Kwajalein's Marine Life
(the video)
Kwajalein Atoll in the Marshall Islands is the largest coral atoll in the world, but otherwise is a
reasonably typical atoll. It has a roughly boomerang-shaped ring of mostly shallow reef bearing
small, usually elongate islands called "motus" surrounding a lagoon that probably averages
around 50 meters (about 165 feet) deep and maxes out at a depth of about 61 meters (200 feet).
Although much of the reef rim is exposed at very low tides, other parts, particularly along the
western reef, are deeper, maybe 5 to 10 meters below the surface. Interspersed along both sides
of the atoll are deep water passes, cuts in the reef that range from depths of about 15 to over 50
meters. Currents rush in and out these passes and low points in the reef during tidal changes.
The deep lagoon bottom varies from fine sand to beds of calcareous Halimeda and other algae to
heavy coral, often thin and plating species that spread out to catch the dim light reaching the
depths. Scattered throughout the lagoon, most abundantly on the lagoon sides of deep water
passes, are shallow lagoon pinnacles, often flat-topped reefs that rise like mountains from the
lagoon floor.
The lagoon and seaward reefs and pinnacles are often densely covered with rich and diverse
coral reefs containing seemingly innumerable species of fish and invertebrate animals. This
DVD, like the others in the series on the underwater world of Kwajalein, shows just a few of the
many creatures that make up Kwajalein's marine life.
The DVD is roughly divided into three parts. The first shows scenes typical of the seaward reefs,
reefs on the east and west sides of the atoll that face the ocean. These are locally called
"oceanside" reefs. The second part covers lagoon pinnacles, locally known as "coralheads,"
although technically a coralhead can be any clump of coral. The last part shows the life of lagoon
rim reefs, algae patches and sand flats. A black title in the upper left corner indicates the start of
each of these sections.
This DVD is entirely set to music with no narration. However, after the initial title, each scene
has a white subtitle that can be turned on or off if desired on most modern DVD players. By the
nature of the background images, sometimes the subtitle does not show up too well. The subtitles
are the keys that can be used to find out more information about each scene. A short description
of each scene follows in the remainder of this document. The bold heading on the left side of
each paragraph below is the subtitle from the scene. For many scenes, the scientific name of the
animal shown is listed on the right side in italics. To read more about any scene, turn on the
video subtitles and search through this document for the particular title.
The subtitles are useful for finding out more about what the scene shows. However, we find it
most enjoyable to watch the video and listen to the music without viewing the subtitles, just
enjoying the sights and the sounds.
The material in this DVD was filmed entirely at Kwajalein Atoll, with the exception of just a
couple of scenes from Namu Atoll, the first atoll south of Kwaj. The excellent music is all by
Ashley and Franks from their CDs Forest Dreams, Naturecise 1, and Naturecise 2, and is used
with their kind permission.
Oceanside
(Title Scene - no subtitle)
On a calm day, you can look up through the surface of the water and see the shape of the clouds.
Diver swims to dropoff
In most areas, the seaward reef on the western side of the atoll slopes gradually out from the
intertidal reef to a depth of about 5 to 10 meters, then drops steeply over the edge on a 60 degree
or sometimes steeper slope. This area is exposed to the open ocean swell, which periodically gets
large enough to break off coralheads and roll them around, causing considerable damage.
Consequently, many of the larger coral colonies out here are the stronger, more massive species
that can withstand the occasionally rough conditions.
Diver descends past outcrop
This large outcrop of rock surrounded by gorgonians is on the steep seaward reef slope.
Diver above through whip corals
Looking back up the seaward reef slope towards the surface. In some areas, the gorgonians and
whip corals are abundant and provide refuge to innumerable small fish.
Sponge and soft corals under ledge
The light gray sponge in lower center is Cribrochalina olemda. The fans in the front are
gorgonians and the bush behind is an Antipatharian black coral. Occasionally, ledges on the
seaward slope are loaded with life.
Soft and fan corals in ledge
The soft coral Chironephthya is in front, with the gorgonian Anella mollis is behind and just
below. There are other gorgonians, pink corals, and yellow corals scattered about in the scene.
Soft coral
Scleronephthya sp.
This soft coral is growing on the floor of a small cave on the steep seaward slope.
Soft coral hanging from overhang
Chironephthya sp.
A soft coral hangs from an overhang while a diver approaches in the distance. A couple of
crinoids are on a gorgonian just outside the overhang.
Soft coral
This is a closer shot of the previous scene.
Soft coral
Chironephthya sp.
Dendronephthya sp.
Dendronephthya soft corals come in a variety of colors. This soft coral is common at islands
farther west, such as Pohnpei and Chuuk, but is not particularly common at Kwajalein. It is
found a bit more often in areas swept by regular currents.
Soft coral
Dendronephthya sp.
This soft coral comes in a variety of colors. This one happens to be especially large and dark red.
