Abstract

There are many different types of natural reefs in the northwestern Gulf of Mexico (GOM), which accommodate di-verse reef-associated species. In addition to natural reefs, oil and gas platforms function as artificial reefs and almost 250 species of reefs associated fishes have been observed at these structures. Characterizing fish communities is challenging in these complex marine habitats due to both the large vertical relief of platforms and the complicated morphology of natural reefs. A remotely operated vehicle (ROV) based methodology will be tested for utility to rapidly characterize the assem-blages of fishes associated with platforms and natural reefs in the northwestern GOM. Depth-interval-transects (DITs) will be conducted to document fish distributions and community structures at oil and gas platforms. On natural reefs, both DITs and the line transects will be carried out to characterize fish distributions and structures. Video obtained with the ROV will be analyzed for species composition, abundance and habitat complexity around platforms and on natural reefs. Qualitative acoustical camera imagery will also be acquired with a BlueView 2D® imaging sonar mounted on the ROV. Fish can be detected and measured with the Blueview while video data are being collected. Since Blueview has a larger effective view-ing range, data from video and the sonar will be combined to maximize the amount of biological information attainable dur-ing our surveys. Preliminary surveys on Bright and Sidner Banks demonstrate that the ROV provided a great deal of useful information about fish community and habitat information on natural reefs.

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