Oculina varicosa 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Cnidaria Anthozoa Scleractinia Oculinidae

Scientific Name: Oculina varicosa (Lesueur, 1821)
Common Name(s):
English Large Ivory Coral

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2ac ver 3.1
Year Published: 2008
Date Assessed: 2008-01-01
Assessor(s): Aronson, R., Bruckner, A., Moore, J., Precht, B. & E. Weil
Reviewer(s): Livingstone, S., Polidoro, B. & Smith, J. (Global Marine Species Assessment)
This species is listed as Vulnerable as the species is estimated to have undergone a decline of greater than 30% across the range due to the effects of bottom-tending fishing gear. Deep-water populations off the coast of Florida to North Carolina (Oculina Banks) have undergone declines exceeding 50% since the 1970s, although there is no evidence of extensive declines throughout the range, including shallow-water populations and deeper populations in the Gulf of Mexico. There is no evidence of recovery within Oculina Banks, and although recent surveys have documented further damage there is no indication that this has occurred elsewhere.

Geographic Range [top]

Range Description:This species occurs in the Caribbean, much of the Gulf of Mexico (excluding the Flower Gardens), Florida, and the Bahamas. The northernmost record is off the coast of North Carolina at Cape Hatteras (Reed, 1980). The presence of this species in Bermuda requires confirmation.
Countries occurrence:
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; Atlantic – northwest
Additional data:
Lower depth limit (metres):152
Upper depth limit (metres):3
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species is relatively common throughout its range, and may form dense monospecific assemblages and bioherms.

There is no species specific population information available for this species. However, there is evidence that habitat quality has declined.

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 generation length estimates.
For further information about this species, see Corals_SupportingDoc.pdf.
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Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Colonies are found to depths of 152 m depth on limestone rubble, low-relief limestone outcrops, high-relief, steeply sloping prominences, and soft-bottom sloping habitats. Colonies are semi-isolated, patchy and low-growing in shallow water, or they form larger, massive coalescing aggregates (thickets or coppices) with substantial topographic relief in 50-100 m depth. In shallow waters (2-30m) the form is zooxanthellate, inhabiting limestone ledges. In deeper waters, an azooxanthellate form is known from the shelf edge off eastern Florida, USA from Ft. Pierce to Daytona (Reed 1980, 1983, 2002; Brooke and Young 2003).

The arbuscula form is reported to be tolerant of a wide temperature range and varying light levels. It occurs both in well lit areas and darker crevices from shallow subtidal at least to 25 m depth, but most common from 5-6 m depth. In shallow water it is found on jetties, submerged ships, and other artificial substrates. It also occurs on vertical surfaces and under overhangs. High abundances of macroalgae in shallow water appear to limit its occurrence (Miller 1995).

Threats [top]

Major Threat(s): The major threat to this species is mechanical damage associated with fishing gear, including dredges, bottom long lines, trawl nets and anchors. There have been major losses of this coral off the east coast of Florida to North Carolina in an area known as the Oculina Banks, with over 50% of the population being decimated due to bottom-trawling (Koenig et al. 2005,Reed, in press). The species is not reported to be affected by disease and bleaching. There may be minor impacts associated with bio-eroding organisms such as endolithic sponges.

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.

Conservation Actions [top]

Conservation Actions: Listed on CITES Appendix II. Identified as a Species of Concern in the US under the Endangered Species Act; this does not provide any legal protection, but is designed to raise awareness about this species and promote proactive conservation efforts. In US waters, it is illegal to harvest corals for commercial purposes. The largest known population is in an area known as Oculina Banks has been protected as the Oculina Habitat Area of Particular Concern (HAPC) since 1984, prohibiting trawling, dredging, bottom longlines and anchoring. Legislation was enacted in 2000 for expansion of the Oculina HAPC to 1,029 km². The United States Coast Guard has been charged with surveillance and enforcement of the ban on bottom fishing and trawling. The primary difficulties in protecting these reefs and other deep-water Marine Protected Areas are their remoteness and time required to engage an enforcement vessel (Reed 2002). Consequently, some illegal fishing continues to occur that continues to impact remaining populations.

Small-scale restoration attempts have been undertaken in the Oculina reserve with varying success.

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 varicosa. The IUCN Red List of Threatened Species 2008: e.T133165A3610094. . Downloaded on 20 May 2018.
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