A Quick Tour of Thunderball Grotto

Staniel Cay, Exumas, Bahamas  Coordinates: N25° 11.039′  W76° 24.473′   Depth 0-15 ft.  This is one of my favorite snorkels here in the Bahamas. This cave is located at Staniel Cay and was the set for a famous scene in the 1965 James Bond movie Thunderball. Tour groups come to see it by the droves swimming in for about 15 minutes to see the cave itself and completely missing the amazing life all around them.  Be aware of strong tidal currents in some places—best time to go is at low slack tide but, of course, that’s when everyone is there.  The rock islands nearby also are interesting for snorkeling but, again, watch out for the currents. Outside the cave is a beautiful coral reef that comes right up to the surface.

At high tide the entrance is covered with water–you have to dive under a ledge to get inside.  It’s a short dive under the rock.

No Fishing sign marks the Grotto site.

It was not particularly clear when we started this dive.  This is the entrance to the cave.  Note the cluster of coral and sponge on the lower left.

The cluster of coral and sponge on the bottom left looks dull from a distance in the dim light but you can see the colors come out when you get closer–next picture

If you can dive down a little closer you find the rock is covered with sponge and coral.

Center top is a Mustard Hill Coral (Porites astreoides) and right below it is probably a Brown Tube Sponge (Agelas conifera).  Another small Mustard Hill Coral is to the right of the sponge–this colony tan in color.  Branching Fire Coral and a small finger coral can be seen to the right of the large Mustard Hill Coral.

Take a look around the entrance–It is covered with sponge and coral.

Finger Coral (Porites sp.) can grow in large dome-shaped masses.  In this picture some of the polyps are extended, giving the coral a fuzzy appearance.  Finger coral often has its polyps extended during the day.  Some other corals only extend their polyps at night.  The Green Finger Sponge (Iotrochota birotulata) is found throughout the Grotto in tangled masses along with the maroon colored sponge that is intertwined with it.

As you go in the grotto, look to the left.  There is a crack in the rock where larger fish like to congregate.

Large snapper a Queen Angelfish and a Sergeant Major hanging out just inside the grotto entrance.

You may be accosted by a school of Sergeant Majors

People feed these guys and they can be quite pesty but will not hurt you.

Then, take your head out of the water—and you are inside.

Light shines in from a hole in the top of the cave.  Some people like to climb up and plunge into the grotto from the top.

The light is dim inside the cavern and colors are washed out.  If you have a camera with a flash you will be surprised by the vibrant colors of the sponges attached to the walls of the cavern.

If the sun is shining high in the sky it will illuminate the bottom rich with multicolored sponges.
The dull-appearing bottom explodes with color when you use the camera flash.

Look for this large odd-shaped sponge on the bottom.

This may also be a Brown Tube Sponge.
Here he is lit up.  Sponge identification is tricky.  A sponge species may have various shapes and colors.  Proper identification requires looking at the spicules, microscopic hard pieces the sponge makes for protection and structure.  The spicules are in characteristic shapes for each sponge species.

At the other end of the grotto is a large opening.

Swim-through to the outside.

Opening out to a beautiful coral garden.

Pillows of Yellow Pencil Coral (Madracis auretenra) and Porites sp. along with sponges and soft corals are just outside the backside of the grotto.

There is an overwhelming diversity of corals and sponges.  The more you look the more you see.

Yellow Pencil Coral is in the top left. Next to it is a small colony of Porites sp. finger coral with pink rope sponge interspersed within the coral fingers.  Under this is Mustard Hill Coral.  The fish are small parrotfish and there is a Blue Tang (Acanthurus coeruleus) near the top center.
Rope sponges form tangled masses all around the reef.
Bright green Ten-Ray Finger Coral (Madracis carmabi) on the left, a Blue Azure Sponge in the middle and Lettuce Coral (Agaricia agaricites) on the right.
Brain Corals are a bit easier to identify than some.  This one is probably Boulder Brain Coral (Colpophyllia natans).  To the left is some Porites sp. finger coral.
Branching Fire Coral (Millepora alcicornis) is distinctive with its smooth thin branches sticking out and sometimes encrusting other corals.  Also in this picture are Mustard Hill Corals, Lettuce Coral (center left), brown sponges (center), a purple sea Fan (top center and center right), and a sea whip, a branching soft coral (right).
This Pink Vase Sponge (Niphates digitalis) is not pink–it is blue and has Lettuce Coral growing in it.

The near vertical walls are covered in plate-type corals.

Lettuce Coral at the top with a cascade of plate-growth Mustard Hill Coral.  Interspersed are some greenish sponges.  You can see their rows of oscula (openings that water flows out of the sponge)
Mountainous Star Coral (Orbicella faveolata) is normally an encrusting and plating form.  There is a sponge in the middle and the fish are French Grunts (Haemulon flavolineatum).
This is probably Mountainous Star Coral in its smooth sheet scroll form. Porites sp. finger coral is in the foreground and you can see the oscula of a large yellowish sponge on the top right.
Bright green polyps are expanded on the colony pictured above.
Lettuce Corals can be identified by their wavy-line pattern.  Green Finger Sponge, Porites sp. Finger Coral and various orange and yellow sponges are here.  Look carefully and you can see the curled arms of a Beaded Crinoid (Davidaster discoideus) emerging right below the lettuce coral that is top-center.
Close up of Lettuce Coral (Agaricia agaricites) with a brilliant orange sponge and a tiny Sea Fan in the upper right corner.  Close up, the wavy lines are actually small compartments where the coral polyps live.

It is easy to see Crinoids (Feather Stars) under ledges and among the plate corals but you can even spot them in holes close to the surface.  Crinoids are Echinoderms related to sea stars, sea urchins, and sea cucumbers.

The Crinoid in the middle is attached to the rock with small arms called cirri. The longer arms radiate from the center and troll the waters for food particles.  Crinoids can detach and swim by moving their arms.  Also in this picture is a purple sponge (left) and an Arrow Crab (right).

Off in the deeper water is a forest of soft corals.

Several species of sea whips (branching soft coral) and some Green Finger Sponge.
Sea whips and Mustard Hill Coral cover a rock wall outside the grotto.

On your way back to the dinghy, near the entrance to the grotto, there is a sandy, rubble-strewn place you might be able to see a Yellow Headed Jawfish (Ophistognathus aurifrons).

Hang at the surface and look patiently at the holes in the bottom.  You might see these 3-4 inch fish emerge from their holes.

There is way too much here to include in one blog.  There may be sequels!


3 thoughts on “A Quick Tour of Thunderball Grotto”

  1. I enjoyed your blog. It sounds like you didn’t see any coral bleaching and pollution. I would be interested in reading what you find in a few years.

    1. Thanks for your comment. I have been diving this sight for 5 years now and despite its heavy use, the coral appears to be in reasonably good shape so far.

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