General Impact
Predation of corals by Acanthaster planci, storm damage, coral diseases and temperature-related stresses were the most commonly recorded natural impacts to coral reefs. The impact of coral-feeding starfish on natural coral assemblages can be severe and long-lasting. In some reefs 90% of live coral cover is lost. Please follow this link for details on the general impacts of A. planci compiled by the ISSG.
Location Specific Impacts:American Samoa 
Economic/Livelihoods: During historical outbreaks elders report that fishermen could not step onto the reef without stepping on a starfish. As a result, they would stop fishing at night or find new areas where the starfish was still scarce (Birkeland and Lucus 1990). Great Barrier Reef (Australia)
Ecosystem change: In a study by Cameron et al.. (1991) comparing coral reef structure, it was found that coral structure was significantly different between A. planci affected and non-affected sites. Members of the Poritidae family were predominant on outbreak-affected reefs, while members of the Faviidae family were predominant on non-outbreak reefs. In addition few large (old) colonies occurred on the outbreak reefs, whereas such large corals were common on unaffected reefs. Most massive corals are slow-growing, long-lived and have low rates of recruitment and starfish reinfestation will not allow sufficient time for recovery of the massive coral assemblages, favouring the faster-growing, more opportunistic corals. They will be replaced by algae and non-massive coral assemblages in the intervals between outbreaks. The recent devastating outbreaks appear to be abnormal perturbations coincident with large-scale human activities on the Great Barrier Reef, rather than integral features of reef ecology.
Detailed information about the impacts of A. planci on the Great Barrier Reef can be found at the Reef monitoring: Australian Institute of Marine Science website.
Modification of natural benthic communities: A study by Lourey et al.. (2000) of reefs in the Great Barrier Reef revealed that hard coral cover on reefs with Acanthaster planci outbreaks declined at a mean annual rate of 6% to an average level of 9%. A total of 78% of recovering reefs showed a positive growth rate, assuming linear growth. Tthe time for coral cover to increase by 30%, was estimated at between 5 years to well over 1000 years. In addition to providing regional estimates of the decline and recovery of reefs due to A. Planci outbreaks, this study highlights the variability in rate of recovery between reefs and raises the possibility that not all reefs will recover from sustained outbreaks. Similarily a study by Seymour and Bradbury (1999) showed that the average reef recovery time is lengthening over time, showing it is harder for reefs to recover from outbreaks of A. Planci recently compared to earlier years and indicating that key features of reef community structure have been damaged over time. Green Is. (Australia) (Australia)
Economic/Livelihoods: There was concern in 1963 and 1964 over the burgeoning numbers of Acanthaster planci and the subsequent coral mortality, which was threatening the tourist attractions of the island (Birkeland and Lucus 1990). Green Island is the reef most frequently visited by tourists on the Great Barrier Reef and tour-boat operators had to remove A. planci from the bottom of their glass-bottoms boats. The effort proved futile and operators turned to the government for help in protecting their livelihoods.
Detailed information about the impacts of A. planci on the Great Barrier Reef can be found at the Reef monitoring: Australian Institute of Marine Science website.
Modification of natural benthic communities: Outbreaks of the coral-feeding starfish Acanthaster planci have caused high levels of mortality and injury in corals on the Great Barrier Reef. In surveys conducted in 1985 and 1986, it was estimated that the starfish had decimated a quarter of the massive Porites spp. corals surveyed at five reefs (John Brewer, Rib, Potter, Feather and Green Island) (Done 1988). Davies Reef (Australia)
Ecosystem change: A study conducted by Done et al.. (1991) compared benthic community structure and coral population structures on three disturbed reefs (Vaipahu - Moorea; Rib and John Brewer Reefs - Great Barrier Reef [GBR], Australia) and one undisturbed reef (Davies Reef - GBR). Moorea barrier reefs had been invaded by tall macrophytes Turbinaria ornata and Sargassum sp., whereas the damaged GBR reefs were colonised by a diverse mixture of short macrophytes, turfs and coralline algae.
