so far been described. Some 991 fish species have been recorded in the wider Samoan archipelago, of which at least 890 are shallow reef-dwelling species. There are small areas of seagrass, and mangrove communities are well developed at a few locations around Upolu.

The people of Samoa are generally heavily dependent on the reefs at a subsistence level and for the domestic market. An estimated 4,600 tons of fish were taken for subsistence in 1997, while domestic markets probably add a further 75-80 tons of fish, crustaceans and other invertebrates. There has been a noted reduction in biomass and size of fish in shallower and more heavily fished areas. As the country develops there are increasing problems of pollution from sewage and solid waste. Poor land use practices combined with uncontrolled use of agricultural chemicals are creating high loads of nutrients, toxic chemicals and sediments, placing the reefs under increasing levels of stress. Tourism, the fastest growing sector of the economy, is also causing some problems, particularly in the development of hotel facilities.

Samoa has only one marine protected area, although the Tafua Rainforest Reserve contains some coastal areas, and there are plans to develop others. There are also increasing efforts to involve village participants in conservation awareness. Traditional marine tenure is recognized, maintaining traditional ownership of adjacent lagoon and reef fishery resources by the villages.

American Samoa is the eastern portion of the Samoa Archipelago and consists of five high volcanic islands, and in the east, Rose Atoll. These islands are surrounded by fringing reefs, with reef flats typically 50-500 meters wide terminating in a reef slope which drops sharply for 3-6 meters and then descends gradually down to a depth of about 40 meters.

Biodiversity is similar to Samoa's, with 890 species of reef fish recorded around the entire archipelago. Some 200 coral species have been recorded. There are also small areas of mangrove on the islands of Tutuila and Aunuu, and the reef rim of Rose Atoll is dominated by coralline algae. It has an important green turtle nesting colony, and having been cleared of rats is also a thriving seabird colony.

The vast majority of the rapidly growing population of American Samoa lives on the southern shores of Tutuila. Over fishing is a problem on this island, and there are further problems arising from land-derived sediments and pollutants. Although there is sewage treatment in the main population centers there are still some nutrients inputs from sewage in these areas and elsewhere. There are two tuna canneries which used to add considerable amounts of nutrients to Pago Pago harbor. These inputs have now been substantially reduced with the construction of a treated waste disposal pipe further offshore, and the dumping of high nutrient waste at some 8 kilometers distance. The coastline on Tutuila has been heavily impacted by road building and construction and nesting turtles have largely stopped using this area. A number of reefs and related habitats have been declared as protected areas.

OFFICIAL, SCIENTIFIC & GOVERNMENTAL SITES:
Fagatele Bay National Marine Sanctuary
National Park of American Samoa
Rose Atoll National Wildlife Refuge
Samoan Sensation: The Coral Reefs of Samoa

Tonga's islands stretch for over 800 kilometers from north to south, and consist of both relatively low-lying limestone islands and high volcanic ones. To their east is the Tonga Trench, which at nearly 11,000 meters is one of the deepest points in the ocean. Tectonic activity in the country is considerable and many islands and shoals in the west are too volcanically active at the present time for reef development. In the eastern part of Tonga however, reefs are widespread and well developed. There are fringing reefs surrounding most coasts, while platform and barrier-type structures are also located in most of the main island groups. The most extensive area of reefs are in the Hapa'ai group.

Artisanal fisheries are an important activity in the country. Studies have shown that almost 70 percent of the catch is made up of reef fish (notably emperors and mullet). Turtle eggs and meat are still eaten in many areas. There are also several important commercial fishers, notably an aquarium trade dealing in fish, coral and live rock together with limited numbers of invertebrates. Over fishing is a problem in areas of high population density, especially around Tongatapu. The problems of over fishing have been exacerbated by a lack of local ownership of reef resources, enabling commercial collectors to harvest even close to local communities. In addition of over fishing, certain relatively destructive fishing practices appear to be degrading reefs.

Eutrophication is a problem in Tongatapu and Vava'u, arising from both untreated sewage and fertilizer runoff. Further problems have been noted resulting from the building of causeways in Ha'apai and Vava'u, while quarrying, construction and sand mining create problems in some areas.

