Report: Healthy Marshall Islands' Coral Reefs Face New Threats
"Today, coral reef ecosystems in the Marshall Islands are in excellent condition. The outer and less populated atolls in particular support healthy and diverse communities of marine life. However, in recent years, the coral reefs in the Marshall Islands have become increasingly threatened by pressures of fisheries, climate change and sea-level rise, increased urbanization and a loss of cultural traditions."
A 569-page report, the third in an ongoing series of assessments of the condition of coral reef ecosystems in the United States and Pacific Freely Associated states by NOAA’s Coral Reef Conservation Program, evaluates the impacts of thirteen major threats and summarizes the current conservation management activities being implemented in the 15 jurisdictions. Highlights from the Marshall Islands Chapter follow:
More Highlights from Marshall Islands Chapter:
For example, the outer atolls in RMI suffer from occasional forays of fishers involved in the live fish trade and illegal shark finners. Coral reefs near the population centers at Majuro atoll (30,000) and Ebeye (15,000) are far more impacted by fishing and pollution than other parts of the RMI.
Many of the Marshall Islands’ coral reefs remain unexplored, but capacity for coral reef assessment and monitoring is growing. Over the past few years, the College of the Marshall Islands (CMI), Natural Resource Assessment Surveys (NRAS), Coastal Management Advisory Council (CMAC), Marshall Islands Conservation Society and the Re-Imman Project Team have collected baseline information on the condition of RMI coral reefs with strong support from the Marshall Islands Marine Resources Authority (MIMRA), local communities and local governments. The CMI Marine Science program is helping to build local capacity for conservation. A national database of survey data for six atolls is maintained at the CMI and MIMRA offices. The information presented in this chapter is based on these surveys, personal observations by CMI staff and reports of a University of Hawaii expedition to Ailinginae atoll in 2002. A long-term comprehensive monitoring project is underway at Rongelap and similar efforts are under development for Majuro, Ailuk and other atolls in the future.
Conservation and sustainable resource management has always been a part of Marshallese traditional culture. The increasing threats to marine resources have strengthened commitment within the RMI government and communities to establish and manage community-based conservation areas in addition to other resource conservation strategies.
Over the last decade, various efforts have been made to establish community-based conservation areas on different atolls. Those conservation initiatives have been led either by MIMRA, as part of the development of sustainable local fisheries, by the national Environment Protection Authority (RMIEPA) or by local atoll governments (e.g., Mili’s 2003 efforts have stalled, but a recent initiative on Ailuk established management areas and a management plan for the atoll).
Other communities and leaders are seeking protection through international conservation efforts, such as the nomination of Ailinginae and Bikini Atolls for inclusion on the United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site list.
In 2006, the president of the Marshall Islands signed the Micronesia Challenge, a commitment by Micronesian countries and territories to “effectively conserve” 30% of nearshore marine and 20% of terrestrial resources by 2020. The need for an overarching framework for conservation area planning was recently addressed by development of a national document outlining the principles, process and guidelines for the design, establishment and management of conservation areas that are fully owned and endorsed by local communities based on their needs, values and cultural heritage (Re-Imman Project Team, 2008).
Climate Change and Coral Bleaching
Because the country is comprised of numerous low-lying islands that depend on intact coral reef ecosystems for protection from erosion, the RMI is particularly threatened by climate change and associated sea level rise. Among the anticipated effects of climate change are an increasing incidence of storms, drought and sea level rise. Recently Majuro Atoll suffered both a serious storm (October 2006) and an extended drought, which led to the declaration of a water emergency.
Sea level rise
The Intergovernmental Panel on Climate Change’s (IPCC) 3rd Assessment Report (IPCC, 2001) reported that sea level has been rising an average of 0.01 to 0.02 m per century since 1000 BC, but the 4th Assessment (IPCC, 2007) established that sea level rise over 20th century was 0.17 m. For various emissions scenarios and with a nominal allowance for ice sheet effects, the IPCC projects sea level rise in the 21st century to be between 0.18 and 0.79 m, but the report also cautions that “larger values cannot be excluded” since the “understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea-level rise” (IPCC, 2007). Rahmstorf (2007) analyzed the tendency of observed sea level rise to exceed the upper limit of IPCC forecasts, and projected a total 21st century sea level rise of 0.5 to 1.4 m unless mitigation measures are implemented.