Detailed information about the impacts of A. planci on the Great Barrier Reef can be found at the Reef monitoring: Australian Institute of Marine Science website. Feather Is. (Australia)
Modification of natural benthic communities: Outbreaks of the coral-feeding starfish Acanthaster planci have caused high levels of mortality and injury in corals on the Great Barrier Reef. In surveys conducted in 1985 and 1986, it was estimated that the starfish had decimated a quarter of the massive Porites spp. corals surveyed at five reefs (John Brewer, Rib, Potter, Feather and Green Island) (Done 1988). Grub Reef (Australia)
Economic/Livelihoods: Damage by Acanthaster planci on Grub Reef has been so intense that tour boats that previously frequented the island stopped visiting, as too few living coral remained on the reef (Birkeland and Lucus 1990). John Brewer Is. (Australia)
Ecosystem change: A study by Done and colleagues (1991) compared benthic community structure and coral population structures on three disturbed reefs (Vaipahu - Moorea; Rib and John Brewer Reefs - Great Barrier Reef, Australia) and one undisturbed reef (Davies Reef - Great Barrier Reef). Moorea barrier reefs had been invaded by tall macrophytes Turbinaria ornata and Sargassum sp., whereas the damaged Great Barrier Reef reefs were colonised by a diverse mixture of short macrophytes, turfs and coralline algae.
Modification of natural benthic communities: Outbreaks of the coral-feeding starfish Acanthaster planci have caused high levels of mortality and injury in corals on the Great Barrier Reef. In surveys conducted in 1985 and 1986, it was estimated that the starfish had decimated a quarter of the massive Porites spp. corals surveyed at five reefs (John Brewer, Rib, Potter, Feather and Green Island) (Done 1988). Potter Is. (Australia)
Modification of natural benthic communities: Outbreaks of the coral-feeding starfish have caused high levels of mortality and injury in corals on the Great Barrier Reef. In surveys conducted in 1985 and 1986, it was estimated that the starfish had decimated a quarter of the massive Porites spp. corals surveyed at five reefs (John Brewer, Rib, Potter, Feather and Green Island) (Done 1988). Rib Is. (Australia)
Ecosystem change: A study by Done and collegues (1991) compared benthic community structure and coral population structures on three disturbed reefs (Vaipahu - Moorea; Rib and John Brewer Reefs - Great Barrier Reef, Australia) and one undisturbed reef (Davies Reef - Great Barrier Reef). Moorea barrier reefs had been invaded by tall macrophytes Turbinaria ornata and Sargassum sp., whereas the damaged Great Barrier Reef reefs were colonised by a diverse mixture of short macrophytes, turfs and coralline algae.
Modification of natural benthic communities: Outbreaks of the coral-feeding starfish Acanthaster planci have caused high levels of mortality and injury in corals on the Great Barrier Reef. In surveys conducted in 1985 and 1986, it was estimated that the starfish had decimated a quarter of the massive Porites spp. corals surveyed at five reefs (John Brewer, Rib, Potter, Feather and Green Island) (Done 1988). Cocos (Keeling) Islands
Modification of natural benthic communities: Cocos Island coral reefs were damaged by the 1982-83 El Niño event with 1987 surveys revealing dramatic coral mortality at all depths (1-24m) and live coral cover as low as 3% in some places. Remaining coral was being further degraded by high densities of the corallivores A. planci and Arothron meleagris (the Guinea fowl pufferfish) and the bio-eroder Diadema mexicanum (Mexican Pacific sea urchin), which was responsible for the erosion of large reef framework areas. It is predicted that the recovery period of the original reef-framework thickness is in the order of centuries. Cano Is. (Costa Rica)
Modification of natural benthic communities: Around the Biological Reserve of Cano Island, Pacific Costa Rica, there are five large coral reef flats built mainly of dead Pocillopora spp. At present, they are covered mainly by crustose coralline algae and microatolls of Porites lobata. From the upper reef slope to the reef base several corals grow in small patches (e.g., Pavona clavus, Pavona varians, Pavona gigantea, Gardineroseris planulata, Psammocora superficialis, Pocillopora elegans, Pocillopora damicornis); the massive coral Porites lobata is predominant. Pocilloporid species are predominant on most other eastern Pacific reefs. The distribution, abundance and feeding preferences of corallivorous organisms (e.g. A. planci, Arothron meleagris, Pseudobalistes naufragium, Quoyula monodonta) on the deeper reef suggests that most pocilloporids are affected and limited by them. Sinai (Egypt)
Modification of natural benthic communities: Coral cover is reduced in south Sinai by as much as 30%. Outbreaks of the coral-feeding starfish may be caused by over-fishing of reef-associated fish predators in the families Lethrinidae, Balistidae and Tetraododontidae (Ormond et al.. 1990, in PERSGA/GEF 2003). Fiji
Economic/Livelihoods: The occurrence of Acanthaster planci on the reefs of the Mamanuca group (Fiji) are worrying, as the area is a noted tourist destination (WWF 2003).
