Reed, J., Farrington, S., Harter, S., Moe, H., Hanisak, D., David, A.

Characterization of the mesophotic benthic habitat and fish assemblages from ROV dives on Pulley Ridge and Tortugas during 2014 R/V Walton Smith cruises

2015

Miami, FL

NOAA Cooperative Institute for Ocean Exploration, Research and Technology

HBOI Technical Report Number 157

133

Cruise Report

"Three research cruises were conducted in 2012, 2013 and 2014 to the region of Pulley Ridge and Dry Tortugas to study and survey the mesophotic reef communities and fish populations. Pulley Ridge is the deepest known photosynthetic coral reef in continental U.S. waters and is located in the Gulf of Mexico, 100 miles west of the Dry Tortugas at the far end of the Florida Keys. The University of Miamis R/V Walton Smith Cruise No. WS1213 was conducted August 14-25,2012 and Cruise No. WS1312 was conducted August 12-27, 2013. In 2014, cruise WS1412 was conducted August 14-28. This report focuses solely on the results of the 2014 cruise and emphasizing the coral cover and health results. The report provides a detailed characterization of the benthic habitat, benthic macrobiota, and fish populations for each ROV dive site surveyed in 2014 with the Mohawk ROV. In 2014 a total of 24 ROV dives surveyed 27 random blocks (17 blocks in PR and 10 in Tortugas. The 24 ROV dives covered 25.68 km (PR = 15.52 km; T = 10.16 km), at depths from 27 to 115 m (PR = 64- 87 m; T = 27- 115 m). A total of 59 hours of ROV video were recorded and 5,323 in situ digital images were taken which included quantitative transect images (4,323), general habitat images, and species documentation images. A total of 116 fish taxa and 197 benthic macrobiota were identified from both Pulley Ridge and Tortugas dives in 2014. The most diverse taxa by far were sponges (78 taxa). Coverage of biota at Pulley Ridge was dominated by various algae (51.42% cover). Coralline red algae (up to 63% cover) and the lettuce-like green algae Anadyomene menziesii (10.1%) were the most common.The diversity of the scleractinian (hard) coral fauna at these mesophotic reef sites is quite rich; a total of 27 coral species were identified at all sites. Corals only accounted for about 5% of the living benthic cover. This research and cruises were funded by the NOAA-NOS-NCCOS grant titled Connectivity of the Pulley Ridge-South Florida Coral Reef Ecosystem: Processes to Decision-Support Tools. These cruises were conducted in collaboration with the University of Miami, HBOI-CIOERT, NOAA Fisheries, and the University of North Carolina at Wilmington which operates the Mohawk ROV, owned by Flower Gardens National Marine Sanctuary.Ultimately these data from the various cruises will be used to characterize and document the habitat, benthic communities, and fish populations inside and outside the Pulley Ridge HAPC and between the North and South Tortugas Ecological Reserves. These data may then be compared to future research cruises to better understand the long-term health and status of these important mesophotic ecosystems and for management decisions on these habitats and key species.Reserves. These data may then be compared to future research cruises to better understand the long-term health and status of these important mesophotic ecosystems and for management decisions on these habitats and key species."

Pulley Ridge; Dry Tortugas; mesophotic; ROV; benthic cover; fish; algae; coral; Gulf of Mexico

Funded by a NOAA-NOS-NCCOS grant titled Connectivity of the Pulley Ridge-South Florida Coral Reef Ecosystem: Processes to Decision-Support Tools

NOAA-NOS-NCCOS