Stony coral (Milleporidae and Scleractinia) communities in the eastern Gulf of Mexico: a synopsis with insights from the Hourglass collections

Abstract

The eastern Gulf of Mexico is a complex mosaic of coral reefs and epibenthic communities. Although it is a large area of approximately 225,000 km2, only a small portion sustains viable coral reefs. In the lower margins of the eastern Gulf of Mexico (Key West to Dry Tortugas, 24°33'N), the coral reef communities are speciose and very similar to Caribbean coral reefs. Controlling factors influencing the distribution of the hydrozoan Millepora and Scleractinian species include climate, the lack of a consistent current system to support larval transport, and stochastic disturbances, such as red tide-harmful algal blooms, hurricanes, and winter frontal passages. In the eastern Gulf of Mexico region north of 26°N (Naples), the fauna is more eurytopic; characteristic species inhabiting the rocky hard bottom include Cladocora arbuscula (Lesueur, 1820), Siderastrea radians (Pallas, 1766), Solenastrea hyades (Dana, 1846), Manicina areolata (Linnaeus, 1758), and Isophyllia sinuosa (Ellis and Solander, 1786). Isolated locations, such as the Florida Middle Grounds and Pulley Ridge, sustain the more reef-dwelling-stenotopic species: Leptoseris cuccullata (Ellis and Solander, 1786); Dichocoenia stokesi Milne-Edwards and Haime, 1848; and Meandrina meandrites (Linnaeus, 1758). The present study focuses on the Hourglass collection of Scleractinian coral samples collected from August 1965 through November 1967 in the eastern Gulf of Mexico offshore of Tampa Bay (27°35'N) and Sanibel Island (26°24'N), from 6 to 73 m depths.