Mass 'die-off' reported at Flower Garden Banks National Marine Sanctuary Divers report dead coral, sponges, sea urchins and clams

The Flower Garden Banks National Marine Sanctuary is Texas' most scenic place to dive, but it's not for beginners. The Flower Garden Banks National Marine Sanctuary is Texas' most scenic place to dive, but it's not for beginners. Photo: George P. Schmahl, Flower Garden Banks Photo: George P. Schmahl, Flower Garden Banks Image 1 of / 1 Caption Close Mass 'die-off' reported at Flower Garden Banks National Marine Sanctuary 1 / 1 Back to Gallery

GALVESTON – A mass die-off of coral and other sea animals was discovered this week on a reef in the Flower Garden Banks National Marine Sanctuary, federal officials said Friday.

Sports divers discovered the damage Monday on the East Flower Garden Bank, about 100 miles southeast of Galveston, the National Oceanic and Atmospheric Administration said in a report.

Divers from the motor vessel Fling "were stunned to find green, hazy water, huge patches of ugly white mats coating corals and sponges, and dead animals littering the bottom of the East Flower Garden Bank, a reef normally filled with color and marine life," wrote Steve Gittings, chief scientist in NOAA's Office of National Marine Sanctuaries.

Agency scientists were not immediately available for comment Friday evening.

NOAA is recommending that the public avoid diving, fishing or boating in the sanctuary until more is known about the problem. The agency wants to prevent visitors from inadvertently carrying the problem to an unaffected area and to protect divers from possibly ingesting harmful toxins or bacteria.

"At present, we are not aware of any specific risks to humans, but we are recommending this action as a precaution until more is known about the cause," said Sancruary Superintendent G.P. Schmahl.

The Flower Garden Banks reefs are considered one of the healthiest in the region at a time when a quarter of coral reefs worldwide are considered damaged beyond repair and two-thirds are under serious threat, according to the World Wildlife Federation.

The divers alerted researchers, who found "unprecedented numbers of dying corals, sponges, sea urchins, brittle stars, clams and other invertebrates on large but separate patches of the reef," the report said.

About 50 percent of corals were dead in some of the affected areas, the report said, but scientists were still trying to determine the size of the affected area. The damage has been seen at three dive sites so far.

Oddly, there was no sign of damage at a site used since the late 1980s by scientists to monitor the health of the reef, the report said. "Twelve miles away, the reefs of the West Flower Garden Bank remain vibrant, bathed in clear blue water and free of the problems for now," Gittings wrote.

Scientists are investigating possible causes, including poor water quality, disease and chemical spills, he report said. Each alone could kill organisms, but it's more likely a combination, the report said.

"We know of no spills that have recently occurred near the Flower Garden Banks," said Schmahl, "But water temperature over the banks is quite high, at 86 degrees."

Scientists are also concerned about large plumes of low-salinity coastal water that have moved offshore following months of heavy rainfall in the region and that could be sucking oxygen from the water. The coastal water is rich with plankton, nutrients and chemicals from the runoff, the report said. As the plankton decays, oxygen levels in the water can drop.

"Overall, however, the health and stability of the sanctuary's invertebrate and fish populations have been in stark contrast to coral reefs around the world that have degraded over the last four decades," the report said.

The die-off has caused concern that the isolation of the banks may no longer shield it from "human impacts," the report said. The problem now is to determine what is causing the die-off. "The sanctuary and the science community are desperately trying to figure that out," the report said.