Contact

Marsha Colbert - Marsha.Colbert@dep.state.fl.us
Biscayne Bay Environmental Center
1277 NE 79th Street CSWY
Miami, FL 33138-4206
(305) 795-3485
(305) 795-3470 FAX
Hours: M-F 9:00-5:00

Description of Site

Biscayne Bay is a shallow, subtropical lagoon along the southeastern coast of Florida. The Bay is a fairly recent geological formation and the average natural depth was historically three to nine feet. Much of this area has been modified and dredged and average depths now range from six feet to ten feet, except in deeper dredged areas and main channels. The Bay is elongated in shape, and located in a north/south trending direction on the southeastern coast of the Florida peninsula. Biscayne Bay Aquatic Preserve consists of two separate areas of the Bay, one occupying the northern part of the Bay (roughly, just south of Cape Florida on the east, and just south of Chicken Key on the west), and the other occupying the southern portion (Card Sound). The two areas are separated by Biscayne National Park, an underwater park which occupies the central portion of the Bay.

The northern part of the preserve is bordered on the east by the barrier islands of Miami Beach, Fisher Island, Virginia Key, and Key Biscayne and on the west by the predominantly residentially developed mainland shore and the Miami central business district. Urban development and the construction of causeways and the Port of Miami have subdivided the northern preserve into eight basins. Over 20% of the North Bay area has been dredged. The deepest areas of the north bay are the borrow pit north of the Julia Tuttle Causeway and the Government Cut Channel which have been dredged to 26-29 feet and 40 feet respectively. Despite the development that has taken place in the northern bay there still exists an abundance of lush seagrass beds and mangrove fringe forests in certain areas.

The southern part of the preserve consists primarily of Card Sound, located between the southeast mainland of Florida and the northern end of Key Largo, in Miami-Dade and Monroe counties. This portion of Biscayne Bay Aquatic Preserve is part of a larger area of protected marine environments. Biscayne National Park is located to the north. John Pennekamp Coral Reef State Park and Florida Keys National Marine Sanctuary are located to the east of Key Largo. Protected upland areas include the Crocodile Lakes National Wildlife Refuge and the Key Largo Hammocks State Botanical Site on Key Largo. The mainland shoreline is primarily undeveloped and is lined with mangroves. On the seaward side of the Sound, access to the offshore areas and water circulation are restricted by the presence of islands (or keys) with few tidal inlets. There is an exposed shallow ridge of limestone adjacent to the western shoreline where water depths are less that six feet at low tide. The submerged ledge extends more than three or four miles form shore and generally supports lush seagrass and hard bottom communities. In contrast to the urbanized northern portion of the preserve, Card Sound has the distinction of being one of the most pristine areas in coastal South Florida.

Established

The Biscayne Bay Aquatic Preserve was established by the Florida Legislature in 1974. The Legislative intent for establishing aquatic preserves is stated in Section 258.36, F.S.: "It is the intent of the Legislature that the state-owned submerged lands in areas which have exceptional biological, aesthetic, and scientific value, as hereinafter described, be set aside forever as aquatic preserves or sanctuaries for the benefit of future generations." This statement along with the special provisions of Section 258.397, F.S. and Chapter 18-18, F.A.C. which together establish the boundaries, management authority, and rules specifically for Biscayne Bay Aquatic Preserve, clearly mark the direction for management of the aquatic preserve.

Location

Counties: Miami-Dade, Monroe
Nearby City: Miami, Florida
Adjacent to U.S. Highway 1

Size

Approximately 69,000 acres of state submerged land

Watershed

Surface water flow into Biscayne Bay is primarily controlled by the system of canals, levees, and control structures constructed as part of the C&SF Project. This network of canals, known as the primary system, is maintained by the SFWMD. Biscayne Bay receives freshwater surface flows from seventeen surface water management basins through twelve major coastal structures. The watershed is composed of the drainage basins east of the Everglades, including portions of southern Broward and northern Monroe counties and is comprised of a marine ecosystem of about 428 square miles and a drainage area of about 938 square miles, including 350 square miles of wetlands.

Habitat

Biscayne Bay supports diverse biological communities including submerged aquatic, coastal wetland, and coastal upland habitats. Submerged aquatic habitats consist of open water communities such as plankton, fishes, seagrasses, and hard-bottom communities. Plankton appears to form the basis of the food chain in northern Biscayne Bay, whereas seagrasses and mangrove detritus provide the primary food source in southern Biscayne Bay. Coastal wetland communities include mangroves and salt marshes. These plants provide habitat for numerous shoreline organisms, protection from erosion or storm damage, and an important source of food in the bay. Coastal upland plant communities consist of hammocks, pinelands, and dune vegetation, and provide vital protection to the Bay from the effects of upland runoff and pollutant loading.