The land area of the Marshall Islands averages about 2 m above sea level (www.rmiembassyus.org/Environment.htm); the highest elevations are generally found along shorelines with lower elevations inland (ELP, unpub. data). RMI government is very concerned with sea level rise. The potential impact of sea level rise has been demonstrated quite dramatically during extreme high tides when the groundwater lens rises above the surface in the low-lying areas. Building dykes and pumping would be impractical to maintain land below sea level, as the soil substrate is porous coral rubble. Construction of seawalls is equally unfeasible as it would require islanders to mine nearshore areas for building materials, similar to the blast mining that occurs on Majuro reef flats (Barnett and Adger, 2001) and the widespread hand mining of beaches (McKenzie et al., 2006).
There is currently a move to dredge sand and gravel from lagoons (Smith and Collen, 2004) in order to conserve ocean reefs. Ocean reefs are an initial line of defence against the sea as they dissipate wave energy, provide habitat for foraminiferans which make up most of the sand in the lagoon and cement together reef structure. Holthus et al. (1992) estimated a 7% loss to the Marshall Islands gross national product with a 1 m sea level rise through application of the Bruun (1962) rule for beach erosion. But Forbes and Solomon (1997) assert that the Bruun rule is “clearly inappropriate where shorelines have responded to past high water levels by progradation rather than recession, and where the nearshore profile is constrained by the reef flat.” A regional high stand of sea level at about 2-3 m above the present level in 2000 B.C. (before human habitation) was responsible for the formation of island foundations (Dickinson, 2006). The current population center at Majuro Atoll, however, is not situated on this relatively high land at Laura, but on much lower and partially reclaimed land.
Bleaching
Corals in the Marshall Islands have been spared from mass bleaching events like those that have impacted Palau and the Caribbean, but observations made primarily on Majuro indicate that modest bleaching events have occurred on at least five occasions. Bleaching events in the RMI, which usually are restricted to intertidal depths, were first observed in an undated photographed used for tourism promotion between 1998 and 2000. An event beginning in September 2001 during a period of calm, cloudless weather (Abraham et al., 2005; Pinca et al., 2005) resulted in considerable coral mortality, which intensified and spread to slightly greater depths during low tides in October and November 2001. Mortality among shallow Acropora colonies on both lagoon and ocean shores was well documented (Jacobson, unpub. data). Local knowledge suggests that similar events did not occur in the RMI previously.
Coral bleaching at deeper sites was observed on Majuro in both 2003 and 2006. The 2003 event involved Acropora, Porites, Millepora and other colonies down to depths of at least 10 m. In 2006, up to 5% of massive Porites spp. colonies within the northern lagoon were entirely or partially bleached, but with no apparent mortality (Figure 12.3). At several lagoon sites, up to 90% of Acropora colonies also bleached, leading to significant mortality (approximately 20-50%) down to 3 m depth. Significantly, many massive Faviid and Platygyra colonies growing at 5-8 m on the fore reef bleached and suffered “crown” mortality in 2006. This pattern of mortality primarily affects the top surfaces of colonies and can result in scars that persist for many years; such scars had not been observed previously on Majuro (Jacobson, unpub. data). Recent subtidal bleaching events have been largely restricted to a few species and usually result in a low overall incidence of bleaching (typically less than 20% of all coral below several meters depth). The 2003 and 2006 events occurred during a period of elevated sea water temperatures which may have contributed to a subsequent coral disease outbreak. Widespread bleaching was observed on corals in the lagoon of neighboring Arno atoll in December 2006 (Richardson, unpub. data). The atoll’s population of Isopora cuneata, an important reef-building species, was severely reduced or impacted. Only shaded colony bases survived.