Tourism is particularly important for Tonga, with over 30,000 visitors in 1999.  A number of protected areas have been established, largely focused around Tongatapu.

Niue consists of a single uplifted coral atoll, oval in shape and reaching a maximum height of about 70 meters above sea level. It is actually one of the largest carbonate islands in the Pacific. The island is almost surrounded by a narrow platform cut into the former reef structure and forming a modern reef flat, becoming discontinuous in the south and east. Few details are known about the diversity of the reefs, although 243 marine fish have been reported and there are reported to be over 43 coral genera.

OFFICIAL, SCIENTIFIC & GOVERNMENTAL SITES:
Nuie Government Website
Niue Island
JaneResture.com: Tonga
Official tourism site for Nuie Island

COMMERCIAL:
Nuie Dive
The Kingdom of Tonga
Tonga Scuba Diving Guide

The Cook Islands are a group of 15 islands, or island groups, scattered across a wide expanse of ocean. Descriptions typically divide the islands geographically into a northern and southern group. The northern Cook Islands are a group of five atolls and a platform island, while the southern islands show a wide range of oceanic types.

The biodiversity of Cook Island reefs has not received a great deal of attention, however it is clear that they lie at some distance from the mega-diverse areas of the Western Pacific. It is suggested that the diversity and abundance of species is greatest around the high (volcanic) islands and lowest around the uplifted islands. The Cook Islands lie east of the natural distribution of mangroves and none are recorded.

In the Cook Islands, utilization by the islanders on coral reefs is considerable. In 1996 about 70 percent of all households undertook at least some form of subsistence fishing, including both gleaning from reef flats and boat based fishing. Marine resources are also extensively used in exports, with large black pearl farms in Maniniki Atoll providing the main source of export income.  Tourism is an important industry for the Cook Islands, which receive about 100,000 visitors per year. Snorkelling and diving are popular activities.

There are some human impacts on reefs, particularly associated with urban and agricultural development. Sedimentation, chemical and nutrient pollution are all potential threats. Sea-level rise associated with climate change could present significant problems for a number of low-lying islands and associated reefs. Although a number of protected areas are listed it is the low population densities and the remote location of many  reefs that offer the greatest protection.

OFFICIAL, SCIENTIFIC & GOVERNMENTAL SITES:
JaneResture.com: Cook Islands

COMMERCIAL:
Dive Site Directory: Rarotonga, Cook Islands


French Polynesia represents one of the largest territories in the Pacific and incorporates some 6,000 square kilometers of coral reefs. It is divided into five distinct archipelagos, each following a chain oriented from northwest to southeast. Four of these archipelagos trace the movement of the earth's crust over volcanic hotspots and their structures are younger in the southeast, where there are a number of high islands.

The Marquesas, a group of high volcanic islands together with a number of smaller islets and shallow banks, form the northernmost archipelago. They lie in the path of the westward flowing South Equatorial Current and are climatically quite distinct from the others islands, with very low rainfall showing a peak in June. Their northerly latitude places them relatively close to the equator so they are rarely impacted by cyclones. Despite this, reef development is poor. There are short stretches of fringing reefs and many less clearly defined structures. These reefs are very young, and their diversity is low.

The Tuamotus make up the largest and geologically the oldest archipelago. They consist of low coralline atolls, with the exception of Makatea, which is raised, reaching some 113 meters above sea level.  These atolls include some of the largest in the Pacific -Fakarava at 1,400 square kilometers and Rangiroa at nearly 1,800 square kilometers, with some 240 islands along its atoll rim. Taiaro Atoll near the center of the group is slightly uplifted, with a completely enclosed lagoon. The closure of this lagoon is thought to have been relatively recent, and there are some surviving reef communities despite their apparent isolation and the raised salinities.

The Society Islands are among the best known in the region. Mehetia in the southeast is an active volcano with only sparse coral development along its coastline. Tahiti is the largest island in the country. Like the neighboring Moorea it is a high volcanic island with vertiginous slopes. The coastlines of both islands have discontinuous fringing reefs and are surrounded by offshore barrier reefs, each broken by numerous passes. To the northwest many of the islands have similar structures with high central islands and barrier reefs; however, Maupiti is a near-atoll, and the remaining structures to the northwest are true atolls.

