Category Archives: invertebrates

Kawaihae’s hung over gobies

Marla, Hai, and I spent a relaxed Sunday morning snorkeling around the landing craft platforms in Kawaihae Harbor. We were hoping to see the black frogfish that Hai had been seeing on one of the pilings, or maybe the lionfish that he’d seen there a time or two, but we pretty much just saw the usual suspects: a handful of nudibranch species, Gorgonian Gobies, featherduster worms, Hawaiian Dascyllus, etc.

A thick wire hanging into the water from the second landing craft platform is home to several Gorgonian Gobies. It’s amusing to watch as they periodically dart out from their stations on the wire to to snatch  passing particles of plankton, but these fish are so small—just over an inch long— that it’s hard for my and Marla’s old eyes to make out much detail. (Hai sees everything with his seeming supervision.) Examining photos after we got home we noticed that the gobies have bloodshot-looking eyes—a lot like mine would look after a long night of drinking back in the day. Like this:

One of several Gorgonian Gobies under the second platform. Look at that bloodshot eye! Gorgonian Gobies, also known as Sea Whip Gobies, are easily confused with the similar Wire Coral Goby. The latter are a bit smaller, have a less pointed snout, and are less reddish in color. Wire Coral Gobies are found pretty much exclusively on wire coral, while Gorgonian Gobies will live on anything shaped more or less like a wire or thin stick.

More of the usual suspects—a handsome family of Hawaiian Dascyllus.

Hawaiian Whitespotted Tobies among the Halameda on the rubble at the base of the breakwater. These cute little endemic puffers are very common throughout the Islands. So is Halameda, a pantropical genus of green macroalgae.

A nice sized Painted Nudibranch on the march on one of the pilings. These, Trembling, and Gloomy Nudibranchs can almost always be found at this site lately.

“Big” nudibranchs and search images

I mean bigger than one inch.

Most of the nudis in recent posts have been less than an inch in length—some less than half an inch. This one from last week at Kawaihae Harbor is all of an inch and a half. It’s Dendrodoris krusensternii, a relatively rare species in Hawaii with no common name. Hai, that preternaturally skilled critter finder, found it crawling on a piling a couple of weeks ago and brought Marla, Sandra, Jeff, and me out to see it last week. We swam out to the pilings where Hai’d spotted the nudi, but at first none of us could find it. Luckily, I’d studied a photo of this thing that Hai had previously posted and I’d developed a pretty good search image*. A good search image—a visual idea of just what one is looking for—is really useful for spotting nudibranchs. Pretty soon I located this one on a partially dead Cauliflower Coral growing on a piling a few feet below the surface.

A Blue Dragon nudibranch from a dive earlier this month at a North Kohala site called Ulua. It’s about three inches long. We saw much larger specimens at Backside Molokini last year. These relatively active nudibranchs are supposedly quite common in Hawaii.

*Funny, if you Google “search Image” in 2019 you get a bunch of links telling you how to search for images on line. In this old guy’s world, the term means as described in this fascinating link:


We’ve been seeing a lot of interesting crabs lately. Or maybe we’ve just been paying more attention.  Reef-dwelling crabs form a diverse assemblage, filling a wide variety of ecological niches. Many, like shrimp, live symbiotically with other reef creatures. Most are quite attractive. Here are two that have posed for us over the last few weeks:

This crab is often called the Spotted Reef Crab, but here in Hawaii it’s more commonly referred to as the Seven-Eleven Crab. The latter name comes from the seven spots on top of the shell and four more on the bottom. These large crabs are mostly nocturnal, but on several occasions we’ve seen them while snorkeling at Mahukona during the day. All of our sightings have been in the late spring to early summer.  Perhaps this seasonality is related to mating activity. Seven-Elevens are found in many parts of the tropical Pacific. They’re eaten in many places, including Hawaii.