Few reports of coral bleaching have emerged from outer atolls, but this is more likely due to a lack of monitoring and not a lack of bleaching. A visit to Jaluit atoll in 2003 and 2004 permitted scientists to document a dramatic subtidal bleaching event and subsequent coral mortality there. Bleaching on Jaluit during this event was restricted to tabulate colonies of A. robusta, a form uncommon on Majuro.
Diseases
Coral disease in the Marshall Islands is not yet well characterized. An outbreak of Acropora white disease affecting tabulate colonies on the exposed outer reefs in Majuro is the most intensively documented case so far. A bacterial pathogen, Vibrio coralliilyticus, which has been shown to be the cause of white plague type II in the Caribbean, was isolated from Majuro lagoon in 2004; the bacteria is known to co-occur with a large histophagous ciliate and results in brown band disease in corals of Australia’s Great Barrier Reef. The outbreak of Acropora white disease has persisted for at least seven years, with a peak during 2003-2004. The peak of the outbreak coincided with the highest temperatures recorded at a lagoon site over a ten year period, and coral bleaching occurred on site at the end of 2003, indicating a possible link between temperature and disease virulence.
In 2006, disease incidence remained relatively low (annual mortality was 5% of live tabulate Acropora area) as it had in 2005, compared to a peak of 16% mortality in 2004. The sustained monitoring of this outbreak has revealed an interesting change in disease symptoms. In 2006 and 2007, table corals were found with large disease-killed lesions, yet little or no signs of disease spreading is visible (i.e., if any white band is present, it is restricted to a small portion of the edge of the lesion). Clearly, corals are not dying as rapidly as they had in 2004. However, following a return of warm conditions in 2006, disease incidence in 2007 appears to be increasing once again.
Two other rarely seen disease syndromes affect Platygyra and Goniastrea spp., which display progressive overgrowth with green filamentous algae (spreading at a rate of mm per week), and Turbinaria, in which multiple lesions expand at a rate of 2-4 cm per year. These cases of disease were found only on the southern, pollution-impacted shore of Majuro. Coralline lethal orange disease is also common on Majuro along the southern shore, and typically spreads at a rate of 1-2 mm/day (Jacobson, in prep.)
Tropical Storms
The Marshall Islands are continuously buffeted by the Pacific Ocean. Narrow strips of land, most of which is less than a meter above high tide, are subject to erosion during storms from surge and large waves. Climate change related storms and associated surge waves threaten coral reef communities, terrestrial natural resources and the livelihood of thousands of people in the Marshall Islands. Past typhoons and tidal waves have devastated parts of Majuro, Arno, Mili, Jaluit, Likiep and Namdrik atolls, and such storm phenomena are expected to continue and possibly intensify with global warming.
An October 7, 2006 storm (which later became Typhoon Soulik) caused large surf and a storm surge that flooded areas of Majuro, inundating parts of the highway and destroying a section of the airport seawall. Large tabulate Acropora colonies were damaged, coral rubble and trash were deposited on the island and some breadfruit trees were killed when salt water pooled around their roots. Fortunately, beach erosion was partially or completely offset by the transport and accumulation of coral rubble. However, the long-term effects of coastal erosion are readily apparent on Majuro, where waves have undercut the shoreline, causing the collapse of coastal land and coconut palms. Recovery of coral reef communities from single and chronic catastrophic events, such as, storms is expected to be slow in situations where the physical environment has been altered (Connell, 1997)
The threat of increased coastal erosion and the loss of some lagoon beaches have prompted a move to outlaw shore dragline dredging on Majuro. Of the two alternatives, suction dredging and importing aggregate, the latter is more expensive. As a result, plans are being made to suction dredge materials from deeper (below 10 m) areas of the northern lagoon where accumulation “deltas” of foraminifera sand are found (see the Associated Biological Communities sec-tion of this chapter for a summary of the area’s foraminifera ecology). However, land owners in the northern lagoon oppose this choice, so it is likely that suction dredging will be restricted to areas of the southern la-goon, despite the disadvantage of smaller grain size. Finding environmentally friendly local sources of aggregate and hard rock is more problematic.