Spiny brittle stars hide among branches. On rare occasions, we have come across single colonies
of this soft coral more than a meter and a half tall.
Diver behind soft coral
Dendronephthya sp.
A diver swims up behind a large light pink Dendronephthya. These soft corals seem to grow
quickly and apparently do not last long. Large colonies are rare, and usually when we return after
a few months to look at one again, it is gone.
Red gorgonian
Acabaria sp.?
Gorgonians are often rather difficult to positively identify. Many of our names are guesses, based
on similarity to photos in some of the invertebrate guide books. This gorgonian is a relative large
species living on the steep seaward slope. Sometimes the white polyps retract, leaving only the
red branches visible.
Longnose hawkfish
Oxycirrhites typus
These usually live in gorgonians and soft corals on steep slopes. This one happens to be resting
on Halimeda algae at the base of a gorgonian. Here at Kwajalein they always seem to be rather
deep, 30 meters (about 100 feet) or more. We have seen these at Pohnpei as shallow as about 9
meters (about 30 feet).
Colin’s angelfish
Centropyge colini
This rare pygmy angelfish lives on the steep seaward slope, usually in areas that have sheer walls
and small caves.
Ornate angelfish
Genicanthus bellus
This is the male form of this seldom seen, medium-sized angelfish. It too appears to live only on
the steep slope, where a single male is usually accompanied by several females. The female has
black bands on a blue gray background.
Longfin anthias
Pseudanthias ventralis
Fairy basslets is another common name for this group of fish. Both male (with the red back) and
female (yellow back) fish are shown here. This species is seldom seen, usually deep enough on
the steep seaward slope that the bright colors are at best subdued. It takes artificial light to see
them in all their glory.
Brittle stars all over gorgonian
Ophiothrix sp.
This small gorgonian is infested with long-armed brittle stars that probably compete with the
coral for planktonic food. These particular brittle stars are covered with long sharp spines that
can cause a painful sting.
Spiny brittle stars on gorgonian
Ophiothrix sp.
A closer shot of the previous scene shows the spiny armament on the long, curling brittle star
arms.
Brittle star in red gorgonian
Ophiothrix sp.
A single brittle start intertwines among the long branches of a red gorgonian. There are a number
of different brittle stars that seem to be found only on various gorgonians.
Feather star on sea fan
In the same class as brittle stars (the Echinoderms), feather stars also frequently perch on
gorgonians to get good exposure to plankton in the water flowing past. These many-armed,
brittle echinoderms are often referred to as crinoids, a word that comes from Crinoidea, the name
for the group. This one is on a red gorgonian (probably Melithaea).
Feather star on sea fan
Here is another crinoid on a different red gorgonian (probably Acabaria).
Electric clams
Lima ales
These clams live in holes in the steep seaward reef. They continually extend their tentacles and
flash what appears to be an electric arc from the animal between the shell valves. Actually, it is
just the bright white inner edge of the clam’s mantle, which it waves in and out of view.
Nudibranch
Phyllidiella sp.
This possibly unnamed nudibranch is known from only a few specimens from the seaward slope.
Few nudibranchs have common names. Most of those used here are invented. In some cases, a
common name can be derived from the meaning of the scientific name. Nudibranchs in this
group, the Phyllidiids, are the ones most likely to be seen crawling about in the open during the
day at Kwaj. They are all highly toxic and their distinctive color patterns probably warn potential
predators to stay away.
Fissured nudibranch
Phyllidiella fissurata
This is another highly toxic phyllidiid nudibranch with a roughly similar coloration to the last
one. The camera pans slowly from the anterior to posterior the posterior end. The two black
pointed tentacles on the upper left side of the animal are the rhinophores, organs basically used
to smell the water passing by. Most nudibranchs use chemical senses to detect the presence of
food and probably mates. Phyllidiid nudibranchs all eat sponges.
Kunie’s nudibranch
Chromodoris kuniei
This nudibranch is one of the chromodorids, literally "colorful dorid" nudibranchs. Most
chromodorids are very soft bodied. This species flaps its mantle margins up and down as it
crawls. It is found sporadically on the seaward slope. Chromodorids are also highly toxic, and
their bright colors and patterns are thought to be used as warning coloration, a signal to predators
that these are not good to eat.
Kunie’s nudibranch
Chromodoris kuniei
Here is a closer view. Again, the pair of chemosensory rhinophore tentacles extend upward from
the left side of the animal, and a tuft of exposed gills waves closer to the right side of the back. It
is this "naked" gill that is the basis for the name nudibranch. The pink substrate the nudibranch is
crawling on is a colonial tunicate. The white patch within the dark purple thin but pointy sponge
at right is a spot of bare rock where the nudibranch had just grazed off the sponge.
Red nudibranch
Dendrodoris sp.
Here the rhinophores are on the left side and the gills on the right. Dendrodorids are also toxic
sponge eaters.