Modification of natural benthic communities: Acanthaster planci outrbreaks can result in large areas of reefs being destroyed in Fiji (WWF 2003). French Polynesia (Polynésie Française)
Ecosystem change: Coral communities at Moorea (French Polynesia) were severely depleted by disturbances early in the 1980s. Corals were killed by the predatory starfish A. planci, by cyclones, and/or by depressed sea level. A study by Done et al.. (1991) compared benthic community structure and coral population structures on three disturbed reefs (Vaipahu - Moorea; Rib and John Brewer Reefs - Great Barrier Reef, Australia) and one undisturbed reef (Davies Reef - Great Barrier Reef). Moorea barrier reefs had been invaded by tall macrophytes Turbinaria ornata and Sargassum sp., whereas the damaged Great Barrier Reef reefs were colonised by a diverse mixture of short macrophytes, turfs and coralline algae. Corals occupying denuded areas at Vaipahu, Rib and John Brewer were small (median diameter 5cm in each case) and sparse (mean 4-8m-2) compared to longer established corals at Davies Reef (median diameter 9cm; mean 18m-2). At Moorea, damselfish and sea urchins interacted with corals in ways not observed in the Great Barrier Reef sites. Territories of the damselfish Stegastes nigricans covered much of Moorea's shallow reef top. They had significantly higher diversity and density of post-disturbance corals than areas outside of territories, suggesting that the damselfish exerts some influences on coral community dynamics. Sea urchins on Moorea (Diadema setosum, Echinometra mathaei, Echinotrix calamaris) were causing widespread destruction of dead standing coral skeletons. Overall, it appears that the future direction and speed of change in the communities will be explicable more in terms of local than regional processes.
Modification of natural benthic communities: Present and past Acanthaster planci grazing is considered to be the main causative agent of coral destruction at Moorea. A. planci showed a feeding preference for all growth-forms of Acropora. The species Montipora spp. and Pocillopora spp. were both commonly grazed. Foliate Pavona were grazed to a lesser extent and Montastrea, Favia, Synarea and Porites were rarely grazed (Faure 1989). Double Reef (Guam)
Modification of natural benthic communities: Approximately 50% of the reef from Double Reef was reported dead due to starfish predation (Chesher 1969). Piti Bay (Guam)
Modification of natural benthic communities: Since 1967, Acanthaster planci has killed well over 90% of the living coral along 38km of coastline of Guam from just below spring tide level to the depth limit of reef coral growth, which is about 65 metres (Chesher 1969).
Reduction in native biodiversity: After the death of coral polyps due to A. planci at Piti Bay (Guam), the coralla are rapidly overgrown with algae. Most fish leave the dead reefs, with the exception of small, drab-coloured herbivorous scarids and acanthurids (Chesher 1969). Tanguisson Reef (Guam)
Modification of natural benthic communities: At Tanguisson Reef, Guam, the 1968-1969 explosion of Acanthaster planci devastated the coral community. In the wake of this predation, coral species richness, density and cover were drastically reduced and the species composition was altered. In two of three reef zones examined, <1% coral cover remained. At the time of disturbance, some considered the magnitude of this and similar Acanthaster disturbances unprecedented and predicted long recovery times because reefs were viewed as mature, stable communities (Colgan 1987).