The Gambier Islands lie at the southeastern end of Tuamotus, and sometimes considered as part of this larger group. They represent the eastern extent of French Polynesia. The main islands are a cluster of four large volcanic islands (Mangareva, Taravai, Aukena and Akamaru) surrounded by a single barrier reef. These and other smaller islands in the lagoon show some fringing reef development. The small atoll of Temoe is sometimes considered part of the Gambier group.

The Austral Islands lie to the southwest and include the rock pinnacles of Marotiri (Bass Islands) and the high volcanic island of Rapa in the far southeast. These are the southernmost islands of the region, with relatively low sea temperatures. There are no fringing reefs although there are significant coral communities. Porites and Pachyseris corals are absent, and algal cover is high. The remaining islands in the Austral group lie much further north and have well developed fringing and barrier reefs.

The reefs of French Polynesia include some of the best studied in the Pacific, but there are nonetheless some 50 islands or atolls which have never been visited by scientists. Information is particularly limited describing the Gambier, Marquesas and Austral archipelagos. Located in in the most eastern region of the Indo-Pacific, diversity is generally relatively low, particularly on a unit-area basis. Some 168 coral species, about 800 reef fish, 30 echinoderms, 346 species of algae and 1,159 mollusks have been recorded. There appear to be some general patterns in the dominant species among different reef types. The lagoons of high volcanic islands are dominated by Porites, Acopora, Psammocora, and Synaraea, while in lagoons only Porites and Acropora dominate, and in the near-closed lagoons only Acropora. Outer slopes largely harbor Pocillopora, Acorpora and Porites, with coral cover ranging from 40 to 60 percent at a depth of 15 meters. Even the deeper reef slopes have high coral cover, with over 90 percent cover in some atolls, down to 90 meters. There are some distinctive features about the communities in each of the archipelagos and, although general rates of endemism are low, there are a number of unique species recorded from the Marquesas and Gambier archipelagos.

The majority of islands and reefs in French Polynesia are remote from significant human populations and remain largely unimpacted by human activities. Fishing is critical for all of the populated islands, but particularly for those more remote from urban and tourism developments. One of the major industries in the country is black pearl culture, which employs around 5,000 people at 600 farms on some 50 islands. This industry supplies about 98 percent of the world market in black pearls and earns about $130 million per annum.

Tourism is another major industry on some islands, with 164,000 visitors in 1996.  All hotel developments are coastal, and a number of hotels extend over the reef flat on jetties or pontoons. While hotels are required to treat their wastewater there may be some introduction of nutrient-rich waters into the lagoons or via the groundwater. Coastal development more generally has led to considerable modifications of the coastline in Tahiti and Moorea. Sewage pollution is also a problem close to urban areas in these two islands, which they also have high levels of sediment runoff, possibly exacerbated by pesticides and fertilizers, which may have localized impacts. In Tahiti it has been estimated that 20 percent of reefs in urban areas have been destroyed, while 75 percent of the fringing reefs in Bora-Bora, which is one of the most popular tourist destinations, have been moderately to severely disturbed. Overall, however, the total extent of these impacts is low or very low compared to the total area of reefs in French Polynesia.

Only protected areas currently incorporate coral reefs, making up a tiny portion of the total reef area in the country. There are ongoing efforts to increase the total area protected, and to develop community-based management systems for a number of atoll lagoons.

The Pitcairn Islands are the easternmost islands of the Indo-Pacific region and consist of a small group of island. Pitcairn itself is a relatively recent volcanic island reaching some 347 meters above sea level, around which there are no coral reefs. Other islands in the group, Henderson, Ducie and Oeno have fringing reefs showing low biodiversity. The reefs and islands are largely protected by their isolation, and Henderson Island is a World Heritage Site.

Clipperton Atoll is located in the Eastern Pacific, about 1,100 kilometers southwest of the Mexican part of the American mainland. It is a roughly circular atoll about 4 kilometers across, with an island completely encircling its lagoon. There is a 50-200 meter wide reef terminating in a spur and groove system. The reef slope is relatively gentle with high coral cover (33-83 percent) in many areas. The deeper slope has sand and rubble.

