|Scientific Name:||Porites lobata|
|Species Authority:||Dana 1846|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor/s:||Sheppard, A., Fenner, D., Edwards, A., Abrar, M. & Ochavillo, D.|
|Reviewer/s:||Livingstone, S., Polidoro, B. & Smith, J. (Global Marine Species Assessment)|
The most important known threat for this species is extensive reduction of coral reef habitat due to a combination of threats. Specific population trends are unknown but population reduction can be inferred from estimated habitat loss (Wilkinson 2004). It is widespread and very common throughout its range, is moderately susceptible to bleaching but recovers quickly, and therefore is likely to be more resilient to habitat loss and reef degradation because of an assumed large effective population size that is highly connected and/or stable with enhanced genetic variability. Therefore, the estimated habitat loss of 18% from reefs already destroyed within its range is the best inference of population reduction since it may survive in coral reefs already at the critical stage of degradation (Wilkinson 2004). This inference of population reduction over three generation lengths (30 years) does not meet the threshold of a threat category. However, this species is susceptible to bleaching and disease and is collected for the aquarium trade, therefore it is listed as Near Threatened. However, because of predicted threats from climate change and ocean acidification it will be important to reassess this species in 10 years or sooner, particularly if the species is also observed to disappear from reefs currently at the critical stage of reef degradation.
|Range Description:||This species is found in the Red Sea and the Gulf of Aden, the southwest and northern Indian Ocean, the Persian Gulf, the central Indo-Pacific, Australia, South-east Asia, Japan and the South China Sea, the oceanic West Pacific, the central and eastern Pacific, and the Hawaiian Islands, Johnston Atoll, Palau and the Mariana Islands (Randall 1995).
In the Eastern Tropical Pacific region, this species is present in: Mexico: Nayarit, Jalisco, Colima and Guerrero (Reyes-Bonilla and López-Pérez 1998, Reyes-Bonilla et al. 2005, Reyes-Bonilla 2003, Reyes-Bonilla et al. 1999, Reyes-Bonilla 2001, Ketchum and Reyes-Bonilla 2001, Pérez-Vivar et al. 2006, Glynn and Ault 2000, Guzmán and Cortés 1993); Costa Rica: Peninsula de Santa Elena, Culebra Bay, Brasilito Bay, Sámara, Cabo Blanco, Bahía Ballena, Punta Leona, Manuel Antonio, Punta Dominical, Punta Uvita, Peninsula de Osa, Golfo Dulce, Caño Island and Cocos Island (Cortés and Guzmán 1998, Cortés and Jiménez 2003, Alvarado et al. 2005, Guzmán and Cortés 1993, Glynn and Ault 2000); Panama: throughout the Gulf of Panama and Chiriquí (Maté 2003, Guzmán et al. 2004, Guzmán and Cortés 1993, Glynn 1997, Glynn and Ault 2000); Colombia: Malpelo Island, Gorgona Island, Ensenada de Utría and Tebada (Zapata and Vargas-Ángel 2003, Glynn and Ault 2000, Guzmán and Cortés 1993); Ecuador: Salango Island, Los Frailes, Sucre Island, and La Plata Island in mainland Ecuador, and throughout the Galápagos Islands (Glynn and Wellington 1983, Glynn 2003, Glynn and Ault 2000, Hickman 2005, Guzmán and Cortés 1993); Clipperton Atoll (Glynn et al. 1996, Glynn and Ault 2000).
Native:American Samoa (American Samoa); Australia; Bahrain; British Indian Ocean Territory; Cambodia; Chile; China; Christmas Island; Cocos (Keeling) Islands; Colombia; Comoros; Cook Islands; Costa Rica; Djibouti; Ecuador; Egypt; El Salvador; Eritrea; Fiji; French Polynesia; Guadeloupe; Honduras; India; Indonesia; Iran, Islamic Republic of; Iraq; Israel; Japan; Jordan; Kenya; Kiribati; Kuwait; Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius; Mayotte; Mexico; Micronesia, Federated States of ; Mozambique; Myanmar; Nauru; New Caledonia; Nicaragua; Niue; Northern Mariana Islands; Oman; Palau; Panama; Papua New Guinea; Philippines; Pitcairn; Qatar; Réunion; Samoa; Saudi Arabia; Seychelles; Singapore; Solomon Islands; Somalia; Sri Lanka; Sudan; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Tokelau; Tonga; Tuvalu; United Arab Emirates; United States Minor Outlying Islands; Vanuatu; Viet Nam; Wallis and Futuna; Yemen
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – southeast; Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
This species is probably the most common Porites, especially in the Eastern Tropical Pacific. According to Guzmán and Cortés (1993), P. lobata is one of the most important hermatypic coral from the south section of the Eastern Tropical Pacific region. Additionally, Cortés and Guzmán (1998), considered P. lobata as the most important reef framework builder in the Caño and Cocos Islands, Costa Rica.