The preference of A. planci for Montipora and Acropora temporarily shifted composition to nonpreferred prey such as Porites and Leptastrea. By 1981 (year 12) species richness, cover and composition matched measurements of comparable reefs before the disturbance. This rapid recovery from a natural disturbance demonstrates that some coral communities have a greater resilience than once estimated (Colgan 1987).
Reduction in native biodiversity: After the death of coral polyps due to Acanthaster planci at Tanguisson Reef (Guam), the coralla have become overgrown with algae. Most fish leave the dead reefs, with the exception of small, drab-coloured herbivorous scarids and acanthurids. Tumon Bay (Guam)
Modification of natural benthic communities: Since 1967 Acanthaster planci has killed well over 90% of the living coral along 38km of coastline of Guam from just below spring tide level to the depth limit of reef coral growth, which is about 65 metres. By spring 1968 almost all of the coral off Tumon Bay was dead (Chesher 1969).
Reduction in native biodiversity: After the death of coral polyps due to Acanthaster planci at Tumon Bay (Guam), the coralla are rapidly overgrown with algae. Most fish leave the dead reefs, with the exception of small, drab-colouted herbivorous scarids and acanthurids (Chesher 1969). Red Sea (Indian Ocean)
Modification of natural benthic communities: Recent extensive coral mortality on offshore Red Sea reefs was similar in appearance to that following outbreaks of A. planci. Nearly all the acroporid corals - the preferred food of the coral-feeding starfish - were dead. Papua (Irian Jaya) (Indonesia)
Ecosystem change: In the early 1980s, significant coral mortality attributed to A. planci was reported from northern Irian Jaya (Lane, 1996). Pulau Panteh reef (Indonesia)
Ecosystem change: In 1996, a massive infestation of Acanthaster planci was observed on the southern extremity of Pulau Panteh reef in the Banggai Islands group (Sulawesi, Indonesia). Coral mortality adjacent to the starfish aggregations appeared close to 100% (Lane, 1996). Iriomotejima Is. (Japan)
Modification of natural benthic communities: A long-term monitoring study was conducted at Iriomotejima Island (Ryukyu Islands, Japan) to explore the responses of adult fish assemblages to the recovery of coral degraded by an outbreak of A. planci. In 1987, five years after the outbreak, all of the arborescent (branching) corals had been broken apart and the reef had changed into a flat plain of rubble. Species richness and the numerical density of fish on the dead reef had severely decreased. Natural recovery of the dead reef was initiated in 1989, mainly by larval recruitment of branching Acropora corals. Since that time, fish species richness and density on the recovering reef have increased steadily with the increasing percentage cover of live corals. In 1995 to 1997, when the reef had almost 100% live coral cover, fish assemblages had about a 90% resemblance to those on a nearby reef untouched by A. planci. These results demonstrate that the structure of the disturbed fish assemblage had returned to its pre-perturbation state on the recovery of the coral reef (Sano 2000). Madagascar
Modification of natural benthic communities: The most frequently observed damage of coral reefs was from the coral predator A. planci. Damage by Acanthaster planci appeared to be localised. Majuro atoll (Marshall Islands)
Modification of natural benthic communities: Evidence of damage from Acanthaster planci is apparent on the reefs of the Marshall Islands. Along the south-western lagoon shore of Majuro, branching and tabulate Acropora species have been decimated, with over 90% mortality rates recorded in 2004 and 2005 (Pinca et al. Undated). Mauritius
Modification of natural benthic communities: Mauritian reefs have been subject to degradation owing to a number of factors, including massive predation by Acanthaster planci (Fagoonee 1990). Pis Is. (Northern Mariana Islands)
Modification of natural benthic communities: Bands of Acanthaster planci on Pis Island corresponded to a band of Acropora reticulata coral on which the starfish were feeding. Surveys revealed belts of A. reticulata were completely destroyed and A. planci had moved into shallower water to attack other coral species and growth forms (Tsuda 1971). Rota Is. (Northern Mariana Islands)