Coastal Pollution
Due to the collapse of the solid waste collection system between 2004 and 2007 (e.g., corroded dumpsters and broken down trucks) and insufficient toilet facilities, much household waste, as well as most fecal waste, was simply deposited along Majuro’s shoreline. The lack of an effective seawall barrier at the landfill allowed large amounts of floating garbage to escape, blanketing down-current shores with myriad bits of plastic refuse, especially bags and diapers, which can be found in the water column, particularly during high wave events. Much of this garbage becomes entangled on coral. The solid waste landfill on Majuro is nearing capacity. A local non-governmental organization (NGO), the Marshall Is-lands Conservation Society, with New Zealand and U.S. funding, has implemented a new recycling program to increase composting of plant waste (with cardboard soon to be included) and begin community battery collections in an attempt to extend the life of the landfill and divert toxics from the environment.
Regardless of improvements in waste management, black leachate continues to escape from the landfill onto the adjacent reef flat with potentially serious ramifications for the reef ecosystem. For this reason it is crucial to prevent the development of new landfills elsewhere on the atoll. In early 2007, the responsibility for solid waste collection was placed under a single authority, the Majuro Atoll Waste Corporation. Despite a perennial shortfall of funding, the corporation has succeeded in fortifying the seawall and stabilizing the refuse with a cover of sand dredged from the lagoon.
Although incineration has been proposed as an alternative waste manage-ment strategy, the high cost of the incinerator and concerns over hazardous by-products (e.g., toxic emissions and ash) has prevented adoption of this option. Though the use of plastic bags and Styrofoam packaging for food is clearly unsus-tainable, these practices persist in urbanized areas and are expanding to outer atolls. In a small step in the right direction, the CMI has committed itself to use only biodegradable packaging, and encourages its vendors to do the same
Tourism and Recreation
The good of RMI’s coral reefs and islands, and the historical significance of the RMI appeals to SCUBA divers, sport fishers and World War II history enthusiasts. The coun-try currently hosts approximately 6,000 visi-tors per year, of which 20% (roughly 1,200) are tourists, primarily from the U.S. and Japan (Figure 12.9). On Majuro, the areas of the northern lagoon are in excellent con-dition and remain the focus of reef-related tourism. Most of these developments con-sist of small-scale resorts on northern islets and a few dive shops. In 2007, the first in a series of Japanese charter flights brought in a large group of SCUBA tourists to Majuro. Other than the small number of yachts visit-ing RMI’s outer atolls each year, few tourist operations exist on outer atolls, largely be-cause of unreliable air transport.
On Bikini Atoll, a community-based SCUBA diving center attracts tourists eager to explore a historic collection of WWII wrecks and visit Shark Pass, a part of the atoll that has received international attention thanks to a spectacular population of grey reef sharks. Unfortunately, the shark population at Bikini was significantly depleted by a recent visit from a single illegal shark fishing operation, highlighting the vulnerability of these outer islands to illegal fishing.
A new resort is under development on Rongelap that will allow tourists to visit the atoll, which has been virtually inaccessible since the nuclear tests conducted in the 1950s. Plans have also been announced for the development of a large-scale Korean golf resort and paved airport on Wotje Atoll, which will require the relocation of the population center to adjacent islets. A lack of other local economic opportunities makes the plan attractive to locals, and this reality tends to override concerns about the potentially harmful affects of excess water and nutrients on the marine and terrestrial environment. While outer atoll destinations offer unparalleled diving and fishing opportunities, the remoteness of these atolls is a barrier to tourism development as well as environmental surveillance capacity.
Fishing
Copra has historically been the RMI’s sole cash crop. Over the past ten years, however, increased production from Southeast Asian countries has negatively impacted the price of copra and, as a result, RMI has focused more heavily on its fisheries for income. The RMI’s Exclusive Economic Zone of over 2,128,970 km2 (822,000 mi2) supports a large population of high-grade tuna, including skipjack, yellowfin, bigeye and albacore. The RMI fisheries operate in accordance with the Forum Fisheries Agency, the regional fisheries regulatory body. The RMI, through the Ministry of Resources and Development, is pursuing a number of development opportunities in fisheries and maintains bilateral fishing agreements with several countries, including Japan, Korea and Taiwan. The licensing fees charged to foreign fishing vessels generate the majority of revenue from this resource.
