|Scientific Name:||Oculina diffusa (Lamarck, 1816)|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Aronson, R., Bruckner, A., Moore, J., Precht, B. & E. Weil|
|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 locally abundant throughout its range and threats operating are not known to be resulting in any significant population declines. Therefore, the estimated habitat loss of 10% 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 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:||This species occurs in the Caribbean, Gulf of Mexico (but not in the Flower Gardens), Florida, the Bahamas, and Bermuda. It is unclear whether descriptions of this coral in the Gulf of Mexico are actually of this species and not of O. varicosa.|
Native:Anguilla; Antigua and Barbuda; Bahamas; Barbados; Belize; Bermuda; Bonaire, Sint Eustatius and Saba (Saba, Sint Eustatius); Cayman Islands; Colombia; Costa Rica; Cuba; Curaçao; Dominica; Dominican Republic; Grenada; Guadeloupe; Haiti; Honduras; Jamaica; Mexico; Montserrat; Nicaragua; Panama; Saint Barthélemy; Saint Kitts and Nevis; Saint Lucia; Saint Martin (French part); Saint Vincent and the Grenadines; Sint Maarten (Dutch part); Trinidad and Tobago; Turks and Caicos Islands; United States; United States Minor Outlying Islands; Venezuela, Bolivarian Republic of; Virgin Islands, British
|FAO Marine Fishing Areas:|
Atlantic – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species is widespread in soft-bottom habitats, and may be locally abundant.|
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. See the supplementary material for further details on population decline and generation length estimates.
|Current Population Trend:||Stable|
|Habitat and Ecology:||This species occurs predominantly in soft-bottom habitats, including seagrass beds, branching coral thickets, sloping fore reef and back reef environments, in deeper lagoon habitats, and in the roots and sediments of mangrove islands. Found from 0.5-30 m, but most abundant from 1-15 m. This species is generally resistant to high rates of sedimentation, salinity and temperature changes.|
A major threat affecting this species could be bottom-tending fishing gear (trawls, traps, longlines). Not reported to be affected by bleaching or disease.
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.
Coral disease has emerged as a serious threat to coral reefs worldwide and 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 GBR 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.
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.
Listed on CITES Appendix II. In the US, it is present in many MPAs, including Florida Keys National Marine Sanctuary, Biscayne N.P. and Dry Tortugas National Park. In US waters, it is illegal to harvest corals for commercial purposes.
There is a need to evaluate the impacts associated with trawls and fishtraps in habitats where this coral occurs. (Aronson, R., Precht, W., Moore, J., Weil, E., and Bruckner, A. pers. comm.)
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.
|Citation:||Aronson, R., Bruckner, A., Moore, J., Precht, B. & E. Weil. 2008. Oculina diffusa. The IUCN Red List of Threatened Species 2008: e.T133212A3634319.Downloaded on 17 August 2018.|
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