INTRODUCTION AND SETTINGThe reefs of the Marshall Islands are among the most pristine in the Indo-Pacific, having suffered minimal damage from bleaching, destructive fishing techniques, and sedimentation. University of California Press,Berkeley,USA.421p. Prepared at the UNEP World Conservation Monitoring Centre. The USA maintains a military presence in these islands and continues to operate the Kwajalein Missile Range on Kwajalein Atoll. It may be that these are among the most “pristine” coral reef communities in the region. One positive result of this has been significant increases in some fish groups, including predators such as sharks and jacks (Carangidae) on the surrounding reefs. Since the 1960s human pressures on these evacuated atolls (Bikini, Enewetak and Rongelap have been repopulated and re-evacuated on different occasions up to the present day) has been minimal. The detailed impacts of these tests on the coral reef environment are still unknown, although there were obviously significant physical affects in the areas of direct impact, while a number of large ships were also sunk in the atoll lagoons. A study carried out in 1994 confirmed that some 15 atolls and islands were subject to some radioactive fallout during the 1950s, although most of them are now considered clear. The largest test, the Bravo hydrogen bomb at Bikini, measured 15 megatons (1 000 times the strength of the Hiroshima bomb): fallout from this explosion was carried to the inhabited atolls of Rongelap, Ailinginae, Rongerik, Utrik and others. These tests were carried out on land, in the air near ground level or over the water. Perhaps the best known “use” of the atolls of the Marshall Islands was nuclear weapons testing by the USA in the 1940s and 1950s, when some 67 nuclear detonations were performed on Bikini and Enewetak atolls.
Sealevel rise associated with climate change is a particular threat to these low-lying islands. There is also a limited amount of aquaculture development, focussed on clams (for the aquarium trade), pearl oysters and trochus. Shark fins are obtained as by-catch from the tuna fisheries.
Some high value species are also being exploited, including trochus, giant clams and marine turtles. Commercial fishing is largely restricted to foreign-licensed tuna vessels, but there is also an aquarium fishery which has been operating out of Majuro for about 20 years, largely exporting to Hawaii. However, artisanal fishing remains very important, and is now being more widely encouraged. There has been some breakdown of traditional landuse and cultural systems, exacerbated by the considerable movements forced during the nuclear testing (see below). Much development has taken place with little concern for the environment, and the mining of lagoon sand to obtain building materials is widespread. Consequently there are various environmental problems, including sewage and solid waste pollution. Two thirds of the population live on Majuro and Ebeye where they are concentrated into a relatively small area. Politically the Marshall Islands form an independent state, but exist in a “free association” with the USA. All of the islands lie close to sea level with a mean height of about 2 meters. Dating work on the fossils at the base of these, together with the youngest basalt rock below, indicated that this volcanic activity occurred 50-59 million years ago. Deep drilling into the reefs of Bikini and Enewetak atolls revealed a sequence of reef deposits ranging from 1.3 to 1.4 kilometers thick overlying basalt rock from the original volcanic activity. The two chains were probably formed by plate movement over a volcanic hotspot, although there is no current volcanic activity. Kwajalein, at some 2 500 square kilometers, is the largest atoll in the Pacific. The atolls are typically circular to elliptical with shallow lagoons. In all there are some 1 136 islands dispersed over a vast area of ocean, although the total land area is very small. Wake atoll, to the north, is clearly linked to this group biologically and geologically, but is separately administered by the USA (see Chapter 14). The isolated atolls of Enewetak and Ujelang lie to the west of these main chains. The Marshall Islands are a complex of 28 coral atolls and 5 small (non-atoll) islands lying in two broad chains, the eastern Ratak (sunrise) chain and the western Ralik (sunset) chain.
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