Carbuncle nudibranch
Dendrodoris carbunculosa
This is a very large nudibranch, 250mm or more in length. It lives on seaward and intertidal
reefs, and is nocturnal. It has a smooth, slippery, rubbery feel.
Red and green nudibranch
Nembrotha kubaryana
This species has fiery red color to the rhinophores, gills, and foot margin. The body has green
spots on jet black. The green varies in shade between specimens; sometimes it is so dark it is
hard to see. But overall, this nudibranch is hard to miss. It is usually 50 to 75mm (2 to 3 inches)
in length, and the red coloration can be almost painfully bright. It too is poisonous to eat and
often is exposed during the day, so its color probably functions to warn predators.
Red and green nudibranch
Stretching from rock outcrop to algae.
Nembrotha kubaryana
Chooch or blue dragon nudibranch
Pteraeolidia ianthina
This nudibranch is sporadically common and is one of few to be exposed during the day. The
tentacles vary from blue to brown and contain symbiotic zooxanthellae, single-celled plants that
photosynthesize and provide the nudibranch with some oxygen and food. This well-known and
easily recognized nudibranch is one of the few with a valid common name; unfortunately, it has
several common names depending on where they are observed.
Chooch or blue dragon nudibranch
Pteraeolidia ianthina
Three elongate specimens of the same species as in the previous scene crawl over a rock. This
species eats hydroids and stores the stinging cells (nematocysts) of their prey in their dorsal
tentacles, making the nudibranch as capable of stinging as the hydroid. These elongate
nudibranchs measured over 100mm (about 4 inches) long.
Lanceolate egg shell on red whip
Aclyvolva lanceolata
This member of the egg shell family is always on its prey, the red whip gorgonian (Ellisella). As
you can see, it blends in quite well. Whenever we see these, there is always only one specimen
on a particular colony of the gorgonian. So they must have to crawl to the base and across the
reef substrate to meet up and mate. But I suppose with the red whips are as thick as you can see
in the background of this photo, that would not be too hard to do.
Lanceolate egg shell on red whip
Aclyvolva lanceolata
In this scene, the mollusk’s orange shell is partially exposed. The shell here is nearly 25mm (1
inch) long.
Golden cowry
Lyncina aurantium
Another seaward reef slope dweller, this cowry is nocturnal and hides well back in ledges and
caves during the day. At night, it wanders about the reef to feed. Here, its camouflaging mantle is
partly extended, covering half of the shell. A snail’s mantle is the organ that actually produces
the shell, laying down calcium carbonate pulled from food and from the water. In most snails,
the mantle just adds shell material to the outer lip, but in cowries and some other naturally shiny
species, the mantle covers the entire shell, keeping it pristine and free from growth.
Golden cowry
Lyncina aurantium
Disturbed by the video lights, this specimen has retracted its mantle into the shell. It crawls into a
hole to escape the lights. These cowries are typically about 90mm (a bit over 3 and a half inches)
long. The little specks swirling around erratically in the field of view are small planktonic shrimp
attracted to the bright video lights at night.
Red stinging anemone
Phyllodiscus semoni
Although this looks like nothing more than a red lump, it is actually a cryptic sea anemone. We
have seen this species in red, green and brown. This is the only red one we have come across.
This anemone is rarely seen, but that is probably mostly because the brown and green ones are
difficult to distinguish from rocks and algae.
Red stinging anemone
Phyllodiscus semoni
At night or when disturbed, tentacles that pack a powerful sting extrude from the center. This
anemone was probably about 200mm ((roughly 8 inches) in diameter.
Red stinging anemone
The close view of this anemone shows the curling tentacles.
Phyllodiscus semoni
Twostripe clownfish in crispa anemone
Amphiprion chrysopterus / Heteractis crispa
The anemone Heteractis crispa is most common on the seaward reef and rare in the lagoon. This
clownfish (more correctly referred to as an anemonefish) is also sometimes called the orangefin
anemonefish and is the typical inhabitant of H. crispa and the most frequent inhabitant of the
carpet anemone (Stichodactyla mertensii). In the Marshalls, this clown is distinguished by two
white or bluish white bands and a white or translucent tail. Young specimens may have a
brownish tail and can be confused with young threestripe clownfish (Amphiprion tricinctus).
Twostripe clownfish in crispa anemone
Amphiprion chrysopterus / Heteractis crispa
Usually a pair of adult twostripe clownfish inhabits a particular anemone, and there may also be
one or two small juveniles. When the young ones get large enough to be considered competition,
they are chased off by the adults to find their own anemone. Most probably do not survive. The
number of suitable anemones is the limiting factor on clownfish populations, and you virtually
never see a clown without an anemone. The large clown here knocks a wentletrap mollusk
(Circostrema varicosa) off the rock. The wentletrap is a parasite or predator on the anemone.