We found this Yellow-spotted Guard Crab hiding among the branches of an Antler Coral while snorkeling at Kihei in Maui. A handful of species of guard crab live mutualistically in branching corals.  As the name suggests, they protect the corals from intruders, including the predatory Crown of Thorns Starfish. In exchange for their protective duties the crabs get to dine on the corals—presumably in moderation so as to not destroy their hosts. Hoover writes that if you put your hand over a coral that harbors these crabs you will get your hand pinched. We didn’t try it.

Kawaihae south

At the south end of Kawaihae Harbor is a small boat marina where a couple dozen private sailboats are moored.  The marina is protected by a rip-rap breakwater that opens out into shallow, rather murky Pelekane Bay. The bay is known for its resident Black Tip Reef Sharks. Hai has seen and filmed these beautiful, harmless sharks on numerous occasions (see but as of last week Marla and I had yet to see them. In an effort to correct that situation, Hai and Lottie escorted us out through the marina into Pelekane Bay last week. We were successful in spotting these elegant, wary animals, but weren’t able to get any photos. We did, however, see and photograph some interesting creatures, both on the swim out through the marina and in the bay itself.

As soon as we entered the water at the marina Hai spotted this Wavy Bubble Shell actively crawling on one of the dock pilings. These unusual little mollusks are sort of halfway between snails and nudibranchs—they have shells, but cannot fit their whole bodies into the shells. Like many nudibranchs, they dine on toxic organisms (bristleworms in this case) and incorporate their prey’s toxins for their own protection. That’s what allows this delicate little animal to move around in plain sight. The pan-tropical species reaches a length of about 3/4 inch, which is about the size of this individual.

Just a minute or two later Lottie found this pair of Banded Coral Shrimp living on the underside of the dock. These shrimp, quite common in Hawaii and throughout the tropics, are usually found in pairs like this. They’re a type of cleaner shrimp, but are infrequently seen in the act of cleaning fish.  Hoover speculates that this is because they do most of their cleaning at night.

Out in the bay I ran into this Old Woman Wrasse. Hoover says this endemic fish is only common in the unoccupied Northwestern Chain of the Hawaiian Islands. We see them rarely at Mahukona; I posted a photo of a juvenile here:  An alternate common name for this fish is Blacktail Wrasse, but the black tail is only found on terminal males. The Hawaiian name for this large wrasse, Hinalea Luahine, means old woman. This fish’s face has—to me at least—an oddly humanoid look, but not necessarily old woman-ish.

Small stuff at Kawaihae

Last weekend Marla and I snorkeled at Kawaihae Harbor, inside the breakwater, south of the platforms where the Army landing craft tie up. This is a warm, calm, relaxing place to snorkel—shallow, no waves, little wind. It’s also kind of barren relative to the sites we usually snorkel, with lots of dead coral, but several different coral species. And, like most sites, it yielded some interesting stuff.

We always make sure to visit the huge Plate and Knob Coral (Porites monticulosa) head southwest of the platforms. Oddly, this coral and others of its type don’t seem to be very attractive to fish. This lonely juvenile Convict Tang and a small group of juvenile parrotfish were all that we saw on this one. The light here allowed the coral to show through the fish’s translucent fins.

Cauliflower Corals attract all sorts of fish. This tiny Hawaiian Dascyllus plays hide and seek among the branches. 

There were a couple of wire corals growing from the boat ramp just a few feet off the beach. One was occupied by this Seawhip Goby. (Hoover calls it Gorgonian Goby.)  Earlier this year our friend Hai found  a couple of these fish living on a wire—not a wire coral, an actual wire— that hung into the water from one of the landing craft platforms. Hoover writes that this species can also be found on waterlogged twigs and pretty much anything else shaped sort of like a wire. The similar Wire Coral Goby is apparently more selective, usually confining itself to actual wire coral.

Another record falls

Today Hai and Lottie were supposed to show us where the Blacktip Reef Sharks hang out at the south end of Kawaihae Harbor, but roaring offshore winds made us divert to Plan B. We went east to Kawaihae’s commercial docks, tucked away from the wind. There among the dock’s pilings we identified six species of nudibranch, breaking my short-lived personal record of five, set only three days ago.