A China-based fish processing plant is currently under construction on Majuro and is scheduled to begin operations in early 2008. The new plant will supply cooked loins for the canned tuna industry. Due to the wide variety of retail operations, dry dock and harbor facilities, the availability of international air service and access to fuel supplies, Majuro is a competitive location for fishery growth in the region.
Sharks, a valuable tourism resource, have declined in many parts of the Pacific. While some believe that the RMI still supports robust reef shark populations, there is evidence that shark populations are starting to decline (Figure 12.10). Shark fins continue to be exported from Majuro, allegedly as bycatch from the long line tuna fishery. There seems to be little concern for the fate of shark populations among the Marshallese, who fear sharks for their perceived danger.
Trade in Coral and Live Reef Species
Captive breeding or aquaculture ventures in RMI are a boom and bust business. The most successful operations include MIMRA- operated tridacnid clam hatcheries on Majuro, Likiep, Mili and Arno Atolls. Coral fragments are also produced sustainably for the ornamental aquarium trade and are marketed to North America and Europe. Collection of live aquarium fish takes place primarily in Majuro, but also on Arno and Mili, and continues to be unregulated and unmonitored. Many high value target species (e.g., some butterflyfish and angelfish) are found only in deep (>50 m) habitats; their natural history is largely unknown and therefore the sustainability of these fisheries cannot be assessed. In 2006, over 52,000 individual fish were exported from Majuro (D. Jacobson, pers. obs). Various attempts have been made to farm rabbitfish (Siganus spp.), sea cucumbers and seaweed on various atolls in the country. CMI has promoted aquaculture via the Arrak research station, a research facility that includes classrooms, an algal culture laboratory, a basic science laboratory, an indoor hatchery, larval rearing tanks and grow-out facilities. In 2007 an Australian company began operating a fish farming operation that imports juveniles of barramundi cod (Cromileptes altivelis) for grow-out in the Majuro lagoon. The Black Pearls of Micronesia project is one of the first commercial pearl farms on Majuro.
Ships, Boats and Groundings
Shortly before Christmas 2006, a 23 m abandoned Indonesian style wooden boat drifted onto the southern Majuro shore, where it became entrapped on the reef flat (Figure 12.11) and shifted back and forth along the shore for six days. After it cleared the reef, it continued drifting westward, smashing a narrow band of coral and dislodging large chunks of substrate along 10 km of shore. Efforts to remove the vessel failed.
In the spring of 2007, the near sinking of a dive boat at its mooring led to it being towed across the lagoon and intentionally beached in shallow water in an attempt to salvage the vessel. This resulted in a diesel spill, the destruction of several dozen Porites colonies and the near-destruction of an endemic three banded anemone fish colony (Figure 12.12). This site is a popular, formerly intact snorkeling area in the northern lagoon of Majuro. Litigation resulting from this incident is ongoing and has the potential to result in a landmark, precedent-setting ruling for local environmental law enforcement.
Marine Debris
Due to their location within the northern equatorial current, Marshall Island atolls receive large amounts of marine debris, primarily composed of glass, plastic, rubber and other products which accumulate on the shorelines of all atolls (Figure 12.13). Based on the identity of bottles and identification of floating seeds, it appears that some of the debris originates from as far as Central and South America (Vander Velde and Vander Velde, 2006).
In addition to receiving marine debris from distant locations, Majuro exports a large amount of plastic trash to the Pacific current system. An extraordinary amount of rubbish can be found in the reef habitats of Majuro, on both ocean and lagoon shores.. Disposable diapers are among the most abundant and destructive debris because they stick to corals and do not degrade for lengthy periods of time. Continual abrasion kills the local coral polyps. Plastic bags and other plastic products can reach surprisingly high densities in the water column.