Twostripe clownfish in crispa anemone
Amphiprion chrysopterus / Heteractis crispa
This anemone is usually brown or yellow brown, but the tentacles are often tipped with a spot of
pink or purple. In this unusual specimen, a good chunk of the end each tentacle was purple.
Twostripe clownfish in crispa anemone
Amphiprion chrysopterus / Heteractis crispa
Anemones, like corals, giant clams and a few nudibranchs, host symbiotic zooxanthellae algae
within their tissues. In addition to using carbon dioxide produced as a waste product by the
anemone, the zooxanthellae provide its host with oxygen and food from photosynthesis. It is this
mutually beneficial relationship that enables a coral reef to exist and be the foundation for an
extremely diverse ecosystem. Sometimes, though, the anemone (or coral) may expel the
symbiotic algae, leaving, as it has in this case, a nearly all white animal. When this happens, the
purple tentacle tips really stand out. This "coral bleaching" has gained some notoriety in recent
years as waves of bleaching in some areas have damaged or killed many corals, and many
suspect the ultimate cause is the warming of the oceans. So far at Kwajalein, we have seen only
one episode of serious coral bleaching (in 2009) and it fortunately affected only a few coral
species. However, we have seen anemone bleaching also in response to being too long without
sunlight (if, for example, a broken table coral falls into a position to shade the anemone all the
time).
Twostripe clownfish in carpet anemone Amphiprion chrysopterus / Stichodactyla mertensii
The carpet anemone lives in both lagoon and seaward reef habitats attached to a hard substrate.
Adult anemones have large disks bearing short tentacles, and the disk usually spreads out over
the bottom. Most often, these anemones are occupied by two adult and perhaps two or three
juvenile twostripe clowns.
Twostripe clownfish in carpet anemone Amphiprion chrysopterus / Stichodactyla mertensii
The twostripe clown lives in most specimens of carpet anemones. Most of these anemones are
some shade of brown, again due to the color of their symbiotic algae. Note how the clownfish is
able to nestle right down among the tentacles of the anemone. Anemones, like their coral and
hydroid relatives, possess stinging cells called nematocysts that keep most fish at bay.
Nematocysts are sort of like coiled springs that trigger upon contact and force a tiny venomous
harpoon into whatever they come into contact with. Clownfish, however, do not get stung.
Twostripe clownfish in carpet anemone Amphiprion chrysopterus / Stichodactyla mertensii
This is a closer view of the same species as in the previous scene. While the stinging cells of the
anemone can injure or kill most fish, clownfish do not seem to be affected. Studies have
indicated that the fish develop a coating of mucus over their bodies that inhibits the discharge of
the anemone’s stinging cells. This is substantiated by the habit of an clown that has been
deprived of an anemone for some time (in an aquarium for example) to very gradually
acclimatize back to its host by repeated briefly touching the tentacles. It is thought that this
behavior stimulates the production of the protective mucus. This relationship between some
species of anemones and clownfish is called symbiosis, literally "living together." Clownfish are
always found in anemones, and certain species of anemones are never found without clownfish.
There must be some advantage to the partnership. And there is. The stinging cells of the
anemone help protect the clownfish from predators who wish to avoid being stung. And the
aggressively territorial clownfish will chase away some coral and anemone-eaters such as some
species of butterflyfish. The relationship is advantageous for both clowns and anemones; such a
symbiotic relationship is often called a "mutualistic" one.
Two kinds of clownfish in carpet anemone
It is rare here at Kwaj for a single anemone to host two different species of clownfish, but it does
happen sometimes. Here, a single small dark threestripe clownfish (Amphiprion tricinctus)
shares a carpet anemone (Stichodactyla mertensii) with a couple of twostripe clowns
(Amphiprion chrysopterus) It looks as though they do not get along all that well. Even though
clownfish usually don’t share anemones, frequently there will be one or more anemone-dwelling
three-spot damsels sharing anemones with various clowns.
Threestripe clownfish in carpet anemone
Amphiprion tricinctus / Stichodactyla mertensii
This is a single young clownfish in a small carpet anemone. Actually, this clown might be
incorrectly identified. Young specimens of Amphiprion tricinctus and A. chrysopterus often look
very similar. One characteristic of Amphiprion chrysopterus is supposed to be orange pelvic fins,
but on this specimen, the large fins are mostly brown and only tipped with orange. It makes it
tough to be sure about this one.
Threestripe clownfish in carpet anemone
Amphiprion tricinctus / Stichodactyla mertensii
This clownfish comes in two distinct color forms. When the fish lives in a carpet anemone such
as this one, the fish is mostly black with three (rarely two) white stripes. Fish that live in the
common bubble anemone (Entacmaea quadricolor) have a lot of orange over much of the
anterior portion of the body, which will be shown in scenes later in this video. An adult
Amphiprion tricinctus is easily distinguished from A. chrysopterus by its black tail. Note that the
black color in these threestripe clowns in carpet anemones seems to take a while to develop. In
part of this scene, we get a glimpse of a small juvenile clown that is still orange and white. As it
grows, the orange will turn black.
