Smithsonian Marine Station at Fort Pierce

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Colony of Oculina varicosa. Photo courtesy of: J. Reed, Harbor Branch Oceanographic Institution.

Species Name: Oculina varicosa Lesueur, 1821
Common Name: Ivory Tree Coral
Synonymy: None
  1. TAXONOMY

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Animalia Cnidaria Anthozoa Scleractinia Oculinidae Oculina

    Species Description

    In shallow waters (2 - 40 m), Oculina varicosa often occurs as a semi-isolated, low-growing colony, patchily distributed on coquinoid reef. However, in deeper water (70 -100 m) it can occur as a massive, coalescing aggregate having substantial topographical relief. Colors range from yellow-brown to lavender.

    Potentially Misidentified Species

    Oculina diffusa, Oculina arbuscula, Oculina valenciennesi

  2. HABITAT AND DISTRIBUTION

    Regional Occurrence

    Oculina varicosa occurs from the east Florida coast to North Carolina, Bermuda and the West Indies (Reed et al 1982).

    IRL Distribution

    Oculina varicosa occurs sparsely in the Indian River Lagoon and on ledges in intracoastal waterways. O. varicosa occurs abundantly on shallow (6 m) near-shore reefs and on shelf edge banks (80 m) off east central Florida.

  3. LIFE HISTORY AND POPULATION BIOLOGY

    Age, Size, Lifespan

    Size range in Oculina varicosa found in shallow water is from 10 - 25 cm, with an average size of 15 cm. Deep water specimens can range from 25 - 150 cm; with a typical size of 100 cm.

    Growth rates are apparently somewhat higher in deeper water than in shallow water. Growth for this species at 6m depth was 11.3 mm per year; however, at 80 m depth, growth rate of Oculina varicosa was 16.1 mm per year. Based on growth rates of 16 mm/yr, large colonies of Oculina varicosa could exceed 100 years of age.

    Embryology

    Egg development time of Oculina varicosa in the laboratory is approximately 12 hours. The planula larva is most likely lecithotrophic and takes 18 - 22 days for development at 16°C, in the laboratory.

  4. PHYSICAL TOLERANCES

    Temperature

    Reef temperatures recorded for Oculina varicosa off Fort Pierce, Florida ranged from 7 - 31°C and averaged 15 - 25°C.

    Salinity

    In the Indian River Lagoon, recorded salinities ranged from 15 - 36.5 ppt. Off Fort Pierce, Florida, reef salinities for this species ranged from 28 - 36.4 ppt.

  5. COMMUNITY ECOLOGY

    Trophic Mode

    O. varicosa feeds on plankton and tiny fish. It may also suspension feed using mucous strands.

    Habitat

    Oculina varicosa grows on low and medium relief limestone ledges (0.5 - 3.0 m) and on high relief shelf edge pinnacles (25 m relief). Benthic depth range for O. varicosa is 3.0 - 150.0 meters. Oculina varicosa can withstand moderate wave exposure on near-shore reefs (3.0 - 5.0 m deep).

  6. ADDITIONAL INFORMATION

    Special Status

    Habitat Structure

    Benefit in the IRL

    Oculina varicosa provides habitat for a high diversity of invertebrates including crustaceans (Reed et al 1982) , mollusks (Reed & Mikkelsen 1987), fish, annelids and sipunculan worms.

    Economic Importance

    Oculina varicosa provides nursery and habitat for commercially and recreationally important fish including grouper and snapper.

  7. REFERENCES

    Reed JK. 1980. Distribution and structure of deep-water Oculina varicosa coral reefs off central eastern Florida. Bull Mar Sci 30: 667-677.

    Reed JK, Gore RH, Scotto LE, Wilson KA. 1982. Community composition, structure, areal and trophic relationships of decapods associated with shallow-and deep-water Oculina varicosa coral reefs: studies on decapod Crustacea from the Indian River region of Florida, XXIV. Bull Mar Sci 32: 761-786.

    Reed JK, Mikkelsen PM. 1987. The molluscan community associated with the scleractinian coral Oculina varicosa. Bull Mar Sci 40: 99-131.

Report by: J. Dineen, Smithsonian Marine Station
with thanks to J. Reed, HBOI
Submit additional information, photos or comments to
irl_webmaster@si.edu
Page last updated: July 25, 2001

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