Florida Sea Grant Extension in Collier County

Welcome to the Collier County Sea Grant Extension Blog

This blog is an opportunity for me to share with you my extension outreach efforts and useful information to make you a more informed coastal citizen. If you have any questions about what you see, feel free to contact me at fluech@ufl.edu.

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Tuesday, August 9, 2011

Common Coral Species Associated with Southwest Florida's Hardbottom Communities

A red grouper over natural hardbottom

Much of the shallow continental shelf off Southwest Florida consists of unconsolidated sand and shell rubble substrates overlying a limestone baserock. Isolated tracks of natural hardbottom ledges and rock outcroppings as well as artificial reefs are interspersed throughout the region providing suitable substrate for coral colonization. Unlike many of the corals found in the Florida Keys, corals that are associated with Southwest Florida's hardbottom communities, do not construct living reefs. They typically form isolated colonies.

These corals and other associated biota including macroalgae, tunicates,  sponges, hydroids, and bryozoans contribute to the productivity of Southwest Florida's unique hardbottom communities. They help provide structure, protection, and food  sources for a variety of fish assemblages and invertebrates including recreational and commercially important species such as red grouper (Epinephelus morio ), gag grouper (Mycteroperca microlepis ),  and Florida stone crab (Menippe mercenaria ).
Examples of hard coral species typically found on natural and artificial hardbottom communities in Southwest Florida include Knobby Star Coral (Solenastrea hyades), Starlet corals (Siderastrea spp), Robust Ivory Tree Coral (Oculina robusta), Tube Coral (Cladocora arbuscula) and Hidden Cup Coral (Phylangia americana).
Knobby Star Coral is one of the most common hard corals found on nearshore natural hardbottoms in Southwest Florida. Their colonies have lobated heads with irregular bulges on the surface, and range from a few inches up to two feet in length. Colors range from yellow-brown to cream to tan. The polyps can often be seen feeding during the day.
Starlet Coral colonies form irregular rounded domes and mounds and vary in color from golden-brown and brown to gray. Colonies can range from a few inches to several feet.

Robust Ivory Tree Coral colonies are less common than the star and starlet corals. Coral colonies form large busy, tree-like structures with a thick base. Colonies can reach close to three feet in length and tend to be yellowish brown.

Tube Coral colonies form small densely branching clumps with fine ridges running their length. Colonies are usually only several inches and range from tan to golden brown to dark brown in color.

Hidden Cup Coral colonies form small encrusting groups of polyps less than an inch wide.They are found on the undersides of ledges or encrusted onto the surface of outcroppings and typically yellowish to reddish brown in color.

Examples of soft corals found in Southwest Florida include the Colorful Sea Whip  (Leptogorgia virgulata) and the Regal Sea Fan (Leptogorgia hebes). Unlike the hard corals, they exhibit a variety of vibrant colors.

Colorful Sea Whips form long straight, stiff, moderately-branched stalks. They can range from yellow to orange to lavender or purple. Their highly visible polyps are translucent white.

Colonies of Regal Sea Fans are characterized by being flat and thickly branched, and are generally aligned a single plain. Like the Colorful Sea Whip, they display a variety of colors ranging from red and orange to reddish purple and purple.

Dupont, J.M. 2009. Ledges and Artificial Reefs on the Inner Central West Florida Shelf
Dissertation , University of South Florida
Humann, P. 1993. Reef Coral Identification: Florida Caribbean Bahamas, Including Marine Plants.
Jaap WC.1984. The ecology of the South Florida coral reefs: a community profile.
Minerals Management Service MMS 84–0038. 138 ppEcological Dynamics of Livebottom

Although present, the diversity of stony and soft corals found off Southwest Florida' coast is severely limited compared to what is found on Florida's east coast. Seasonal temperature fluctuations and high turbidity rates characteristic of Gulf waters provide a less than hospitable environment for most corals. Yet, several hardy species do inhabit the region.

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