The Right Blue

Nudibranchs in The Right Blue

Nudibranchs-- also called sea slugs -- are marine gastropod molluscs (snails) that do not have a shell. (The name 'nudibranch' means bare gills.) Most tropical nudibranchs are small and brightly colored, so they are a popular subject for underwater macro photography.

Here is a directory of articles about nudibranchs in The Right Blue:

Trailing behavior in Risbecia nudibranchs (Risbecia pulchella)- Sep. 1, 2008
Exotic Underwater Nudies - The Spanish Dancer (Hexabranchus sanguineas)- Sep. 18, 2008
Hawaii's Gold Lace Nudibranch (Halgerda terramtuentis) - Sep. 29, 2008
The Blue Dragon, a Solar-Powered Nudibranch (Pteraeolidia ianthina) - Oct. 12, 2008
Dotted Sea Slug from the Mediterranean (Peltodoris atromaculata) - Oct. 25, 2008
The Blue Sphinx nudibranch (Phyllidiopsis sphingis) - Mar. 9, 2009
How do critters get their scientific names, and what do they mean? - June 13, 2009
All set for a pajama party on the reef? (Chromodoris quadricolor) - June 13, 2009
Purple sea slug (Hypselodoris apolegma) - Apr. 15, 2010

Here is a directory of nudibranch photos on The Right Blue, sorted alphabetically by family name and species name:

Asteronotidae

Gold Lace nudibranch (Halgerda terramtuentis), Hawaiian endemic species, two macro photos - Pacific: Puako, Hawaii

Chromodorididae

Coi nudibranch (Chromodoris coi), macro photo - Celebes Sea: Pulau Sipadan
Striped Pajama nudibranch (Chromodoris quadricolor), macro photo - Red Sea: Egypt
Striped Pajama nudibranch (Chromodoris quadricolor), feeding on sponge - Red Sea: Egypt
Vibrating nudibranch (Chromodoris vibrata) - Pacific: Puako, Hawaii
Purple sea slug (Hypselodoris apolegma), macro photo - Celebes Sea: North Sulawesi
Pair of Risbecia nudibranchss (Risbecia pulchella) - Red Sea: Ras Mohammed, Egypt

Discodorididae

Dotted Sea Slug (Peltodoris atromaculata), three macro photos, incl. feeding behavior - Aegean Sea: Greece

Hexabranchidae

Spanish Dancer (Hexabranchus sanguineus), largest nudibranch species in the world - Red Sea: Gordon Reef
Spanish Dancer egg mass rosettes (Hexabranchus sanguineus), bottom of page - Celebes Sea: Bunaken Island, Indonesia

Phyllidiidae

Blue Sphinx nudibranch (Phyllidiopsis sphingis) - Pacific: Puako, Hawaii

Pteraeolidiidae

Blue Dragon nudibranch (Pteraeolidia ianthina), two macro photos - Celebes Sea: Malaysia and Indonesia

Nudibranch video:

Spanish Dancer (Hexabranchus sanguineus), shows how the creature 'swims'

Knock-knock: Who's there? A surprise from the past

by B. N. Sullivan

When I used to shoot film underwater, I made it a habit to mark a code number on the frame of each of the slides as soon as they had been developed. The coding system I devised long ago consists of a number that corresponds to a particular entry in my dive logs -- that identifies the when and the where -- plus a letter code that indicates something about the subject.

Jerry finished scanning all of our old underwater photography slides awhile back, and as he went along, he labeled each with its original ID number and sorted the scanned images into folders according to the subject code on the slide. I still have not finished reviewing all of the thousands of images, but every once in awhile I sit down in front of the computer and spend the next few hours sifting through those digital files.

So, there I sat earlier today, looking at images filed in the 'Sponges' folder, and I found this photo. Looking first at the thumbnail image, it appeared to be a close-up photo of the surface of an orange sponge -- no more, no less. Then I loaded it into the photo editor to have a closer look at the full-screen version. Do you see what I saw?

There, peeking at the camera from an excurrent opening of the sponge is a little fish! (I can't decide whether the fish looks surprised or merely annoyed.)

The next surprise for me came when I looked up the numerical code in my log books. I was amazed to discover that I had taken this photo in 1990, during our first-ever dive trip to the Cayman Islands! According to my log book notes, that roll of film was shot at a place called Angelfish Reef, Grand Cayman.

I have no idea what species of sponge that is, nor do I know the identity of the little fish. My best guess is that it is some kind of Blenny. It's about the right size, and many fishes in that family like to hide out in small holes in the reef with only their heads visible to passers-by. In any case, we're glad to give him a new home in our underwater menagerie here on The Right Blue.

Oh, Baby! A juvenile Scorpionfish

by B. N. Sullivan

See that little fishie in the photo at right? It's a juvenile scorpionfish -- species unknown.

We came across this little guy in the Red Sea during a night dive at a place called Tiran Island, in the Straits of Tiran. (For those of you who may be a bit foggy on Red Sea geography, the narrow body of water that separates Egypt's Sinai Peninsula from Saudi Arabia is known as the Straits of Tiran. That is also where the Gulf of Aqaba joins the rest of the Red Sea.)

We were there to photograph other critters -- which we did -- but once we spotted this little baby, it became the highlight of our dive. I was kneeling on the sand, fiddling with camera settings. Jerry shined his light onto my camera so that I could see what I was doing. In the periphery of the pool of light, we saw something move. That something was partially covered with sand, but it had some colorful bits sticking out of it. It looked a little bedraggled, but we recognized that it was a tiny fish. Those colorful bits turned out to be its tail and pectoral fins.

This next photo shows how the little fish looked when we first saw it lying on the sand. Not quite two inches (5 cm) long, we knew it was some kind of fish, and that it probably was a juvenile. But a juvenile what??

Jerry slid his gloved hand under the little critter, picked it up, and held it out to me. We shined our lights on it to get a better look, when all of a sudden it wiggled, then fluttered, launching itself from the palm of Jerry's hand into the water column like a fledgling bird leaving its nest.

Luckily, I was able to snap a few frames of the fish as it glided back down to the sand (see first photo). By this time we were both quite sure it was some kind of scorpionfish, based on its overall shape, but to this day we do not know which species.

Our best guess is that it is a baby Bearded Scorpionfish (Scorpaenopsis barbatus), a species that is plentiful in that area of the Red Sea. The adults have an overall shape similar to the juvenile we saw and photographed that night. We have shown the photos of the juvenile to a number of people who know something about Red Sea fishes, but so far no one has been able to identify it with certainty. If any readers of The Right Blue happen to know the identity of this juvenile, please do let us know.

For reference, here is a photo of an adult Bearded Scorpionfish from the Red Sea. This specimen was photographed in the central Red Sea at Little Brother (Brothers Islands), where it was trying its best to blend into the reef scenery.

Video: Making of 'The Abyss'

One of our favorite sci-fi movies is The Abyss. This video gives an idea of why the film became known in the industry as "the toughest shoot in film history." The video runs for nearly 10 minutes -- much longer than the videos we usually post here on The Right Blue -- but it is both entertaining and informative, and we think it's worth the time it takes to watch.