Coral in Florida Keys Nursery Being Moved to Cooler Waters

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KEY LARGO, Florida Keys -- Divers with Reef Renewal, a Florida Keys-based coral restoration group, have begun moving small coral colonies from a successful shallow coral nursery located in the Florida Keys National Marine Sanctuary to deeper, cooler water.

The relocation of most of the young corals from the nursery is a proactive measure, designed to safeguard them in case water temperatures around the island chain continue to be higher than normal. 

Batches of elkhorn coral growing in the acre underwater nursery, situated in 30 feet of water off Key Largo, are being relocated to a site in cooler water at a depth of 65 feet. Other species being moved include staghorn, boulder and brain coral, which are all connected to underwater vertical rope nurseries.

The move is being conducted with the support of Florida Keys National Marine Sanctuary scientists, the Army Corps of Engineers as well as volunteer divers. Officials expect the project to be completed by the end of next week.

“By relocating these corals to deeper, cooler waters, we hope they’ll have an increased chance of making it through the coming weeks,” said Dr. Katey Lesneski, the sanctuary’s Mission: Iconic Reefs research and monitoring coordinator. 

Due to warmer-than-usual ocean temperatures, some coral in the Middle and Lower Keys began bleaching in late July, a stress response to high temperatures or disease. Marine scientists including Reef Renewal’s Ken Nedimyer, an internationally acclaimed coral restoration pioneer, say that bleaching doesn’t mean all coral in the Florida Keys is dead.

“You hear a lot of stories that the reefs are 100 percent dead or that they’re all bleached and dying, and that’s not the case,” Nedimyer said. “We’ve been diving a lot in the Upper Keys and some of the offshore reefs are fine.

“Not all corals are bleached and not all corals are going to die,” he added.

Corals in other ocean nurseries in the Keys have been moved to land-based nurseries over the past week. The Reef Renewal relocation is the first-time ocean-based nursery coral is being moved to a new and deeper underwater location. 

Some baby corals, however, will remain in the shallower nursery to provide an opportunity to compare temperature impacts.

Sanctuary scientists were surprised to discover how healthy all the coral in the Reef Renewal nursery was. According to their observations, none of it had been bleached or otherwise impacted by warmer water temperatures. 

Since marine sanctuary officials expect warm water conditions to last through September, the healthy corals were moved as a preventative measure. 

Nedimyer said he and other scientists are being asked if the current marine heat wave is the “new normal” in terms of climate change. 

“I don’t think this is the norm, but this could be a glimpse of what the future is going to look like, so we need to start preparing for it,” Nedimyer said. “This is a good wakeup call.” 

The raising of reef-building species of coral is an important aspect of the marine sanctuary’s Mission: Iconic Reefs initiative, which aims to strengthen and restore seven of the Florida Keys’ iconic reef tracts. 

Corals are a significant contributor to the water-based economy and way of life for millions of Florida and Caribbean residents. They also are an important buffer to coastal areas, decreasing wave heights and flooding during tropical cyclones.

“Coral reefs are incredibly important not only because of the ecological benefits and services they provide, but that is well intertwined with all the economic benefits,” said Lesneski.