John K. Reed, Stephanie Farrington, María Cristina Díaz, Shirley A. Pomponi, Dennis Hanisak

Introduction

A 17-day research cruise was conducted August 12-29, 2019 by the Cooperative Institute for Ocean Exploration, Research, and Technology (CIOERT) at Harbor Branch Oceanographic Institute, Florida Atlantic University (HBOI-FAU) on the University of Miami ship R/V F.G. Walton Smith with the Mohawk remotely operated vehicle (ROV).

Two legs of the expedition were conducted. Leg 1 consisted of ROV dives with the primary objective to document and characterize the benthic habitats, benthic communities, and fish assemblages of the mesophotic (30-100 m) coral ecosystems and deep rariphotic (>100 m) zones within and adjacent to the Florida Keys National Marine Sanctuary (FKNMS) (Figs. 1-3, Table 1). Leg 2 consisted of technical scuba dives conducted within the FKNMS and Tortugas Ecological Reserves (TER) to collect corals for population genetics studies. This photo album is for Leg 1 ROV dives only within the mesophotic and rariphotic zones of the FGNMS and adjacent areas. Additional dives that are not included herein were made on some shallow reefs (<30 m) within the FKNMS and TER  and also in Pulley Ridge HAPC in the Gulf of Mexico. Previously, HBOI CIOERT surveyed with ROV the region between the TER South and the western border of the FKNMS (Reed et al., 2016, 2017). These dives only found mostly soft bottom habitat, along with some hard botttom, reef habitat primarily at depths less than 30 m in this region. The western region of the northern TER is shallow reef habitat (Reed et al., 2016, 2017), but the west facing fore reef slope abruptly ends in flat sand around 30-34 m and is not included in this current photo guide. This region was described in Reed et al. (2016, 2017). We also have described ROV and submersible dives within the rariphotic zone of the south slope of TER South, primarly along Miller’s Ledge south of Riley’s Hump (Reed et al., 2016, 2017). Weaver et al. (2006) first described the deep-water reef fishes and multibeam bathymetry of this region of Miller’s Ledge.

This publication is the first taxonomic identification photo guide of the benthic macrobiota for the mesophotic coral reefs of the FKNMS. This is a first step towards the characterization of a highly diverse and poorly known component of these unique deep-water benthic communities. From 2011 to 2019, NOAA Fisheries and HBOI-FAU CIOERT surveyed with ROV the shelf-edge and deep-water Marine Protected Areas (MPAs) and Habitat Areas of Particular Concern (HAPCs) of the southeastern US extending from South Florida to North Carolina, which covered 529 km² of sea floor at depths of 48 to 1240 m along the continental shelf. ROV photographic and video transects recorded 43,542 images. From these images, 278 photographs were selected which represented common sponge morphotypes distinguished while interpreting the ROV photo transects. This resulted in a photographic field guide of the sponges associated with these shelf-edge MPAs and HAPCs (Diaz et al., 2021). Many of these are within the mesophotic and rariphotic depth zones. We also have three photographic field guides for the mesophotic reefs of Cuba, including a sponge guide (Diaz et al., 2019), a macroalgal guide (Martínez-Daranas et al., 2018), and fish guide (David et al., 2018). Some of these species will overlap with what we have found on the FKNMS mesophotic reefs.

The data from this cruise establish current baseline information to be referenced and compared to future research cruises to identify the long-term health and status of these important ecosystems. These data are made available to the SAFMC, NOAA Fisheries, NOAA Deepsea Coral Research and Technology Program (DSCRTP), NOAA Coral Reef Conservation Program (CRCP), NOAA Mesophotic Reef Ecosystem Program, and NOAA Marine Sanctuaries to assist management on these habitats and key species.

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Reed JK, Farrington S, Díaz MC, Pomponi SA, Hanisak D. 2021. Photo identification guide of the benthic taxa inhabiting the mesophotic reefs of the Florida Keys National Marine Sanctuary. Harbor Branch Oceanographic Technical Report Number 197.