A short video about the recent cruise. Download (47 MB, Quicktime movie)
NOAA scientists recently returned from a three-week mission to study unexplored areas of the sea floor using sonar technology off the southern coasts of St. John and St. Thomas, U.S. Virgin Islands, and eastern Puerto Rico. Along the way, the team gathered data on the coral reef habitats, fish communities and uncovered a few remnants of the region's rich maritime past.
Researchers from the National Centers for Coastal Ocean Science used robotic subs and seafloor imagers to examine coral reefs and explore areas where fish spawn in order to create detailed maps of the sea floor. NOAA is surveying the area at the request of territorial agencies and local scientists, who have determined it to be of special ecological significance.
"Little was known about the distribution, extent, and health of mid-water coral reef ecosystems and marine fish associated with them before we began studying these areas eight years ago. We are filling these data gaps," Tim Battista, lead scientist and oceanographer with the Center for Coastal Monitoring and Assessment's Biogeography Branch, said.
Scientists logged nearly 400 hours at sea, mapping over 145 square kilometers (56 square miles) of sea floor. Sonar and remotely operated vehicle (ROV) data located derelict fishing traps and spotted more than 30 invasive lionfish. Increasingly rare colonies of staghorn coral (Acropora cervicornis) were also observed. Staghorn coral was once one of the most abundant coral species in the Caribbean, but is now listed as threatened under the Endangered Species Act.
Not only did the sonar data spot plenty of interesting seafloor habitats and fish, they also located six uncharted shipwrecks. The ROV was deployed to further explore the wrecks. "What we saw was truly exciting! Finding one shipwreck would have been great, but locating six was a total surprise," Battista said. "The wrecks seemed to serve as a refuge for fish and other marine life. In several instances we saw schools of fish, sharks and turtles."
The shipwreck sightings were reported to local maritime history authorities. Experts are currently reviewing the ROV footage to learn more about the wrecks. The shipwreck data will also be used to update the region's nautical charts to improve ship navigation safety.
During a mid-cruise port visit to St. Thomas, scientists presented their most recent findings to a group of regional politicians including Congresswoman Donna Christensen and staff, as well as members of the local Senate. Other education and outreach events were aimed at engaging fishermen from the St. Thomas Fishermen's Association, local graduate researchers and grade school students.
"We gathered a lot of valuable information this year. In the coming months, we'll process the SONAR data to create seamless images of the seafloor," Battista said. "These maps will apprise managers of where key resources are located, and will help them evaluate how best to protect them and meet the community's needs."
This mission was supported by the Coral Reef Conservation Program.