Threestripe clownfish in carpet anemone
Amphiprion tricinctus / Stichodactyla mertensii
Here is another pair of the black morph of Amphiprion tricinctus in a carpet anemone. Later in
the scene, a yellow lemon peel angelfish (Centropyge flavissima) comes out of a hole before
turning around to go back in.
Young lemon peel angelfish
Centropyge flavissima
Young specimens of this species usually have a dark spot, sometimes ringed with blue, on the
side of the body. The spot fades with age, disappearing in adults. In this one, the spot is fading.
Young lemon peel angelfish
Centropyge flavissima
This smaller lemon peel angel has a more distinct side spot. This one lives among the branches
of the crinkly coral Porites rus.
Herald’s and multicolor angelfish
Centropyge heraldi / Centropyge multicolor
The all yellow angel is Centropyge heraldi and the white one with yellow, blue and black
markings is Centropyge multicolor. The multicolor lives only on the seaward slope, while
Herald’s can be found on lagoon reefs and pinnacles as well. The multicolor tends to be deep.
Rarely do you see one shallower than about 20 meters (about 65 feet).
Flame angelfish
Centropyge loricula
The flame is most common on the seaward reef, usually living from near the knee of the dropoff
to depths of about 25 meters (about 80 feet) on the slope. On occasion, it might be found on a
lagoon pinnacle. This one is at the upper edge of the seaward reef, swimming among the spires
of a colony of Porites rus coral.
Griffis’ angelfish
Apolemichthys griffisi
This angel is rare in the Marshalls, so far known only from a few specimens observed in the
vicinity of the Shark Pit at the western end of Kwajalein Island. This area boasts a number of
unique species at Kwaj that we have seen in no other part of the atoll. Unfortunately, as I write
this, the area has been off limits to diving for several years, since the discovery of some
unexploded ordnance (UXO) left over from the invasion of the island during World War II.
Although the UXO was blown up and destroyed by ordnance disposal personnel a couple of
years ago, the area still has not been opened up for diving again. Rules on a military base seem
highly resistant to change.
Emperor angelfish
Pomacanthus imperator
The emperor is the largest angelfish in the Marshalls. It lives on both lagoon and seaward reefs.
This one was in a ledge with some colonies of pink Stylaster coral on the ocean side of Gehh
Island. These fish can get very vocal, emitting a series of loud grunts if a diver approaches too
close.
Moorish Idol
Zanclus cornutus
Moorish idols are common on lagoon and seaward reefs throughout the atoll. Primarily a sponge
eater, they tend to not do well in an aquarium. While some will learn to eat other foods, they
seem to not get what they need and get skinnier and bonier-looking until they finally die.
Swimming flatworm
Pseudobiceros fulgor
Although flatworms are benthic invertebrates, occasionally you can see some species swimming
up off the bottom by undulating their lateral margins. This is one of the larger Kwaj flatworms,
sometimes reaching up to about 100mm (4 inches).
Blackstripe flatworm
Pseudobiceros gratus
This common mostly white flatworm is distinctive with its longitudinal black bands. This one
usually lives under rocks, but can occasionally be seen crawling about in the open.
Orangemargin flatworm
Pseudobiceros periculosus
This uncommon flatworm is black with a distinct orange margin. It is another of the longer larger
species and will swim if disturbed.
Whitestripe flatworm
Pseudobiceros sp.
This species is tan with a white margin and black submargin, and a longitudinal middorsal white
line bordered on both sides by black. It is medium sized, up to about 50mm (2 inches) and is
rather rare.
Maroon flatworm
Pseudoceros sp.?
This maroon animal finely speckled with white and scattered larger white spots is probably a
species of Pseudoceros.
Spotted flatworm
Pericelis sp.
This flatworm, with its distinct brown color with oval lighter spots, is mostly found under rocks
in shallow on the top of the seaward reef. It has also been seen on lagoon pinnacles.
Yellowbump flatworm
Thysanozoon sp.
This flatworm must be distasteful or poisonous. It is usually found crawling about in the open
during the day, where its black body, white margin, and back covered with yellow-tipped
projections, is hard to miss. This is another species that will often swim when disturbed.
Whiteline flatworm
Maiazoon orsaki
This one is brownish with a thin white middorsal line, black margin, and red submargin. It swims
up near camera lens at the end of the clip. The dark green and yellow on the substrate are
encrusting sponges growing on the undersurface of a rock.
Spiral-gilled tubeworm
Spirobranchus giganteus
All you ever see of this kind of worm is the double spiral of colored branches extending from the
reef. The branches function both for breathing (providing a large surface area to facilitate
absorption of dissolved oxygen from the surrounding water) and for planktonic food collection.
