Southern stingray.

Green moray eel

Green moray eel

Green moray eel

Green moray eel

Black durgon

Trumpetfish

Saucereye porgy (Calamus calamus)

Rock beauty

Rock beauty

Squirrel fish

Squirrel fish

Schoolmaster snapper (Lutjanus apodus)

Schoolmaster snapper (Lutjanus apodus)

Long-spine porcupine fish (Diodon holocanthus)

White grunt (Haemulon plumieri)

Bluestriped grunt (Haemulon sciurus)

French grunt (Haemulon flavolineatum)

Bluestriped grunt (Haemulon sciurus)

Stoplight parrotfish supermale (Sparisoma viride)

Stoplight parrotfish supermale (Sparisoma viride)

Stoplight parrotfish supermale (Sparisoma viride)

Black durgon (Melichthys niger)

Black durgon (Melichthys niger)

Black durgon (Melichthys niger) in center, stoplight parrotfish (Sparisoma viride)in lower right, blue tang (Acanthurus coeruleus) , and parrotfish ( Sparisoma sp.) upper right.

Gray angelfish (Pomacanthus arcuatus)

Gray angelfish (Pomacanthus arcuatus)

Queen angelfish (Holacanthus ciliaris)

Queen triggerfish (Balistes vetula)

Indigo hamlet (Hypoplectrus indigo)

Anemone

Red sponge

Yellow tube sponge

Yellow tube sponge

Sponge biodiversity and morphotypes at the lip the wall site in 60 feet of water . Included are the yellow tube sponge, Aplysina fistularis, the purple vase sponge, Niphates digitalis, the red encrusting sponge, Spiratrella coccinea, and the gray rope sponge, Callyspongia sp.

Xestospongia muta, the barrel sponge, may live for 100 years and grow to over 6 feet tall. While populations have declined at sites throughout the Caribbean, they appear to be quite healthy on Little Cayman Island.

Some sponges, like this vase sponge (Callyspongia plicifera), do not host a microbial community that is substantially different from that found in the surrounding water column. Other sponges contain microorganisms that are not commonly found in the water and they are considered bacteriosponges.

This brown sponge (Agelas conifera) is common on both shallow and deep Caribbean reefs, but grows to enormous proportions on deeper reefs where it can orm long creeping arms extending into the depths.

The liver sponge, Plakortis sp., produces a series of important chemical compounds that deter predators and have biomedical antimicrobial activity.

Agelas conifera is a common sponge of the Caribbean over a broad depth gradient. This makes it a great model organism to study phenotypic plasticity.

Purple sea fan (Gorgonia ventalina)

Several species of gorgonian octocorals occur on deep reefs. Nicella schmitti, shown here, lacks zooxanthellae, but feeds on particulates and small zooplankton that are abundant along walls.

Plating Agaricids are common down to about 200 ft on the Little Cayman walls, in shallower water they tend to form smaller plates with upright ridges. These differences in morphology may be a mechanism to efficiently gather light for their zooxanthellae.

One of the more common deep reef corals on the Little Cayman walls are Mycetophyllia sp. since they prefer low light conditions. In fact, on shallow reefs, Mycetophyllia polyps are often retracted during the day.

Team TZ members conducting a site survey at a depth of 40 feet. The team members are taking notes of what they see along the tape in 10 cm increments and 50 cm on either side of the tape. They recorded all sponges and corals they see which is correlated with position information.

A Hawksbill turtle feeding on a sponge.

Although many of the species found at depth will likely be different than those seen on shallow reefs, some mobile organisms can actually move between shallow and deep reefs. This hawksbill sea turtle feeds on sponges which are common in both deep and shallow reefs.

The precious black corals are also common on the wall faces, rarely above 150 ft depth due to prior harvesting for the jewelry trade.

As light becomes limiting in the deep reef fewer hard corals are able to survive, but many species of soft corals and black corals serve the same functional role as habitat and/or food.

The biodiversity of vertical walls can be impressive, as this photo from the Indo-Pacific region demonstrates.