NEW ORLEANS — The only national marine sanctuary in the Gulf of Mexico has nearly tripled in size.
The addition of 14 reefs and banks to the three already included enlarges the Flower Garden Banks National Marine Sanctuary from 56 to 160 square miles (145 to 415 square kilometers), the National Oceanic and Atmospheric Administration said.
There are 13 other national marine sanctuaries, with two more in the works.
The largest addition to Flower Garden Banks, called Horseshoe Bank because of its shape, is 121 miles (105 kilometers) south of the Texas-Louisiana state line, between the sanctuary’s two original banks. At 28.7 square miles (74.3 square kilometers), Horseshoe Bank is second-largest of the 17 protected areas in the Gulf.
Horseshoe Bank is made up of thousands of “patch reefs” where corals, sponges, algae, invertebrates and fish are found, according to NOAA. The area also includes a few mud volcanoes, NOAA said on the sanctuary website.
The East and West Flower Garden Banks made up the entire sanctuary when it was created in 1992. NOAA found Horseshoe Bank when it mapped the area in 2004.
West Flower Garden Bank, the sanctuary’s largest, covers 37.2 square miles (96.4 square kilometers). Horseshoe Bank is slightly larger than East Flower Garden Bank. The smallest on the list is Stetson Bank, a 1.4-square-mile (3.6-square-kilometer) area off Texas that was added to the sanctuary in 1996.
All of the other additions are dotted off Louisiana’s coast, with the two easternmost, Parker and Alderdice banks, south of Iberia Parish. The additions range from 2 square miles (5.2 square kilometers) to 11.5 square miles (29.8 square kilometers).
Alderdice Bank includes “three spectacular basalt spires” about 60 feet (18.3 meters) tall, according to NOAA. They are about 77 million years old, making them the oldest known exposed rocks on the continental shelf along Texas and Louisiana, the website says.
Parker Bank includes significant habitat in the “twilight” area between waters considered deep and shallow. Black corals, octocorals, fish, sponges, algae and invertebrates are found on it.
NOAA released its final plan for enlarging the sanctuary in January. It became official Monday.