They come in a variety of colors. Here a blue one emerges from a hole in live Porites coral, the
coral this species seems to prefer at Kwaj. They are quick to retract into their holes when
disturbed.
Spiral-gilled tubeworm
Orange and white specimen.
Spirobranchus giganteus
Spiral-gilled tubeworm
Yellow with a brown core.
Spirobranchus giganteus
Spiral-gilled tubeworm
Spirobranchus giganteus
Mostly greenish gray with white tips to the gill feathers and a pinkish core.
Spiral-gilled tubeworm
White at the base, turning mostly maroon toward the spiral tree tops.
Spirobranchus giganteus
Spiral-gilled tubeworm
Mostly brownish maroon with white mottling.
Spirobranchus giganteus
Spiral-gilled tubeworm
Spirobranchus giganteus
Light mottled greenish and white with light salmon-colored tips. The object in the front is the
operculum, a trap door the worm uses to close off its hole when it retracts inside.
Spiral-gilled tubeworm
Spirobranchus giganteus
Complex pattern of maroon and yellow.
Spiral-gilled tubeworm
Combination of maroon, yellow and white.
Spirobranchus giganteus
Spiral-gilled tubeworm
Spirobranchus giganteus
Sometimes they cluster together in one colony of living coral. Rarely are any two exactly alike.
Orange-spotted or longnose filefish
Oxymonacanthus longirostris
Usually these are found in pairs. It seems when more than two get together, they spend a lot of
time bickering. These fish eat exclusively living coral, so despite their gaudy colors, interesting
shape and amusing antics, they are not well suited to the home aquarium. Their live coral food is
very hard to keep in a tank.
Orange-spotted or longnose filefish
Oxymonacanthus longirostris
This large individual (for its species) gets chased away by a damsel protecting its turf. The
damsel is the rather aggressive jewel damsel, Plectroglyphidodon lacrymatus.
Mimic filefish
Paraluteres prionurus
Two individuals interact. These are called mimic filefish because they closely resemble a
sharpnose puffer, Canthigaster valentini. The puffer is very toxic and not edible, and the
mimicry probably helps protect the file as well. The larger one appears to be displaying to the
smaller one.
Mimic filefish
The are most common on the seaward reef.
Paraluteres prionurus
Barred filefish
Cantherhines dumerilli
This is called the barred filefish because a close examination of the dark side reveals vertical
black bars. They are not visible in the video. This species feeds by biting off chunks of live coral
with its strong white teeth.
Mustache triggerfish over eggs
Balistoides viridescens
During nesting season, this trigger defends nest by hovering over it to keep egg eaters away. It
darts away for a few seconds at the approach of a diver, but quickly returns to its guard duty.
During nesting season, this large trigger is apt to attack divers who, usually inadvertently,
venture too close to their nests. Some people have been rammed or bitten without even noticing
the trigger's aggressive behavior. One person was even bitten on his cheek. The trigger reaches
more than a half meter (more than 19 inches) in length. They truly can do some damage to a
diver, so it is best to be alert. The triggers seem to mostly brood their eggs at around the same
time, so if you see one of these triggers hovering mouth down for an extended period, it is best to
give them some space. This trigger's common name comes from black, mustache-like marking
above the mouth, but it is also commonly called the titan triggerfish.
Mustache triggerfish over eggs
Balistoides viridescens
Same as previous. They often hover face down over the eggs and fan them by wafting forward
currents of water using their pectoral fins. If they leave the eggs for even a few seconds,
opportunistic fish like wrasses and damsels will dart in to eat them. It's a tough life for a mama
mustache.
Mustache triggerfish
Balistoides viridescens
These triggers eat a variety of marine invertebrates, and will break up bushes of coral by biting
off the branches one at a time to get at the crabs and small fish hiding within. They will also turn
over fairly large rocks and “blow” in the sand (using their pectoral fins again) to dig out worms
and other potential prey. This one looks as though it is being hassled by a group of wrasses that
appear to want to clean it—pick any parasites off its body. Sometimes the parasite pickers pick a
little too hard, irritating their cleaning clients.
Wedge triggerfish
Rhinecanthus rectangulus
This shallow water trigger is being cleaned by the cleaner wrasse, Labroides dimidiatus.
Clown trigger being cleaned
Balistoides conspicillum
The clown trigger is one of the most conspicuously colored of fish. At one time, living
specimens brought high prices when shipped to aquariums in Japan, Europe, or the US.
However, it can be very aggressive in an aquarium. Most of the individuals seen out on the reef
are large. The small juveniles tend to settle out and grow up in deeper water, moving shallower
as they get larger. This one is being cleaned by the cleaner wrasse, Labroides dimidiatus. Being
cleaned is apparently advantageous to the cleaning client; most fish will not only not eat a
cleaner but will remain motionless while the cleaner works them over. Some fish, even large
predators, allow the cleaner to go inside the mouth and gills to pick at parasites.
