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
HABITAT AND DISTRIBUTION
Oculina varicosa occurs from
the east Florida coast to North Carolina, Bermuda and the West Indies (Reed et al 1982).
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.
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.
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.
Reef temperatures recorded for Oculina varicosa off Fort Pierce, Florida
ranged from 7 - 31°C and averaged 15 - 25°C.
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.
O. varicosa feeds on plankton and tiny fish. It may also
suspension feed using mucous strands.
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).
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.
Oculina varicosa provides nursery and habitat for commercially and
recreationally important fish including grouper and snapper.
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
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Page last updated: July 25, 2001