Abstract

Petroleum platforms in the U.S. Gulf of Mexico (U.S. GOM) are important habitat for fishes and support regional fisheries. However, drivers of the regional distribution of fishes associated with these artificial habitats are not fully understood. To address this, we conducted 114 submersible-rotating drop-camera and water quality sonde surveys at 54 platforms throughout the U.S. GOM. We then fit two sets of binomial generalized additive mixed models (GAMMs) integrating environmental and structural predictors to encounter/non-encounter data for 17 fish species, so as to understand their horizontal and vertical distribution patterns around platforms. Significant predictors for horizontal distribution included distance from shore (Bermuda Chub Kyphosus sectatrix, Greater Amberjack Seriola dumerili, Vermilion Snapper Rhomboplites aurorubens), salinity (Bermuda Chub, Red Snapper Lutjanus campechanus), the number of platforms within five kilometers (Blue Runner Caranx crysos, Crevalle Jack Caranx hippos), and dissolved oxygen concentration (Red Snapper). Significant predictors for vertical distribution included salinity (Atlantic Spadefish Chaetodipterus faber, Bermuda Chub, Greater Amberjack, Red Snapper, Vermilion Snapper), dissolved oxygen concentration (Greater Amberjack, Red Snapper), and seafloor depth (Red Snapper). However, the majority of the study species were not influenced by the predictors included in the horizontal (11/17 species) and vertical distribution (12/17 species) GAMMs. Thus, many U.S. GOM fishes were found to associate with platforms over a relatively wide range of environmental conditions and platform characteristics. This suggests that association with the physical habitat may be more important than the optimal environmental conditions and specific platform characteristics for these fishes.

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