|Scientific Name:||Porites arnaudi|
|Species Authority:||Reyes-Bonilla and Carricart-Ganivet 2000|
|Red List Category & Criteria:||Least Concern 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)|
In the Eastern Tropical Pacific region, this species is poorly known, with little information on population trends at the two locations where its presence has been confirmed. In the central and south Pacific, this species is widespread and common within its range. However, it is particularly susceptible to disease and is harvested for the aquarium trade, and extensive reduction of coral reef habitat due to a combination of threats. Specific population trends are unknown, but population reduction can be inferred from declines in habitat quality based on the combined estimates of both destroyed reefs and reefs at the critical stage of degradation within its range (Wilkinson 2004). Its threat susceptibility increases the likelihood of being lost within one generation in the future from reefs at a critical stage. Therefore, the estimated habitat degradation and loss of 4% over three generation lengths (30 years) is the best inference of population reduction. This does not meet the threshold of a threat category, and this species is Least Concern. 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:||Porites arnaudi was regarded as an endemic species within the Eastern Tropical Pacific (ETP) region, but the species is now also known to occur throughout the central south Pacific. In the ETP, this species is primarily found near the Revillagigedo Islands and Clipperton Atoll.|
Native:American Samoa (American Samoa); Cook Islands; Fiji; French Polynesia; Guadeloupe; Kiribati; Mexico; Niue; Samoa; Tokelau; Tonga; Tuvalu; United States Minor Outlying Islands; Wallis and Futuna
|FAO Marine Fishing Areas:||
Pacific – eastern central; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
This species is common in the south central Pacific.
In the Eastern Tropical Pacific, Reyes-Bonilla (2003) report Porites arnaudi as a rare species (i.e., found in less than 20% of the reef) but sometimes locally abundant at the Revillagigedo Islands. At Clipperton Atoll, this coral may be prevalent on some upper seaward slopes (Glynn et al. 1996). It was not abundant at the southeast site, but comprised to 7.4% mean cover at 16 m (Glynn et al. 1996).
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 particularly susceptible to bleaching, disease, and other threats and therefore population decline is based on both the percentage of destroyed reefs and critical reefs that are likely to be destroyed within 20 years (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 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 found on upper reef slopes or rocky foreshores exposed to strong wave action. Porites arnaudi is distributed at depths from 7 to 37 m, especially in steep rocky slopes or rocky foreshores exposed to strong wave action (Glynn et al. 1996; Reyes-Bonilla and Carricart-Gavinet 2000). P. arnaudi forms tiered plates that frequently overgrow other species, especially P. lobata, Pavona varians and Psammocora superficialis (Glynn et al. 1996; Reyes-Bonilla and Carricart-Gavinet 2000 ). Reyes-Bonilla and Carricart-Gavinet (2000) suggested that the fishes Arothron meleagris and Melichthys niger may feed on P. arnaudi.|
Porites species are heavily collected for the aquarium trade.
The unbranching species in this 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 arnaudi. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 20 April 2014.|
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