Ecological Importance

The rich fauna found in Biscayne Bay results from the diverse habitats found in the bay. Extensive seagrass beds, mangrove forests, estuarine, and hard-bottom communities are found here. In addition to fish directly important to man, such as snook and red drum, the mangrove and estuarine areas support a diverse collection of other fishes which are links in a food web which carries the rich productivity of the mangrove forests and estuarine zone out to benefit the entire Biscayne Bay ecosystem.

Seagrass habitat is especially prevalent in Biscayne Bay and the corresponding fish fauna is well developed including bonefish, ladyfish, pompano, permit, red drum, spotted sea trout, silver perch, hogfish, nassau grouper, red grouper, black grouper, gag, yellowfin mojarra, and crevalle jack. Grassbeds also serve as a food source for the West Indian manatee and as nursery grounds for several important species of fish and invertebrates.

The fish fauna of Biscayne Bay is large, diverse, and interesting. At least 512 fish species occur in the bay, which is impressive for an area without well developed coral reefs. Along the Florida coast north of Cape Canaveral, fish species are largely those typical of temperate waters, many of which range far north of Florida. The fish species in the Florida Keys are predominantly tropical, many occurring throughout the Caribbean. Biscayne Bay is part of a transition area where fish species of both kinds are well represented. There is some seasonal fluctuation, with tropical species more prevalent in the summer and temperate species partially replacing them in the winter.

An undetermined but very large number of invertebrate species live within Biscayne Bay. Benthic surveys have yielded over 800 species including over 150 species of shrimp, crabs, and lobsters with widely varying ecological requirements in the bay. Many of these species are commercially harvested including blue crab, penaeid shrimp, and sponges. The most common sponges in the hard-bottom community are the loggerhead sponge (Spheciospongia vesparia) and the basket sponge (Ircinia campana). Numerous commercial sponge species also occur in the central and southern portions of the Bay. The importance of Biscayne Bay to juvenile spiny lobster (Panulirus argus) has resulted in a large portion of the bay (roughly from Cape Florida south through Card Sound) to be designated as a Lobster Sanctuary.

Sea turtles that occur in Biscayne Bay are the Atlantic green turtle, the Atlantic hawksbill, the leatherback, the Atlantic ridley, and the loggerhead. Green turtles and loggerheads occur regularly in the bay, whereas hawksbills seem to be less common, there, at least in recent years. Hawksbill nests have been recorded along the outer keys of Biscayne Bay and leatherback nests have been recorded on Miami Beach and Key Biscayne. Green turtles and loggerheads regularly forage within the bay. The predominantly vegetarian green turtle feeds in grassbeds, whereas the more omnivorous loggerhead finds a varied diet of sponges, molluscs, crustaceans, sea urchins and plants in hard bottom communities. Other noteworthy reptiles that are associated with the bay are the American alligator and the American crocodile, an endangered species.

The avifauna of Biscayne Bay is perhaps the most conspicuous of the bay’s wildlife. Many species are permanent residents of the bay, other species migrate through the area, and still others are winter or summer residents. Biscayne Bay is a major stopover in the autumn migration of North American shorebirds. Several species of shorebirds overwinter in Biscayne Bay, making extensive use of shorelines and intertidal areas. The bay has several areas where migratory species roost and forage. Major bird rookeries occur within the bay, including Bird Key and Chicken Key in the central bay, the mangrove shoreline south of Matheson Hammock extending south through Biscayne National Park, in the trees along the shores of Key Biscayne and Virginia Key, the mangrove islands of North Bay just east of Greynolds Park and north of the Sunny Isles Causeway, and mangrove islands in the West Lake area.

Rare / Endangered Species

State listings are taken from the Florida Fish and Wildlife Conservation Commission or as with plants Florida Department of Agriculture.  Federal listings are taken from the United States Fish and Wildlife Service. E= Endangered; T= Threatened; T (s/a)= Threatened due to similarity in appearance; SSC= Species of Special Concern; UR= Under review; n/a= information not available or no designation listed; C=Commercially exploited

Geomorphic Features

Biscayne Bay occupies a bedrock basinal area bounded on the west by the Atlantic Coastal Ridge, composed of Miami Limestone, and the low platform of the Everglades. On the east the basinal depression is delimited by a narrow elongate ridge composed of Key Largo Limestone. This ridge underlies Miami Beach and Key Biscayne and rises above sea level to the south forming the Florida Keys. During the Holocene rise in sea level, the depression that is now the bay began to fill with sea water. Unlike many estuaries in the eastern United States, Biscayne Bay is not a drowned river valley and has no rivers that bring in significant amounts of sediments eroded from land. Natural sedimentary inputs into this system are primarily quartz sand carried by longshore coastal transport, carbonate shell sand, carbonate mud and organic material that is derived from organisms within the bay or generated by coastal processes.

