Rockmover wrasse – Maui’s newest vertebratarian

MikeSevernsDiving Marine Life 1 Comment

According to the known literature, rockmover wrasses (Novaculichthys taeniourus) feed on invertebrates. They can often be seen picking up rocks and tossing them out of the way to uncover small crabs, brittle stars, snails, urchins, worms, etc. Sometimes they will even hit these prey items against rocks in an attempt to break them into more manageable-sized pieces for swallowing.

So, last week at Molokini when Kecia Joy and I saw a rockmover wrasse with what looked like a worm dangling from its mouth, it was not too surprising. Until we got closer and saw that it was not a worm, but an eel! And a species of eel that I’ve never ever seen before.

A rockmover wrasse with a snake moray in its mouth

As divers we typically see eels that are in the family of eels called morays which have long dorsal and anal fins. The eel in the rockmover’s mouth had almost no dorsal and anal fins, making it look more like a snake or a worm. This family of eels are called snake morays. I’ve probably seen only 3 species of snake morays in all my dives because they are so reclusive and almost never leave their crevices during the day. The most common snake moray that a Maui diver might see would be a tiger snake moray (Scuticaria tigrina). This one looked like it might be the brownspotted snake moray (Uropterygius fuscoguttatus), a species that reaches only 12 inches.

As the rockmover does with its invertebrate prey, it slammed the snake moray against the bottom every minute or so to somehow aid in swallowing it. Unlike invertebrates which usually break apart, the snakemoray did not break into pieces. Perhaps the rockmover was trying to break its spine or trying to kill it so that it was more flexible and more easily swallowed.

Comments 1

  1. As a videographer at Molokini for 4 years, I always enjoyed shooting this guys for great action shots. I’ve seen them do amazing things but never this, thanks for sharing.

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