Hurricane Irma Spared Florida Bay

Hurricane Irma largely spared Florida Bay, according to Audubon Everglades Science Center staff in Islamorada, Florida Keys. After the category four storm surged through the Florida Keys Sept. 10, South Florida residents, fishing captains and scientists were nervous about how the well-loved and productive bay had fared. Algal blooms and dead seagrass concerned scientists for the past two years, and massive and expensive Everglades restoration projects were demanded to save the unique bay. But, Mother Nature appears to have intervened in a nurturing way. Birds, fish, foliage and water quality all were thought to have survived and partially benefitted from Irma’s path through Florida’s southern islands. Research Manager of the Everglades region, Peter Frezza, said Irma’s effects were nothing like the harm done by Hurricane Wilma on Oct. 24, 2005.

A reconnaissance voyage Sept. 19 led Frezza to observe, “There was far less visible damage or signs of disturbance than I expected.” Initial observations from the air had sounded dire. An aerial tour of Everglades National Park and Florida Bay a couple days after the hurricane led aquatic ecologist Stephen Davis of The Everglades Foundation to sound the alarm over massive amounts of floating seagrass. Seagrass serves as important nesting grounds for juvenile marine life, important feeding areas for birds and a component of stabilizing the sea’s bottom and improving water quality as it traps sediment. Dead grass could create an algae bloom.

In 2015, a drought killed about 60 square miles of seagrass and turned the water a sickly yellow color that triggered a massive algae bloom.

“There is a lot of [floating] seagrass,” Frezza continued, “but 95 percent of it is manatee grass not turtle grass which is the primary grass in Florida Bay.” Manatee grass is cylindrical and can grow to 18 inches long. Turtle grass is much shorter and has flat narrow leaves. Turtle grass has deeper root structures than any of Florida’s other seven seagrasses, according to the Florida Department of Environmental Protection.

“Rankin Basin, [about midway between Florida’s coasts], was basically Ground Zero of the seagrass die-off, and the water and grass looked very healthy there.”

Frezza observed that the floating seagrass is dispersing, and seagrass pushed up on beaches provides nutrients for seabirds.

At Trout Cove near Joe Bay in the eastern Everglades, a popular fishing area, there was a small algal bloom.

Ten days after the storm, Florida Bay was still murky due to Irma’s winds. Despite a week of calm water and winds, sediment had stirred and was still settling, said Frezza. There was no large-scale harm to mangroves or trees; and channel markers, for the most part, were intact.

Five sponges, normally anchored to the bay bottom, were floating — not a major loss, considering what could have been. Sponges serve as a filter by pumping large quantities of water through their bodies in order to extract tiny organisms for food from the water.

While the highest storm surge was at Cape Sable, the western area of the Everglades, there was no new breaching of canals, Frezza said. The western storm surge was seven feet high, compared to about three feet in the east.

The tie-off dock used by fishermen and canoeists to access East Cape is no more.

Frezza also said Carl Ross Key near Sandy Key got “beat down; it’s going away.” It is a tent camping spot; however, erosion and natural processes seem to have marked it for elimination.

On the other hand, new little islands are forming and are teeming with baitfish – pilchards, pinfish, silver sides, mullet, needlefish and little snapper.

After a couple visits to Florida Bay with fellow Audubon staff, Frezza observed, “I’m optimistic about the future.”