Modification of natural benthic communities: Twenty-seven years after a major Acanthaster planci outbreak on Rota, Saipan and Tinian, coral cover has increased and reef community structure has changed. Many of the reefs are now dominated by species of the family Poritidae, particularly, Porites rus and P. cf. lutea. A. planci and Culcita novaeguineae remain present in low densities on most of the reefs surveyed and continue to keep the populations of Acroporidae and Pocilloporidae low (Quinn and Kojis 2003). Saipan Is. (Northern Mariana Islands)
Modification of natural benthic communities: Twenty-seven years after a major Acanthaster planci outbreak on Rota, Saipan and Tinian, coral cover has increased and reef community structure has changed. Many of the reefs are now dominated by species of the family Poritidae, particularly, Porites rus and P. cf. lutea. A. planci and Culcita novaeguineae remain present in low densities on most of the reefs surveyed and continue to keep the populations of Acroporidae and Pocilloporidae low (Quinn and Kojis 2003). Tinian Is. (Northern Mariana Islands)
Modification of natural benthic communities: Twenty-seven years after a major Acanthaster planci outbreak on Rota, Saipan and Tinian, coral cover has increased and reef community structure has changed. Many of the reefs are now dominated by species of the family Poritidae, particularly, Porites rus and P. cf. lutea. A. planci and Culcita novaeguineae remain present in low densities on most of the reefs surveyed and continue to keep the populations of Acroporidae and Pocilloporidae low (Quinn and Kojis 2003). Garapan (Northern Mariana Islands)
Modification of natural benthic communities: In a 1970 resurvey at Garapan, 80-90% of the corals were found to be dead and Acanthaster planci had disappeared (Tsuda et al. 1970). Oman
Modification of natural benthic communities: In the Gulf of Oman, Acanthaster planci caused widespread and selective coral mortality during a population outbreak. Starting in 1978-79, with diminishing effects to 1982, coral reefs with high acroporid coral cover experienced high mortalities - with virtually all Acropora spp. eliminated on many reefs. Reefs with high pocilloporid coral cover largely escaped predation, probably because Acanthaster planci encountered difficulties in traversing continuous stands of this coral: the coral's nematocysts and the presence of symbiotic crustacean guards deter the starfish. Thus, where environmental conditions are suitable for reef development, sporadic, high level Acanthaster planci predation can modify coral community structure through the differential survival of coral prey and hence lead to the development of A. planci resistant reef types (Glynn 1993). Palau
Modification of natural benthic communities: Recent coral bleaching has left relatively little live coral on the reefs, particularly the staghorn and table Acropora corals that are the favourite food of A. planci (Palau Conservation Society 1999).
Reduction in native biodiversity: Native reef fish, which depend on coral reefs for protection, are negatively affected by the reduction in living coral caused by A. planci in Palau (Birk 1979). Samoa
Economic/Livelihoods: During historical outbreaks, elders report that fishermen could not step on the reef without stepping on A. planci. In order to fish they would have to stop fishing at night or find new areas where the starfish was still scarce to avoid injury (Birkeland and Lucus 1990). Saudi Arabia
Modification of natural benthic communities: Abundance of the coral-feeding starfish, Acanthaster planci was assessed in the Farasan Islands in 1999 and was believed to be contributing to coral mortality in the islands (Al-Yami and Rouphael 1999 2000, in PERSGA/GEF 2003). Large populations of A. planci on patch reefs in the Al-Wajh Bank are causing substantial reductions in living coral cover (Devantier et al.. In Press). Kona Is. (United States (USA))
Modification of natural benthic communities: On Kona, in the Hawaiian islands, Acanthaster planci prefers to prey on the smaller colonies of Pocillopora meandrina over the far more abundant Porites compressa and P. lobata (Chess et al. 1997).
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