Aquatic Invasive Species
Although macroalgae of the genus Kappaphycus was briefly introduced and successfully cultivated in Majuro lagoon in 2002 as a pilot aquaculture project, this potentially invasive brown algae has evidently not become naturalized. Some years ago Acanthophora spicifera, another macroalgae species, became abundant in Majuro lagoon.
The potential exists for the non-native humpback grouper (Cromileptes altivelis) which was recently imported for aquaculture in lagoon cages, to become naturalized. The giant clam species Tridacna derasa was introduced as an aquaculture species, and anecdotal evidence suggests that individuals still survive at Mili and Arno atolls.
Security Training Activities
The military base at Kwajalein Atoll was established in 1964 and supports the research and development needs of U.S. space and defense programs. The facility provides strategic missile defense program support as the Ronald Regan Ballistic Missile Defense Test Site (RTS), where the military conducts research, development, testing and evaluation using cutting-edge radar, optical and telemetry sensors. The $4 billion strategic military base and the large lagoon at Kwajalein Atoll provide an ideal location for testing long-range missiles launched from the continental U.S. and short to intermediate range missiles launched from elsewhere in the Pacific. In addition to military operations, RTS supports NASA and Department of Energy initiatives.
Offshore Oil and Gas Exploration
There are currently no offshore oil and gas exploration activities occurring in the RMI.
Other
Crown-of-thorns Sea Star (COTS)
No published record of elevated COTS (Acanthaster plancii) population numbers in the RMI occurred in the three decades following an event in the early 1970s, when a large outbreak triggered a professional control effort across Micronesia led by Westinghouse personnel from San Diego (D. Jacobson, unpub. data). However, in 2004 several concentrated aggregations (over 1,000 animals/km2) were found in Majuro’s southwestern lagoon and northern pass. Although this outbreak has subsided in most monitored regions without significant human intervention, dense aggregations persisted in some areas in 2007, including one to the west of the northern pass. Most of the lagoon is not currently monitored for COTS, so data on their abundance and distribution is collected opportunistically.
A pilot control project conducted in Majuro during the initial stages of the 2004 outbreak removed over 900 animals from a 1 km long segment of fringing reef in the southwestern lagoon. Despite these efforts, the region suffered heavy coral mortality when other COTS replaced the removed individuals.
The result of this lagoon outbreak was over 90% mortality among Acropora, heavy mortality among massive colonies such as Pavona spp. and Lobophyllia spp., and locally high mortality (50-75% mortality, mostly in the west) among massive Porites colonies (D. Jacobson, unpub. data; Figure 12.14). The loss of large Porites colonies, which are estimated to be more than 100 years old, is significant, especially considering that COTS generally avoid consuming Porites spp. elsewhere (D. Jacobson, unpub. data). In the northern reaches of the lagoon, a patchwork of devastated reefs are interspersed with areas of low mortality.
Pavona cactus, Acropora, Goniastrea and many other species have been heavily impacted, with more than 95% overall coral mortality on some formerly pristine, highly diverse reefs (D. Jacobson, unpub. data).
On the ocean shore, predation by COTS caused high mortality among large table corals off Majuro’s west coast (near the town of Laura) in areas where disease mortality was also high. The outbreak seems to have spread to the east where COTS have continued to attack massive Porites colonies while avoiding branching or columnar species of Porites (i.e., P. rus and P. cylindrica). A number of smaller COTS (< 25 cm) have recently been observed near the airport. During a brief visit to Ebon atoll in 2005, lagoon reefs exhibited significant damage associated with a COTS outbreak that persisted throughout the 1980s and 1990s. Ebon’s ocean reefs appear to have largely escaped mortality. Because most of the lagoon’s coral colonies had been devoured previously, by 2005 Ebon lagoon’s COTS population was comprised of only about a dozen animals that were observed on a large patch reef (D. Jacobson, unpub. data). A very small population of eight COTS was also found on a small patch reef in Ailuk lagoon in June 2006. COTS are routinely found in low abundance on islands such as Majuro and Likiep. Efforts to collect additional information on COTS populations at other atolls will be facilitated by the installation of an environmental radio network, which will improve communication between atolls. - (Report, pp. 398-395)
