Charonia tritonis (Linnaeus, 1758)
Triton's trumpet shell, 470mm

Charonia tritonis is the largest shelled gastropod in the Marshalls. Among shell-less gastropods, only the Spanish Dancer nudibranch Hexabranchus sanguineus seems to exceed it in length. Large individuals are quite scarce but can be seen in various habitats throughout the atoll, from shallow reefs to lagoon slope Halimeda patches, to lagoon pinnacles and the deep lagoon bottom. They also live along the seaward reef, both on the top of and down the slope. One was spotted at Enewetak from the submersible Makali'i deeper than 150m. Younger specimens like the one immediately below can sometimes be found in seaward reef ledges and caves at night, where they feed mostly on various kinds of starfish.

The one below is eating a young cushion star, Culcita.

Here is a close view of the antennae. The left one has a small black eye near the base.

This one is showing some interest in the starfish Neoferdina cumingi.

This rather old and crusty triton was found eating a Linckia multifora starfish.

Below are three shots of tritons feeding on the crown-of-thorns starfish, Acanthaster planci. While I do not think it has ever been confirmed that predation on these coral-eating starfish by tritons helps to limit starfish populations and help protect the reef, it seems like it shouldn't hurt. Occasionally, if I find a large triton, I might carry it around until I see a crown-of-thorns, leaving the shell nearby. Maybe it will get it.

One day I ran across a crown-of-thorns that was generating some mucus and appeared agitated. At first I could not see why, but then spotted this 50mm long baby triton latched onto a starfish arm, boring into it with its proboscis. He set his sights pretty high!

While starfish are the primary diet for tritons, they will also eat some other echinoderms. Christina Sylvester found and photographed this approximately 30cm shell obviously consuming an Actinopyga mauritiana sea cucumber off Kwajalein Island.

These two were in a small depression between coralheads on the slope of a lagoon pinnacle. When first spotted, the smaller one was clinging to the shell of the larger. When we came back for a later look, the smaller one was completely under the larger. Possibly a small male and larger female mating?

We see a fair number of young empty specimens. It seems that this species is at most risk from natural predation when they are young, so small ones are usually well hidden in holes and under rocks. While one would think that large ones would be immune to most predators, we have seen a couple of large tritons broken up into pieces. It must be something mighty large and strong that is getting them. Nurse sharks and loggerhead turtles are reported to eat the large queen conch (Strombus gigas) in the Caribbean, so perhaps some of the large nurse sharks we see here can break up large tritons. Although loggerhead turtles are found in all oceans, we know of no sightings around the reefs of Kwajalein, where green and hawksbill turtles are common.

Created 5 August 2010
Updated 19 April 2018

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