McGrail Bank

Color bathymetric map of McGrail Bank
McGrail Bank lies to the east of Rankin and 28 Fathom Banks and is part of the same HAPC

Bottom Depth Range: 145-490 feet (44-149 meters)

McGrail Bank (formerly known as 18 Fathom Bank) is located approximately 46 km (30 mi) east northeast of Geyer Bank and 97 km (60 mi) east northeast of East Flower Garden Bank. It consists of a pair of ridges separated by a valley and covers an area of approximately 28 km2 (17 mi2).

McGrail Bank has the shallowest crest of any of the shelf-edge banks west of the Mississippi delta, excluding the Flower Garden Banks. The top of the bank lies 45 m (145 ft) under water and features areas of coral reefs dominated by large colonies of the blushing star coral, Stephanocoenia intersepta. This is unique in the sense that no other coral reef is known to be dominated by this species. Other reef-building corals are also present, but in smaller numbers.

Small colonies of blushing star coral surround a pink sponge and a long-spined urchin
Blushing star coral (foreground, far left, and far right) is the dominant coral species at McGrail Bank

Deeper reef habitat includes extensive coralline algae and deep coral assemblages. McGrail Bank is designated as a Habitat Area of Particular Concern (HAPC), which protects the bottom habitat from fish traps and anchoring.

McGrail Bank was named after David W. McGrail, an oceanographer with Texas A&M University and the U.S. Coast Guard.

Tropical reef fish swim among a variety of black corals and gorgnians scattered across a section of deep reef
Bank Butterflyfish and Roughtongue Bass swim through a variety of black corals and gorgonians at McGrail Bank
A stark white gorgonian bush anchored to the sea floor near a white corkscrew coral.
A large gorgonian colony in the mesophotic habitat at McGrail Bank

Video

The following video is a compilation of footage taken during ROV (remotely operated vehicle) and manned submersible explorations at McGrail Bank.

0:00 A bathymetric map of McGrail Bank followed by a second map showing the actual exploration tracks that the ROV and submersible traveled to acquire the following footage in an area about 180-200 feet deep (24-61 meters).

0:18 A small, one-person submersible sitting on the bottom at various locations, large groups of creolefish milling about in almost every part of the reef, coral and sponge areas, sponge and algae areas, grouper, snapper, blue chromis, reef butterflyfish, creole wrasse, rock beauty, large school of yellow goatfish, squirrelfish, large coral mounds, rubble and algae area, horseye jacks, submersible above the reef.

2:12 Creolfish swimming over reef and sand/rubble. Closeup views of a large, lacy-looking leafy algae, a small hermit crab feeding alongside the algae, and a variety of fish surrounding the glass dome of a submersible with a person inside.

2:40 Submersible turning above the reef then continuing with ling, Spanish hogfish and jacks swimming around it.

2:55 Discarded barrel on the reef, encrusted with organisms. Longspine squirrelfish and yellow goatfish swimming nearby. School of creolefish swimming above the reef.

3:10 Algal nodule zone transitioning to a leafy algae area with schools of slender, silvery fish swimming above.

3:24 Large school of creole wrasse and a few creolefish swimming above the reef.

3:32 Sea star on the bottom with brown chromis, spotfin hogfish, a dog snapper and creolefish swimming nearby.

3:39 Sandbar shark cruising across the reef with some jacks.

3:45 Close up view of a marbled grouper with creolefish and a pair of reef butterflyfish.

Video Length: 3:56

Credit: FGBNMS