Clown trigger
Balistoides conspicillum
This one comes from behind rock to look at the photographer. It turns and erects its dorsal spine.
The small purple fish in front are young purple queens (Pseudanthias pascalis). This particular
trigger was caught as a rather small specimen and was raised in a large aquarium for several
years. When it finally started to get too large for the tank, we released it on a reef we visit
occasionally. We continued to see the fish for several years after its release in the same place,
and it typically allowed us to get closer to it than most "wild" clown triggers.
Clown trigger school
Balistoides conspicillum
Clown triggers are usually solitary, but must come together to mate. Rarely, though, do you see
more than two at a time.
Stripebelly puffer aggression
Arothron hispidus
Younger specimens tend to have more prominent stripes on the belly, hence the common name.
These can often be seen on seaward reefs hanging up in the water column well above the reef. It
is a medium-sized puffer; a good-sized one is about a third of a meter long (about a foot)
although some can get a bit larger. Here two individuals appear to display some aggression
towards one another.
Guineafowl puffer
Arothron meleagris
This black puffer with white spots primarily eats living coral, chunks of which it bites from coral
colonies with its sharp, hard beak-like teeth. The algae waving around in the surge is
Asparagopsis taxiformis.
Blackspotted puffer
Arothron nigropunctatus
A more common color form of this species is mostly gray. The yellow ones are unusual. But all
color forms of this species have the scattered discrete black spots, although often fewer than
sported by this one. The coral at upper left is fire coral (Millepora) and the pinnacle of coral
coming up at right is Porites rus.
Stellate puffer
Arothron stellatus
These are the largest puffers at Kwajalein and inhabit both seaward and lagoon reefs. Often they
are not too wary of divers. Fortunately, they are not aggressive. Those hard, sharp, beak-like
teeth could do damage if the fish was inclined to inflict some. These have been reported to eat a
variety of invertebrates, including corals, sponges, sea urchins, starfish, hermit crabs, and larger
crabs. The latter might fight back; often you see the mouths of larger puffers kind of torn up, as
if a crab had physically objected to being eaten. The books report these to reach at least 90cm,
which is not too far away from 3 feet long. I believe it. It is not hard to see large ones out in open
water off the reef, slowly drifting by like large dirigibles.
Spotted boxfish female
Ostracion meleagris
This is a medium-sized boxfish found on a variety of Kwaj reefs. This is the female, all black
with white spots.
Spotted boxfish male
Ostracion meleagris
The male spotted boxfish is colored like the female on most of the top, but it has a large orange
patch between its eyes and its sides are blue with orange spots. Like most of the boxfish, these
can release a toxin when disturbed that will kill any other fish (and often the boxfish as well)
when left in a closed system such as a bucket or an aquarium. If collected and treated very
gently, they can be introduced into and kept in an aquarium, but not one in which they will be
harassed, or the entire aquarium might die.
Gravel gobbler gobies
Valenciennea strigata
These gobies are usually paired and can often be seen scooping up mouthfuls of sand, which they
process for organic material, either spitting out the remaining sand or letting it drop out through
their gills. They will usually dart into holes when approached.
Tile blenny
Escenius opsifrontalis
These small blennies are often found on the upper edge of the seaward reef, where they perch on
sides of rock walls and in small ledges. This one snatches a bite of some passing food.
Shrimp pair on anemone
Periclimenes brevicarpalis
These two shrimp live on a sticky sucker anemone, Cryptodendrum adhaevisum. These
anemones deserve their common name; the low tentacles are very sticky to the touch, and the
entire anemone will suck down into a hole if disturbed.
Shrimp on anemone
Periclimenes brevicarpalis
This shrimp on is also on a sticky sucker anemone (Cryptodendrum adhaevisum). These
anemones come in a variety of colors. This particular species of shrimp is mostly translucent to
transparent, except for large white spots. They are always associated with one of several species
of sea anemone.
Shrimp pair on anemone
Periclimenes brevicarpalis
Again, two shrimp are on a small, white sticky sucker anemone (Cryptodendrum adhaevisum).
The larger shrimp is usually the female. The anemone here has lost all its color, which comes
from the single-celled plants called zooxanthellae that the anemone (and many other corals and
their relatives) harbor within their tissue. Usually, losing the zooxanthellae, called "coral
bleaching," is caused by higher than usual water temperature or prolonged lack of sunlight.
Shrimp on feather star
Periclimenes amboinensis
This commensal shrimp is always found living on a feather star, or crinoid.. The shrimp varies in
color, usually to match the host. In this specimen, yellow bands on the shrimp closely match
those on the crinoid.
Whip coral shrimp pair
Pontonides ankeri
This particular shrimp is always on the whip-like black coral called Cirripathes. It usually takes
a pretty close look to spot them.
Longarm glass shrimp
Periclimenes tenuipes
This nearly transparent shrimp has long arms with long delicate pincers. They are often found
near anemones or corals.