There is no species specific population information available for this species. However, there is evidence that overall coral reef habitat has declined, and this is used as a proxy for population decline for this species. This species is more resilient to some of the threats faced by corals and therefore population decline is estimated using the percentage of destroyed reefs only (Wilkinson 2004). We assume that most, if not all, mature individuals will be removed from a destroyed reef and that on average, the number of individuals on reefs are equal across its range and proportional to the percentage of destroyed reefs. Reef losses throughout the species' range have been estimated over three generations, two in the past and one projected into the future.
The age of first maturity of most reef building corals is typically three to eight years (Wallace 1999) and therefore we assume that average age of mature individuals is greater than eight years. Furthermore, based on average sizes and growth rates, we assume that average generation length is 10 years, unless otherwise stated. Total longevity is not known, but likely to be more than ten years. Therefore any population decline rates for the Red List assessment are measured over at least 30 years. Follow the link below for further details on population decline and generation length estimates.
|Habitat and Ecology:||
This species is frequently a dominant species of back reef margins, lagoons and some fringing reefs, and can be found generally to depths of 30 m.
It is one of the predominant framework builders (Glynn 2000), sometimes building monospecific reef frameworks or contributing to pocilloporid reef building (Glynn 2001). Porites lobata is a relatively slow-growing species with reported growth rates of 8.4 mm/year in Costa Rica and 8.1 mm/year in the Galápagos; however it can grow as fast as 14 to 19 mm/year during the first few years (Guzmán and Cortes 1993, Cortés and Guzmán 1998, Guzmán and Cortés 1989).
P. lobata utilizes a gonochoristic reproductive strategy (except from Caño Island, Costa Rica), and is presumably a broadcaster spawner (Glynn et al. 1994). Glynn et al. (1994) suggested that eastern Pacific populations appeared to be reproductively active over multiple annual intervals, including periods of relatively low temperature. According to Glynn et al. (1994), fecundity can vary between regions; P. lobata has higher fecundities at Caño Island, Costa Rica, and Uva Island, Panama, than in the Galápagos Islands, where water temperatures are lower and more seasonally variable. Moreover, Glynn et al. (1994) suggest that P. lobata reproduces twice per year in thermally high and stable environments. Fecundity of this coral appears to benefit from moderate sea warming events, but may decline dramatically during unusually strong thermal anomalies (Glynn et al. 1994). After 1983, observations of sexual recruitment have been rare to infrequent in the eastern Pacific; however sexual recruitment has been observed in some areas of the Galápagos Islands (Glynn et al. 1994). The almost complete absence of sexual recruitment for this species in the eastern Pacific may be due to high larval mortality in the water column; as well as increased levels of competition with benthic alga, and increased densities of grazers and bioeroders following the 1982-83 El Niño event (Glynn et al. 1994).
Porites lobata can also reproduce asexually by fragmentation (Guzmán and Cortés 1989, Cortés and Guzmán 1998, Cortés and Jiménez 2003). In the eastern Pacific the incidental feeding activities of the triggerfish Pseudobalistes naufragium can generate fragments that survive to form new colonies (Guzmán and Cortés 1989, Cortés and Guzmán 1998, Glynn et al. 1994). This form of fragmentation is common in Costa Rica and Panama, but uncommon in the Galápagos Islands (Glynn et al. 1994). Fragmentation also occurs by initial weakening of colonies by bioeroders; P. lobata colonies possess high densities of boring bivalves (Lithophaga spp.), which erode the skeletal structure, a process that can also lead to fragmentation (Cortés and Jiménez 2003, Glynn et al. 1994).