This atoll is extremely important in biogeographic terms. Its easterly location actually places it in a completely different biogeographic region from other Pacific islands -the Tropical Eastern Pacific, with close affinities to the reefs and coral communities of the western coast of the Americas. It is in fact the best developed reef and the only atoll in the Tropical Eastern Pacific. Biodiversity is very low, with 18 recorded scleractinian coral species and 115 fish species. The island is unihabitated and rarely visited. There is no legal protection of its natural resources.

OFFICIAL, SCIENTIFIC & GOVERNMENTAL SITES:
JaneResture.com: Tahiti
NASA's Earth Observatory: Coral Bleaching in French Polynesia

COMMERCIAL:
Macgillivray Freeman's Coral Reef Adventure: Tahiti & Rangiroa
Dive Discovery: Tahiti
Nations Online: French Polynesia
Tahiti Vacation Planners: The Islands of French Polynesia

The Hawaiian Islands are the most isolated archipelago in the world, lying considerably north and east of the vast majority of the Pacific Islands. They were formed as the Pacific tectonic plate moved northwest over a stationary hotspot beneath the ocean floor. The youngest island in the group is thus the island of Hawai'i in the southeast, which shows near continuous volcanic activity. Together with seven other main islands, it forms a distinct block of high volcanic islands making up the majority of the land area in the archipelago. Moving northwest, the older volcanic islands have largely subsided and there is a long chain of islands and reefs at or near sea level leading to Kure Atoll in the northwest. These latter reefs lie some distance north of the tropics. Further north and west of these is the sequence of Emperor Seamounts extending for thousands of kilometers towards the Kamchatka coastline of Siberia. These represent former reef-capped volcanic islands. Their northward migration took them to latitudes where reef growth was insufficiently rapid to keep up with crustal subsidence, and then out of the regions of hermatypic coral growth completely.

Fringing reefs are by no means continuous among the high islands of the southeast, although they are well developed in a number of places, particularly on leeward (southern and southwestern) shores. Along the coast of Hawai'i there are no true fringing reefs, but well developed submerged reefs occur along the western Kona coast. Recent underwater lava flows provides a substrate for looking at colonization by reef organisms ins the south and east. Fringing reefs are better developed in a few locations along the western shores of Maui, the southern shores of Molokai and the northeastern shores of Lanai. Oahu has a number of well developed reefs, including a well studied fringing reef in Hanauma Bay and one of the only barrier reefs in Kanohoe Bay, which protects a large number of patch reefs and a coastal fringing reef. Fringing reefs  are found around much of the coastline of Kaua'i but remain poorly developed around Niihau. There is a submerged barrier reef off the western coast of Kaua'i.

The majority of Hawai'i's reefs are located northwest of the main Hawaiian Islands. These are found on the  smaller islands of Nihoa, Necker, French Frigate Shoals, Gardner Pinnacles, Laysan and Lisianski Islands, and the Pearl, Hermes, Midway and Kure Atolls. The location of the Hawaiian Islands, in considerable location and on the northern edge of the tropics, has meant that they are not highly diverse. Their isolation has been emphasized by the dominant oceanic currents which reduce the likelihood of pelagic larvae being carried to the archipelago from other areas. Over millions of years one consequence of this has been the considerable opportunities for the development of new species. Some 52 species of stony coral, 500 of nearshore fish, 1,000 of marine mollusks, and 450 of marine algae have been recorded, of which typically about 25 percent of each of these and other groups are endemic to the Hawaiian Islands and a few nearby reefs. This is the highest level of endemism for any coral reef area in the world. One particular feature of Hawaiian coral reefs is the relative scarcity of acroporid corals, the major reef builders in most parts of the Pacific.

Millions of seabirds nest in the northwest Hawaiian Islands, and a number of migratory shorebirds nest or overwinter here. These are among the largest and most important seabird colonies in the Pacific Ocean. Five species of marine turtles have been seen in Hawaiian waters, and the French Frigate Shoals are one of the largest remaining nesting grounds for the green sea turtle in the Pacific. These same islands are also of critical importance for the Hawaiian monk seal Monachus shauinslandi. The closest relatives of this seal are the critically endangered Mediterranean monk seal and the extinct Caribbean monk seal. Although there are about 1,500 individuals and they are highly protected, numbers are still declining. Several other marine mammals are found in the islands, including a large and growing population of humpback whales, Megaptera novaegliae, which spend part of their migratory cycle in the islands between November and May during which time they mate and give birth.

