Abstract

Benthic community composition was characterized at Southern Bank (27? 26’ 30” N, 96? 31’ 30” W), a 1.0 sq. km, mid-continental shelf relic coral-algal reef off the coast of South Texas that rises from a regional depth of 82 m to 59 m below the sea surface. Remotely operated vehicle (ROV) surveys were conducted in September 2014 to collect video and biological specimens of the benthic invertebrate community, with particular focus on antipatharians, scleractinians and octocorals. Percent cover and abundance were estimated from 50 randomly extracted frame grabs of the sea floor. Video identifications of coral species were assisted by simultaneous collections of specimens and subsequent morphological and genetic analyses. Algae was the dominant biotic cover (39.1%). Among macrofauna, encrusting sponges (46.0%), antipatharians (23.2%), and crinoids (6.7%) had the highest substrate cover. Coral cover was primarily antipatharians (76.7%; Stichopathes spp. [47%], Antipathes furcata [23%], and Antipathes atlantica [22%]), followed by scleractinians (22.6%; Madracis brueggmani [84%] and Agaricia fragilis [10%]), and octocorals (1.7%). The most abundant corals were Stichopathes spp. (2.0 ind./m2) and Antipathes furcata (0.7 ind./m2). Benthic abundance data was georeferenced and correlated to bank microtopography in order to create a habitat suitability map which can be used to predict biodiversity at other the mesophotic banks in South Texas.

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