Postcard from the Reef – Guard Crab

Most divers do nothing during their safety stop, I have some trouble doing that. Hanging in the water fifteen feet below the surface for five minutes is sometimes pleasant, sometimes boring.

Also hanging fifteen feet down is the mooring ball, a buoy holding a steel cable near the surface so the dive boats can avoid dropping anchor on the reef. I have made a habit of checking out the growth on the mooring ball and line during my safety stop. I have found hydroids, wire coral gobies, even corals growing here, no real estate goes unclaimed around the reef.

A set of cauliflower corals were growing on this cable, complete with the usual community of critters that find shelter in the branches. Even more convenient, I could rotate the coral colony simply by twisting the cable to which it was attached, giving me a chance for a better photo of a guard crab…

Common Guard Crab
Common guard crab (Trapezia intermedia) in a small cauliflower coral (Pocillopora meandrina) growing on a mooring buoy cable.

Postcard from the Reef – Dragon Moray

One of the rarer, but very impressive, moray eels of the Hawaiian Islands is the Dragon Moray. This is my first decent sighting of one. Decent meaning I did not see the last bit disappearing into the coral, and actually saw the head for more than a glimpse.

He was staying well out of harm’s way with noisy divers about, deep in an antler coral head. The location also made the eel fairly difficult to photograph. I used my usual in-coral-head technique… zoom in, pray for focus, and nuke the coral head with light.

Dragon Moray
A Dragon Moray (Enchelycore pardalis) in a coral head at 40ft depth, Suck ‘Em Up Cavern, Kona

Hawai‘i’s Sea Creatures

While the fish are often spectacular on the reef, it is the invertebrates that are often the most fascinating creatures to be found. Life in the sea allows for a bewildering array of body shapes and lifestyles. The creatures found by divers will often be things that stretch the imagination. The unexpected is common and the observant diver will find life forms both beautiful and horrifying.

Hoover's Hawai‘i's Sea Creatures
The cover of Hoover’s Hawai‘i’s Sea Creatures
The guide to invertebrates on the reef is Hawai‘i’s Sea Creatures, by John Hoover. Written for the non-professional there are over 500 species presented, all with excellent photographs. Each species is resented with a short paragraph or two summarizing what is known about the creature. To supplement the books, the author maintains a website with updates that can be checked when the book fails.

For someone like myself who spends much of a dive looking for the small creatures that most divers overlook this book is incredibly useful. I received the latest edition under the Christmas tree and it is often the first book I reach for after returning from a dive.

I have come across a few species not in the book. But the book will at least get you close, there will be something similar allowing you to identify the family or maybe the genus that your unknown critter belongs in. For anyone diving in Hawai‘i, this is one book that is indispensable.