OCS Study BOEM 2017-024 Deepwater Reconnaissance of Potentially Sensitive Biological Features Surrounding Shelf-Edge Topographical Banks in the Northern Gulf of Mexico U.S. Department of the Interior Bureau of Ocean Energy Management Gulf of Mexico OCS Region OCS Study BOEM 2017-024 Deepwater Reconnaissance of Potentially Sensitive Biological Features Surrounding Shelf-Edge Topographical Banks in the Northern Gulf of Mexico Author Paul Sammarco Prepared under BOEM Contract M11AC00005 by Louisiana Universities Marine Consortium 8124 Highway 56 Baton Rouge, LA 70344-2110 Published by U.S. Department of the Interior New Orleans, LA Bureau of Ocean Energy Management February 2017 Gulf of Mexico OCS Region DISCLAIMER This report was prepared under contract between the Bureau of Ocean Energy Management (BOEM) and Louisiana Universities Marine Consortium (LUMCON). This report has been technically reviewed by BOEM, and it has been approved for publication. Approval does not necessarily signify that the contents reflect the views and policies of BOEM, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. REPORT AVAILABILITY To download a PDF file of this Gulf of Mexico OCS Region report, go to the U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program Information System website and search on OCS Study BOEM 2017-024. This report can be viewed at select Federal Depository Libraries. It can also be obtained from the National Technical Information Service; the contact information is below. U.S. Department of Commerce National Technical Information Service 5301 Shawnee Rd. Springfield, Virginia 22312 Phone: (703) 605-6000, 1(800)553-6847 Fax: (703) 605-6900 Website: http://www.ntis.gov/ CITATION Sammarco, Paul W. 2016. Deepwater reconnaissance of potentially sensitive biological features surrounding shelf-edge topographic banks in the northern Gulf of Mexico. US Dept. of the Interior, Bureau of Ocean Energy Management, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study BOEM 2017-024. 109 p. Cover photo by L. Horn and G. Taylor. © 2016 NOAA Flower Garden Banks National Marine Sanctuary, Galveston, TX. Used with permission. All rights reserved. iii ACKNOWLEDGEMENTS Assistance in the lab and the field was offered by many, and we are grateful for their help. A. Kuba, R.J. Eckert, and K. McGraw were all instrumental in the processing of ROV photographs and data analysis and making a significant contribution to the project in both the lab and the field. Valuable field assistance was offered by (in alphabetical order): J. Baloch, V. Cardona, J. Crouch, K. Eager, J. Embesi, M. Evans, M. Genazzio, B. Gonzales, K. Huchton, C. Isom, A. Kuba, D. Loughmiller, M. McCoin, C. Moore, B. Mayberry, S. Morgan, M. Nannen, M. Scott, A. Sterne, T. Sterne, M. Stout, O. Tobacia, and M. Weekly. Excellent support was also offered at sea by the competent crew of the R/V Manta (NOAA Flower Garden Banks National Marine Sanctuary): J. O’Hern, M. Perry, M. Petry, A.J. Ruffer, M. Shetler, T. Thompson, and D. Walker. H. Hebert, and B. Benoit offered their talented assistance with graphics and computing, respectively. M. Belter and other members of the Bureau of Ocean Energy Management (BOEM) and the Bureau of Safety and Environmental Enforcement (BSEE) offered helpful comments on the manuscript. Study collaboration and funding were provided by the U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program, Washington, DC under Agreement M11AC00005 and funded in part through Inter- Agency Agreement Number M11PG00039 with the National Oceanic and Atmospheric Administration. We are grateful to all. CONTRIBUTING AUTHORS Daniel Beltz, Louisiana Universities Marine Consortium (LUMCON) Emma L. Hickerson, NOAA Flower Garden Banks National Marine Sanctuary (NOAA- FGBNMS), Galveston, Texas Lance Horn, Underseas Vehicle Program, University of North Carolina at Wilmington (UNCW), North Carolina Marissa Nuttall, NOAA-FGBNMS George P. Schmahl, NOAA-FGBNMS Glen Taylor, Underseas Vehicle Program, UNCW iv CONTENTS ACKNOWLEDGEMENTS ............................................................................................................................ iv CONTRIBUTING AUTHORS ....................................................................................................................... iv LIST OF FIGURES ........................................................................................................................................ ii LIST OF TABLES ......................................................................................................................................... iv ABBREVIATIONS and ACRONYMS ............................................................................................................ v 1. INTRODUCTION .................................................................................................................................. 1 1.1 Purpose ......................................................................................................................................... 1 1.2 Comparative Relief on Mesophotic Reefs and Banks in the North-Central Gulf, and Their Geographic Patterns ................................................................................................................................. 1 1.2.1 General Background ............................................................................................................. 1 1.2.2 Importance of Hard Bottom ................................................................................................... 2 1.2.3 Importance of Relief .............................................................................................................. 2 1.2.4 Overall Objectives ................................................................................................................. 3 1.3.4 Disturbances to Offshore Banks ........................................................................................... 6 1.2 Relationship between Relief and Species Richness, Including Geographic Patterns .................. 8 1.4.1 Background on Banks of the Northern Gulf .......................................................................... 8 1.4.2 Importance of Hard Bottom ................................................................................................... 9 1.4.3 Relationship between Relief and Benthic Biodiversity .......................................................... 9 1.4.4 Disturbances to Banks in the Northern Gulf .......................................................................... 9 1.4.5 Quantifying Relief and Biodiversity on Offshore Banks, Including Geographic Patterns .... 10 1.5 Team Participants ....................................................................................................................... 11 1.6 Duration ....................................................................................................................................... 11 2. MATERIALS AND METHODS ........................................................................................................... 12 2.1 Comparative Relief on Banks, Including Geographic Patterns ................................................... 12 2.1.1 Study Sites .......................................................................................................................... 12 2.1.2 Surveys ............................................................................................................................... 14 2.1.3 Metrics ................................................................................................................................. 15 2.1.4 Data Analyses ..................................................................................................................... 15 2.2 Patterns of Mesophotic Benthic Community Structure ............................................................... 15 2.2.1 Study Sites .......................................................................................................................... 15 2.2.2 Surveys ............................................................................................................................... 15 2.2.3 Data Analyses: PATN© ........................................................................................................ 16 2.2.4 Description of PATN©’s Delineations for Species Groupings.............................................. 17 2.2.5 Box-and-Whisker Analysis .................................................................................................. 17 2.2.6 Habitat Characterization based on Within-Bank Distribution of Species Richness ............ 18 2.3 Relationship between Relief and Species Richness, Including Geographic Patterns ................ 18 2.3.1 Study Sites .......................................................................................................................... 18 2.3.2 Vessel .................................................................................................................................. 18 2.3.3 Collection of Relief Data ...................................................................................................... 18 2.3.4 Collection of Ecological Data .............................................................................................. 19 2.3.5 Statistics .............................................................................................................................