After Marla and I got home I did a little web crawling and found that many nudibranch species are fond of vertical surfaces like those provided by Kawaihae’s pilings and pylons*. Who’d have thought.

These handsome, if not colorful, White Margin Nudibranchs are apparently quite common in Hawaii, but they were a first for me. Hoover writes that they are often found in small groups. We saw several pairs and a triple today.

This inch and a half long Gloomy Nudibranch was the only nudi we saw that measured over an inch. The species can reach three inches.

Here’s another Painted Nudibranch. Quite a contrast to the one shown in the last post. This species ranges all the way to the Mediterranean, which it apparently reached via the Suez Canal.

Another Trembling Nudibranch. Look at that supple body—the way it’s folded itself across the thin, stiff (at least by nudibranch standards) obstacle that it’s crawling over. This species is the only endemic in this post.

The White Bump Nudibranch looks quite a bit like the Trembling, at least to me. Not so much to Marla, who, unlike me, distinguished them instantly in the field. The colors of the gills and rhinophores—deep blue in the Trembling; pale grey and brown in the White Bump—are the main identifiers for me. Marla said it was more of a Gestalt thing for her. The body color difference so apparent in these flash photos was not nearly so apparent to me in the rather dim light around the pilings.

This was the highlight of the outing for me. It’s a member of the genus Caloria; maybe an un-named species or maybe indica. There’s a lot of confusion on the web regarding this. In either case, gorgeous but tiny and surprisingly hard to spot. We saw several—mostly spotted by Hai. (I don’t know what that little round thing below the nudi is, but I suspect it’s something planted by ancient aliens. Click and take a close look and I’m sure you’ll agree.)

*Actually, they’re all pilings. I’m really misusing the term pylon here, but we** use it anyway to refer to the piling supporting the military platforms. Actually, we’re misusing piling as well. A pile is a support column, while a piling is a structure composed of piles. Piling feels better somehow, maybe because it’s doesn’t sound like a hemorrhoid.

**By “we” I mostly mean Jeff and me.

Kawaihae impresses again

Yesterday Marla and I, along with our friends Hai and Lottie, visited the huge concrete platforms that the military landing craft tie up to in Kawaihae Harbor. Hai had messaged me the other day that the nudibranchs had returned to the massive concrete pylons that support the platforms. Last July I posted on the surprising variety of nudibranchs and other interesting invertebrates living at this unlikely location. ( The nudis disappeared over the winter, but they’ve returned, seemingly in greater abundance and diversity than we’d seen last summer.

We spent over an hour free diving among the pylons, finding nudibranchs and other good stuff as deep as twenty feet, where the pylons hit bottom. We identified five different species of nudi—Gloomy, Painted, Trembling, Decorated, and Kahuna.  I’d seen and posted photos of the first three species in July, but the last two were new to me.  I struggled with my little Olympus point’n’shoot camera, having inadvertently gummed up some settings, but still managed to get some recognizable shots.

This little Trembling Nudibranchs has bunched itself up into an ovoid shape in contrast to the more elongated proportions this species more commonly assumes.

A gorgeous Decorated Nudi.

A tiny Painted Nudibranch that Lottie found drifting next to the pylons. She held it in her hand for me to photograph. I’d seen and photographed this species before, but the individual I’d previously seen was much less conspicuously marked than this one. This one looked so different from the earlier one (and from the illustration in Hoover’s Hawaii’s Sea Creatures) that I initially doubted Hai when he called it a Painted. A little web research when I got home revealed that Hai was correct. Discussing it later, Hai and I agreed that this is an unusually variable species.

This was the hit of the trip for me—a Kahuna Nudibranch. The little fellow, around fifteen feet deep at the base of a pylon, was maybe half an inch long. That color made it fairly easy to spot though. None of the nudis in this post were longer than an inch.