Archaeological Features

The maritime environment has played a very important role in the historic and cultural makeup of this geographic area. From the ancient to the modern, most interests in the area have been turned toward the hospitable climate and the commerce of the seas.

The earliest human residents were the various tribes or clans of American Indians that traversed the nearshore waters and rivers of the region in dugout canoes. Evidence suggests that these tribes settled near the coast to exploit the abundant fish, turtles and mollusks. Radiocarbon dating of archaeological remains indicates that the permanent settlement of the Biscayne Bay area dates back to at least 2,000 B.C., and that there were inhabitants in this area as early as 8,000 B.C.

The Tequesta tribe occupied the area of Biscayne Bay when the first Europeans explored the American coast. The Calusa Indians from the west coast were believed to have interacted, often violently, with the Tequestas. Other smaller tribes, principally the Matecumbes, also defended small settlements in the Keys.

The native Indians' occupation of the area was short lived after the Spanish made landfall in the west. Early explorers included Ponce De Leon who navigated the peninsula in the early 1500's and was reported to have sailed into Chequescha Bay (Biscayne Bay) in 1513. Spanish domination of the state lasted until 1763 when Florida was traded to the English for the city of Havana which the English had captured a year before. It was traded back to the Spanish in exchange for the Bahama Islands and was later ceded to the fledgling government of the newly founded United States in a treaty agreement in 1821.

Disease, warfare, and capture decimated Indian populations in less than 200 years. There exists a paucity of undisturbed coastal archaeological sites left by the early Indians of the area. These include midden and burial grounds along the nearshore banks of Biscayne Bay.

Uses

Biscayne Bay’s beauty and utility invites a diversity of recreational and commercial in-water activities, including power boating, sail boating, catamaraning, canoeing, sculling, water skiing, jet skiing, hang gliding, swimming, windsurfing, snorkeling, diving, and fishing.

The Bay is also important navigationally as part of the ICW and home to the Port of Miami, one of the busiest cargo and passenger ports in the world. The commercial Chalk’s airline located on the south side of Watson Island has used the Miami Shipping Channel for landing and takeoff of their waterborne craft since the 1920's.

The Bay provides for a variety of educational and research activities. Several marine science and education facilities utilize the Bay and include: University of Miami School of Marine and Atmospheric Sciences (RSMAS), Florida International University, Barry University, N.O.A.A., the Southeast Fisheries Laboratory, and the Miami Seaquarium. On the secondary level, MAST academy is a local magnet school located on Virginia Key and is dedicated to students interested in marine science. In addition to these institutions, several governmental agencies as well as scientists from remote locations conduct research and education programs pertaining to Biscayne Bay.

Management Status

Biscayne Bay Aquatic Preserve consists primarily of state submerged lands and islands and the water column over such lands. Those submerged lands within the boundaries of the preserve that are privately owned or leased or which have been deeded to the County or municipalities are also part of the preserve. The preserve has been designated as an Outstanding Florida Water, Class III.

The preserve is managed by the Florida Department of Environmental Protection, Office of Coastal and Aquatic Managed Areas. Major management issues involve the protection of the resources within the preserve in accordance with F.S. 258.397 and F.A.C. 18-18. In addition to monitoring and reviewing projects which may impact the resources of the preserve, efforts are also directed towards research and education. Considerable efforts are directed toward restoration projects within the preserve, with the recent restoration at Bill Baggs State Park at Cape Florida and the county’s vigorous artificial reef program being leading examples. Monitoring activities within the preserve include an extensive water quality monitoring program administered by SFWMD and DERM and a recent project conducted jointly by the DEP and NOAA monitored sediments throughout the Bay.

References

deSylva, D. P. 1984. A Bibliography and Index of the Biscayne Bay Ecosystem. University of Miami School of Marine and Atmospheric Science, 91 pp.

Florida Department of Natural Resources. 1991. Management Plan (cabinet draft, not adopted) For Biscayne Bay Aquatic Preserve Card Sound. Division of State Lands, 180 pp.

Metropolitan Dade County Board of County Commissioners. 1986. Environmental Resource Management Department and Metropolitan Dade County Planning Department. 1986. Biscayne Bay Aquatic Preserve Management Plan (draft, not adopted). Metropolitan Dade County, Miami, Florida, 348 pp.

South Florida Water Management District. 1995. Surface Water Improvement and Management Plan for Biscayne Bay. Planning Department, West Palm Beach, Florida.