Wednesday, May 9, 2012

Mystery Crab

I saw this tiny crab on a recent twilight dive at Honaunau and have been unable to identify it. It seems like the distinctive heart-shaped white area on the carapace would make ID simple, but I haven't seen anything like it in my reference books or on the web. Any help in making the identification would be greatly appreciated!


Photos Copyright 2012 by Barry Fackler


Friday, May 4, 2012

Night Dive 4/20/12

I haven't been on a night dive in several years, mostly because the logistics of donning/doffing gear as well as ingress/egress from the ocean in darkness just seemed like too much of a hassle. But, after a while, one likes to see new things and wonders if the old bones are still up to the challenge. On April 20th, I packed my gear after work and drove to the ol' swimming hole at Honaunau to explore the nocturnal reef.

Photo Copyright 2012 by Barry Fackler

The first thing one notices upon descent is all the tiny little lights glowing on the coral everywhere you aim your torch. These lights are reflections off the eyes of countless shrimp that come out of the coral at night to feed and do whatever else shrimp do when they're not hiding. The most common shrimp I saw was the Marbled Shrimp (Saron marmoratus) the males of which have absurdly long claw-arms.

Photo Copyright 2012 by Barry Fackler

While yellow seems to be the predominant reef color of the day, red most definitely rules the night. Many scarlet crustaceans come out as do crimson fish. I found this little red crab perched on a single lobe of coral. I cannot positively identify it as it is probably a juvenile and may have different morphological characteristics than the adult.

Photo Copyright 2012 by Barry Fackler
This Blackside Hawkfish (Paracirrhites forsteri) is usually brownish with black sides during the day but becomes reddish-pink at night. This one was quite asleep and allowed me to take several close-range photos without flinching. The small, blurry objects are zooplankton attracted by the dive torch.

Photo Copyright 2012 by Barry Fackler


I mostly stayed in the area of a large sand patch that was simple to navigate as it is easy to lose your bearings in the darkness. While I mostly looked for photo ops in the surrounding coral, I couldn't pass up this bright Red Swimming Crab (Charybdis paucidentata) posing out in the open on the sand.

Photo Copyright 2012 by Barry Fackler

This Manybar Goatfish (Parupeneus multifasciatus) is another diurnal fish that sleeps soundly under overhanging coral at night. It is a close relative of the Minibar Goatfish that can be frequently found in hotel rooms.

Photo Copyright 2012 by Barry Fackler
There would not be much of a meal in a Red Reef Lobster (Enoplometopus occidentalis). While being a lovely crustacean, it is about the size of a freshwater crawfish or crawdad with a length of about five inches being the max.

Photo Copyright 2012 by Barry Fackler
I saw several endemic Hawaiian Whitespotted Tobies (Canthigaster jactador) sleeping in this vertical orientation. This fish does not seem to change color at night.

Photo Copyright 2012 by Barry Fackler
By the time I happened upon this Lowfin Scorpionfish (Scorpaenodes parvipinnis) the zooplankton was getting thick! This fish is not sleeping as it is nocturnal. I have seen them sleeping in caves during daytime hours.

Photo Copyright 2012 by Barry Fackler

Even challenging dives are tough to end. You'd like to keep poking around and searching the reef for hours. As I made my way back to shore, I snapped this photo of a Rough-Spined Urchin (Chondrocidaris gigantea). These echinoderms are able to contort their many spines to allow them to wedge into the reef during the day. They come out to roam at night when predators are fewer.


Photo Copyright 2012
This is the photo I came out to get! This Bullethead Parrotfish (Chlorurus spilurus) is sleeping in a nearly invisible mucus cocoon which prevents predators from catching its scent. During the day they swim swiftly and erratically from one coral head to the other scraping off coral with their "beaks" (actually, fused teeth) to feed on the algae within. Their dramatic colors become even more lurid after dark.

Thank you all for joining me on this little adventure. I did another night dive on April 27th and will be posting on that "relatively soon".