Scientific Clues Connect the Deep Reefs of Pulley Ridge to Florida Keys

This week, a team of university, state, and federal scientists is exploring a little known deep reef, Pulley Ridge, where spectacular plate coral colonies blanket the seafloor and red groupers actually help create habitat.

Scientists believe this ecosystem, which lies 33 miles northwest of the western most boundary of the Florida Keys National Marine Sanctuary, serves as a source of invertebrate and fish larvae riding the Loop Current’s easterly and southward curvature from Florida’s coast to the sanctuary.

The deepest known photosynthetic coral reef off the continental U.S., Pulley Ridge is home to giant barrel sponges and largely undisturbed plate corals (Agaricia sp). Nearby, pits in the seafloor created by red groupers make for a complex habitat that supports a wide range of other species – including colorful fish such as the purple reef fish and tasty ones such as vermillion snapper.

Onboard the University of Miami Rosenstiel School of Marine and Atmospheric Science’s R/V F.G. Walton Smith, the team will be conducting its final field work excursion from August 22 – September 4. Using the Remotely Operated Vehicle (ROV) Mohawk, owned by the National Marine Sanctuary Foundation and the Flower Garden Banks National Marine Sanctuary and operated by the Undersea Vehicles Program at the University of North Carolina Wilmington, the team will collect seafloor images and take samples of marine life. The images will help scientists characterize the benthic (seafloor) and fish communities and the samples of marine life will aid in identification of specific species.

One of the highlights of the multi-year research project was last year’s discovery of a large patch, greater than 65 yards across, of nearly continuous plate coral (Agaricia spp). An overview of the latest science on the Pulley Ridge ecosystem was reported to the sanctuary’s advisory council last week at their bimonthly meeting by Dr. Shirley Pomponi, a sponge biologist who works for Florida Atlantic University Harbor Branch. Her team has received NOAA funding from the Cooperative Institute for Ocean Exploration to study Pulley Ridge.

“We will be looking at the science from this project to see how closely fish, corals, and marine life in Pulley Ridge are connected to the Florida Keys,” said Sanctuary Superintendent Sean Morton.

Pulley Ridge is one of the areas that the Sanctuary Advisory Council requested NOAA analyze for potential inclusion within the sanctuary. The Gulf of Mexico Fishery Management Council has already designated it as a Habitat Area of Particular Concern (HAPC) in 2005, because it fits the criteria of being rare, ecologically important, and susceptible to environmental stress (e.g., oil spills). Specific fishing regulations in place within the HAPC prohibit bottom anchoring by fishing vessels, bottom trawling, longlines, buoy gear, and all traps and pots. However, the HAPC designation does not protect Pulley Ridge from anchoring by non-fishing vessels, impacts from divers, or from any other non-extractive uses, all of which can impact the health of the reef. Also, some of the more newly discovered reefs at Pulley Ridge are not protected as part of the HAPC.

If it were to become part of the sanctuary, additional management capabilities available under the National Marine Sanctuaries Act would provide further protection to Pulley Ridge from non-fishing related activities such as anchoring, discharges and dumping, cable laying, or oil, gas, and mineral extraction.

“Understanding the connectivity of Pulley Ridge to the greater Florida Keys ecosystem will be critical for determining whether the boundaries of the Florida Keys National Marine Sanctuary should be expanded to include Pulley Ridge,” said Morton.

Learn more and follow the cruise at NOAA’s Ocean Explorer website.

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