Conchs & Co.

The huge Queen Conchs of the Caribbean are highly regarded as food, which has had a drastic impact in many areas. In SE Asia the species are smaller and very well camoflaged. They are also edible but there appears to be no commercial fishery.

Conchs graze on algae and detritus films on plants and stones. This makes them of prime importantance in shallow water ecosystems.

One characteristic feature is a notch in the outer lip that enables the conch to stick out its' right eye above its' upper surface without exposing the rest of the body. Males and females are separate. 100 000 to 500 000 eggs are laid in a gelatinous tube and generally held under the lip of the shell until hatching.

The heavy-shelled helmets and thinner shelled Cassids are active hunters of sea urchins, sand dollars, and sand dollars. I have personally seen a Phallium in hot persuit of a heart urchin (Lovinia), finally overwhelming and consuming it.

The majority of Eulimid snails are parasites on starfish and sea urchins. Thyca crystallina is most commonly seen in SE Asia. They feed on the body fluids of their host, and some become embedded in the host body as the starfish grows. Echineulima asthenosomae seems to feed on the spines of Fire Urchins, but appears to do no harm.

Moon shells are quite fast moving predators on molluscs, particularly bivalves. When they find a mollusc, they drill a hole through the shell with their radula, softening the shell with acid as they go. Their probosis is then inserted through the hole and their prey eaten from the inside!

The round sand-impregnated "collars" that are often seen on sand and reefs are the egg cases of moon shells. Some species produce sausage-like egg masses.

The Triton Trumpet is a large predatory shell (the second largest in the world) best known as the main predator of the Crown of Thorns (COT) starfish, though it does eat e.g. Linkia as well. Over-collecting by shell hunters in some areas greatly reduce numbers and the COT populations rise.

Tun shells are large and thin with a very large body. They are active at night is sandy/silty areas, actively hunting sea cucumbers, which they seem to swallow whole.

A thick mantle covers the very thin, flattened shell of these snails which causes many people to mistake them for sea slugs. They have a pair of head tentacles, as can be seen in the photo of the juvenile.

Colonial ascidians seem to be their main food.

These snails have an irregularly shaped tubular tubelike shell either cemented to the substrate or embedded in a sponge. They secrete a sheet of mucus into the current which traps food items that pass by. Every few minutes they withdraw the mucous sheet to harvest the catch. A new mucous sheet is then secreted.