Stetson Bank

Bathymetric map of East Flower Garden Bank showing the sanctuary boundary, as well as other relevant management zones and infrastructure.
Stetson Bank is a mid-shelf bank located 80 miles off the Texas coastline. Credit: FGBNMS

Depth Range: 56-200 feet (17-61 meters)

Distance from Land: 80 miles (129 km)

Area: 1.4 square miles (3.6 sq km)

Stetson Bank, located at the westernmost end of the sanctuary, is an oblong, mid-shelf bank made of uplifted siltstone and claystone. It was added to the sanctuary when Congress reauthorized the National Marine Sanctuaries Act in 1996.

The original boundary was a rectangle around the bank. This excluded some portions of what we now call the Stetson Ring, a group of deep habitat features that surround the bank, because it was unknown at the time.

Coral Community

The reef crest of Stetson Bank is considered a coral community, rather than a true coral reef. Since it is further north than the Flower Garden Banks, it is cooler in winter and therefore doesn't support much reef-building coral. Instead, it is dominated by algae, sponges, and fire coral.

Rocky outcrop covered in algae, sponge, and fire coral, with a diver floating in the background
Rocky outcrops at Stetson Bank are covered mostly in algae, sponges, and fire coral. Photo: G.P. Schmahl/FGBNMS

Rocky outcroppings rise alongside gravelly sand flats populated with clusters of tube sponges. A fair amount of algae grows in the flats at certain times of year, while at other times it can seem quite barren.

Small fish gather around two clusters of tube sponges in an open area of reef
Tubes sponges attract small fish and invertebrates in the open sand flats at Stetson Bank. Photo: Emma Hickerson/FGBNMS

Sponges of every conceivable color and shape cover large sections of the reef.

Black, purple, orange, and red sponges surrounded by leafy algae on a reef.
The diversity of sponges at Stetson Bank is amazing. Photo: Emma Hickerson/FGBNMS

Erosion of the softer layers of the upthrusted rock formations has resulted in distinct, parallel ridges at many locations.

Coral reef with purple fish swimming above it
Rocky ridges provide habitat for urchins, sponges, and fish. Photo: Emma Hickerson/FGBNMS

The highest peak of Stetson Bank is known as Sierra Madracis because of the predominance of Madracis decactis (ten-ray star coral) growing there. It is a hub of activity for thousands of fish and home to many large spiny lobsters. No other section of the bank has such a high concentration of coral.

Coral covered peak surrounded by lots of reef fish
Sierra Madracis is almost always swarming with fish, not to mention a few lobsters tucked back in its crevices.. Photo: Emma Hickerson/FGBNMS

Stetson Ring

A circle of low profile features in the deep area surrounding the bank was first mapped in 1997 and identified as an important part of the salt dome formation. Additional mapping conducted by FGBNMS over many years completed the Stetson Ring dataset, and in 2021 the boundary was expanded to include the entire ring.

Uplifted siltstone and claystone boulders are the main features of the ring, which provide mesophotic habitat for black corals, octocorals, sponges, invertebrates, and many of the same fish species seen on the reef crest.

An arrow crab rests just below an outcrop containing a hard coral and a Christmas tree worm
A Stetson Ring outcropping covered in corals and algae provides habitat for an arrow crab and a Christmas tree worm. Photo: FGBNMS/UNCW-UVP
A magenta colored sea fan in deep habitat
Sea fans found around the Stetson Ring can be quite colorful. Photo: FGBNMS/UNCW-UVP
Two black and white striped fish swim next to bright red and purple sponges in deep habitat with small purple fish swimming between their branches
Some of the same fish species seen on Stetson's reef crest, like these high hats and purple reef fish, are also found in the deep areas of the Stetson Ring. Photo: FGBNMS/UNCW-UVP

Who Was Henry Stetson?

Henry C. Stetson (1900-1955), a Woods Hole Oceanographic Institute geological oceanographer, designed early seafloor coring and dredging equipment for exploration. He was the first person to identify the existence of corals on the Flower Garden Banks in 1953.