Nearshore and Midshelf Reefs

Geologically, the rock formations upon which reef communities develop are known as the Anastasia formation which form the backbone of the Atlantic coastal ridge (Stauble and McNeill 1985). This limestone formation is the result of several Pleistocene accretion events and is named for Anastasia Island were it was first described (Puri and Vernon 1964). Portions of the formation are exposed beneath the sea surface resulting in an extensive reef system.

Florida's reefs are not dominated by a single phylogenetic group, making specific classification difficult. Of the various types of reef, the coral reef, which is dominated by hermatypic corals, has the most structural complexity. These formations form the most popular image associated with the term reef. Coral reefs are best developed in the U.S., primarily within the Florida Reef Tract (primarily in Monroe County). Most of the Florida Keys' coral reefs are well known due to the clarity of the water and the popularity of SCUBA diving. The ecology of coral reefs is described in some detail by Jaap (1984). The coral reefs in the Florida Keys are a trust resource of the National Oceanic and Atmospheric Administration (NOAA) and are protected as part of the Florida Keys National Marine Sanctuary. A special set of management plans has been developed for this resource (NOAA 1996).

Farther north, through Miami-Dade and Broward (Figure 1) counties on the east coast and Collier County on the west coast, water clarity and temperature declines as do reef-building corals. Although the range of hermatypic corals may extend as far north as Stuart on the east coast, the solid substrate is increasingly populated by soft corals (gorgonians). North of Stuart, the warm waters of the Gulf Stream are farther offshore, soft corals are fewer and hard bottom communities are more prevalent. Hard bottom communities are populated by sponges, small (ahermatypic) hard corals, tunicates, bryozoans, algae, and sabellariid worms. Such communities are typical of Florida's West coast from Collier County north; however, few studies have been completed on sabellariid worms reefs on Florida's west coast. Consequently, most of the reef ecology referenced in this recovery plan has been obtained from research performed on the east coast.

Sabellariid worms can dominate the reef community and form a unique reef type known as worm reef. These reefs are most often formed in high energy surf zones between Martin and Brevard counties (Kirtley and Tanner 1968), thus may provide shoreline protection by reducing wave energy on the beach. Such reefs are composed of loosely cemented sand particles which are held together by a mucus secreted by the worms when building their casing. Sabellariid worm colonies provide habitat for over 325 species of invertebrates (Nelson 1989). Nelson and Demetraides (1992) found that, seasonally, abundances of isopod and amphipod species can be as high as 50,000 and 22,000 individuals per square meter, respectively. Algal species can also dominate some reef areas. Offshore of central Florida at Vero Beach, 109 algal species were identified by Juett et al. (1976).

Taken from: U.S. Fish and Wildlife Service. 1999. South Florida Multi-Species Recovery Plan. Atlanta, Georgia. Pp. 624, 626.

Listed Species Occurring in Nearshore and Midshelf Reef Habitat

  • West Indian Manatee
  • Piping Plover
  • Roseate Tern
  • Loggerhead Sea Turtle
  • Leatherback Sea Turtle
  • Kemp's Ridley Sea Turtle
  • Hawksbill Sea Turtle
  • Green Sea Turtle