At least eight fish species feed on live corals, with their feeding strategies ranging from removing mainly live tissue and causing little damage to the skeleton, to abrading or breaking apart colonies in the feeding process, such as during feeding of Arothron meleagris and Pseudobalistes naufragium (Guzmán and Cortes 1989, Glynn 2001). Porites lobata is commonly grazed by the puffer Arothron meleagris (Guzmán and Robertson 1989, Glynn et al. 1994).
In the Eastern Tropical Pacific, Porites lobata was greatly affected by the 1982-83 El Niño event (Guzmán pers. comm.) at Caño Island, Costa Rica, where live cover declined by about 68% (Guzmán et al. 1987). Populations were even more reduced in Cocos Island (to 3%) (Guzmán and Cortes 1992), but had recovered after 20 years (Guzmán and Cortes 2006). High mortalities (95-100%) were also reported in the Galápagos from many sites (e.g., San Cristobal and Santa Cruz), and high partial mortality (<1-18% live tissue remaining) was found at most sites (Glynn 1990, Glynn et al. 1994).
In the Indo-Pacific, this species exhibited moderate bleaching and mortality (10-40%) in the 1998 bleaching event in Palau (Brunno et al. 2001).
Porites is heavily collected for the aquarium trade. In Indonesia, the catch quota for this genus is 55,500 per year; annual collection quota for P. lobata is 3,000 (Terangi Indonesian Coral Reef Foundation, unpublished data).
The genus is not particularly susceptible to bleaching, but is more prone to disease than many other corals. Coral disease has emerged as a serious threat to coral reefs worldwide and is a major cause of reef deterioration (Weil et al. 2006). The numbers of diseases and coral species affected, as well as the distribution of diseases have all increased dramatically within the last decade (Porter et al. 2001, Green and Bruckner 2000, Sutherland et al. 2004, Weil 2004). Coral disease epizootics have resulted in significant losses of coral cover and were implicated in the dramatic decline of acroporids in the Florida Keys (Aronson and Precht 2001, Porter et al. 2001, Patterson et al. 2002). In the Indo-Pacific, disease is also on the rise with disease outbreaks recently reported from the Great Barrier Reef (Willis et al. 2004), Marshall Islands (Jacobson 2006) and the northwestern Hawaiian Islands (Aeby 2006). Increased coral disease levels on the Great Barrier Reef were correlated with increased ocean temperatures (Willis et al. 2007) supporting the prediction that disease levels will be increasing with higher sea surface temperatures. Escalating anthropogenic stressors combined with the threats associated with global climate change of increases in coral disease, frequency and duration of coral bleaching and ocean acidification place coral reefs in the Indo-Pacific at high risk of collapse.
In general, the major threat to corals is global climate change, in particular, temperature extremes leading to bleaching and increased susceptibility to disease, increased severity of ENSO events and storms, and ocean acidification. In addition to global climate change, corals are also threatened by a number of localized threats. Localized threats to corals include fisheries, human development (industry, settlement, tourism, and transportation), changes in native species dynamics (competitors, predators, pathogens and parasites), invasive species (competitors, predators, pathogens and parasites), dynamite fishing, chemical fishing, pollution from agriculture and industry, domestic pollution, sedimentation, and human recreation and tourism activities. The severity of these combined threats to the global population of each individual species is not known.
All corals are listed on CITES Appendix II. Parts of this species distribution fall within several Marine Protected Areas within its range.
Recommended measures for conserving this species include research in taxonomy, population, abundance and trends, ecology and habitat status, threats and resilience to threats, restoration action; identification, establishment and management of new protected areas; expansion of protected areas; recovery management; and disease, pathogen and parasite management. Artificial propagation and techniques such as cryo-preservation of gametes may become important for conserving coral biodiversity.
Having timely access to national-level trade data for CITES analysis reports would be valuable for monitoring trends this species. The species is targeted by collectors for the aquarium trade and fisheries management is required for the species, e.g., Marine Protected Areas, quotas, size limits, etc. Consideration of the suitability of species for aquaria should also be included as part of fisheries management, and population surveys should be carried out to monitor the effects of harvesting.
|Citation:||Sheppard, A., Fenner, D., Edwards, A., Abrar, M. & Ochavillo, D. 2008. Porites lobata. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 10 March 2014.|
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