The Hawaiian Islands are one of the world's top tourist destinations and consequently only a few of the residents now live in a manner that could be described as subsistence, or depend heavily on their own fish catches. There are, however, many who fish to supplement their diet. for recreational purposes or at small-scale commercial levels. All of these operate with modern equipment, including gill nets, spears, trolling, surround nets and traps. In addition to these, recreational and commercial collection of fish for aquaria is widespread and poorly regulated. The nearshore fish populations are reported to be depleted around nearly all the main islands. Larger scale commercial fisheries primarily focus on pelagic species, but also concentrate on a number of reef species. A spiny lobster fishery in the northwestern islands is reported to be severely overfished and may be closed. More recently a major shark fin fishery has developed which is extremely controversial, not least because of the waste and cruelty of returning living sharks to the water with no fins.

European settlement led to radical changes in the terrestrial environment, with the degradation or clearance of large tracts of native forest by settlers  and the feral animals (goats and deer in particular) that accompanied them. These changes have also let to considerable sedimentation in nearshore environments and may have killed many reef communities. Hawai'i is also one of the few places where significant numbers of exotic species have been introduced to the coral reef environment, including marine algae and fish. There is evidence that these are spreading and may be displacing resident reef species in some areas.

With urbanization there have been problems of sewage discharge in a number of areas. Efforts to reduce this have led to better treatment in some places, but also to more remote discharge into deeper waters. The overall effects of the latter approach remain controversial, but are still likely to be impacting reefs in some areas.

Tourism is the major industry in Hawai'i, heavily focused on locations on the larger islands. Coastal tourism developments, including golf courses, may be adding to the stresses by wider coastal development, effluent discharge and the physical disturbance of nearshore communities. Diving and snorkelling are popular , although limited in some areas by rough seas and currents. Hana'uma Bay, the most popular snorkelling destination on Oahu, receives up to 10,000 visitors per day.

Efforts to regulate and protect coral reefs in Hawai'i include a large number of marine protected areas. Federal legislation covers most of the more remote islands and their surrounding reefs as national wildlife refuge. In 2000 all of the other reefs and shallow banks which lay outside these declared refuges, together with a very large area of surrounding seas, were declared a Coral Reef Ecosystem Reserve. The combined legislation for these areas has created a contiguous marine protected area, second in size only to the great Barrier Reef in Australia.  Among the main islands the Hawaiian Humpback Whale National Marine Sanctuary covers significant areas of offshore waters. Closer to centers of human population there are several sites protected at the state level. The degree of protection afforded by these varies considerably.

The US minor outlying islands include American Samoa, Guam and the Northern Mariana Islands but also a number of remote atolls and reefs in the Central Pacific. Their importance in terms of biodiversity is now increasingly recognized. These include Baker and Howland Islands, the Phoenix Islands of Kiribati, Jarvis Island,  Johnston and Wake Atolls.

OFFICIAL, SCIENTIFIC & GOVERNMENTAL SITES:
Carl Meyer's Home Page: Hawaiian Coral Reef Topics
Coral Reef Network: Hawaii
Hawaii Coastal Zone Management
Hawaii Wildlife Fund
Hawaiian Whale Reseach Foundation
Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve
Turtle Trax: Green Sea turtles on Maui
Enchanted Lake Elementary School's "Venture into Hawaii's Coral Reefs"
NOAA Center For Coastal Monitoring and Assessement: Coral Reef Report -Hawaii
Save Our Seas Hawaii Based Site
COMMERCIAL:
Alternative Hawaii- The Hawaii Ecotourism Site
Dive Makai
Eco Maui
Ed Robinson's Diving World Adventures
Kohala Divers
Maui Scuba Diving
Snorkel Maui
 

Extracted and adapted from The World Atlas of Coral Reefs, by Mark D. Spalding, Corinna Ravilious and Edmund P. Green, published by the University of California Press . For more complete and in-depth coverage of the topics presented in this webpage, I recommend highly purchasing a copy of this beautifully illustrated book. Just click on the University of California Press link above to do so.