Spotted box crab
Calappa calappa
We call these the Darth Vader crabs because the carapace (shell) looks like the evil Jedi's helmet.
They are variable in color from white to orange to spotted. Usually they remain buried in sand by
day, so this one tries to bury again quickly when exposed to light. Notice how it uses its large,
flat pincers (called chelae) to push sand away as it sinks downward. Its powerful pincers are used
to break up the shells of mollusks, their main prey.
Brown & white walking crab
This is one of many unidentified species of xanthid crabs from the Marshalls. The word xanthid
comes from the crab family Xanthidae. Crabs are highly prized meals for many predatory fishes,
so whenever one gets exposed like this, it quickly tries to find a way to get under cover again.
Alien crab
Another unidentified crab. I think it looks like some bulbous-headed alien from an old science
fiction movie. This one is small, less than 20mm in width.
Red & white walking crab
This striking crab is another unidentified species. It too seeks a way to hide before it gets picked
off by a predator.
Spiny decorator crab
Hyastenus bispinosus
This long-legged crab has two spines on its head that it often decorates with hydroids and other
debris.
Hermit crab in murex shell
This is an unidentified species of hermit, living in the empty shell of the murex Chicoreus
aculeatus. A hermit crab has a soft abdomen, which it tries to protect by taking up residence in
empty mollusk shells.
Keiji’s hermit crab
Pylopaguropsis keijii
This small, fast-moving crab is occupying the shell of Colubraria nitidula.
Hermit crab in frog shell
Pylopaguropsis sp.?
This hermit is living in the empty shell of the frog shell, Bursa granularis.
Blue-kneepad hermit crab in cowry
Dardanus guttatus
One of the larger hermit crabs, this one has a flattened body and prefers to occupy shells with
narrow apertures, such as cowries and cones. This one is in the shell of the large tortoise cowry
(Chelycypraea testudinaria).
Blue-kneepad hermit crab in cowry
Dardanus guttatus
Closer shot of the previous scene. The crab is easy to recognize with its dark maroon legs
bearing bright white spots and blue to turquoise “kneepads.”
Blue-kneepad hermit crab in cowry
Dardanus guttatus
Same as previous scene with the crab righting the shell and grazing on the algae-covered rock.
His large claws grasp small bits of food and bring them up within reach of its mouthparts,
specialized appendages adapted to take the food from the claw and deliver it to the crab's mouth.
Green damsels over algae
Chromis viridis
The green Chromis damsels are clustering over a clump of Tydemania algae, possibly getting
ready to spawn. The greenlined trigger (Balistapus undulatus) comes in from the left and pushes
them away.
Male ember parrotfish
Scarus rubroviolaceus
One of the larger parrots commonly seen at Kwaj. This one is a green male. The female is more
of a bicolored reddish brown (next scene). Parrots, like a number of other fish, can change sex as
they grow and each phase often has one or more different color phases. The basic pattern is to
start out as unsexed juveniles, change color as they develop into mature females, and later in life,
change color again as they turn into males. But in fact, it is actually somewhat more complicated
than this. Often the initial adult phase parrots can be either male or female and look essentially
the same. As they grow, both initial females and early males may change to later-stage males and
develop a terminal phase color form.
Female ember parrotfish school
Scarus rubroviolaceus
A large school of mostly females (and maybe initial phase males) swims by. Many parrots
typically occur in schools.
Pacific steephead parrotfish
Chlorurus microrhinos
This scene shows a large, older male with a well developed rounded bump on its forehead.
Parrots have several rows of teeth fused together into a parrot-like beak, which they use to graze
the algae growing on dead coral reef rock. In the process, they scrape away some of the rock as
well and are important bioeroders of the reef. The reef scrapings they ingest with their algae are
processed through the digestive system and released as fine sediment.
Male bicolor parrotfish
Cetoscarus bicolor
This distinctly colored species goes through very different color forms as juvenile and initial
adult male or female. This one is a terminal phase male and is having its parasites picked by a
cleaner fish, Labroides dimidiatus.
Pacific longnose parrotfish
Hipposcarus longiceps
This mostly white species is seen sporadically on both lagoon and seaward reefs.
Red parrotfish
Scarus xanthopleura
This is the initial adult color phase of this species. The bright red is striking for a parrotfish. The
terminal phase male is green.
Female bridled parrotfish
Scarus frenatus
Initial phase coloration. A damsel chases this grazing parrot away from its algae-covered rocks.
A number of different damsels and other fish vigorously defend specific areas against roaming
grazers like parrots and tangs.
Male bridled parrotfish
Scarus frenatus
This is the terminal phase male of this species. The female is in the previous scene.
Male filament fin parrotfish
Scarus altipinnus
This school of mostly terminal phase males is streaming into a surge channel. Actually, the
school also contained many initial phase individuals of this species in a dark brown color. (Next
scene.)
Female filament fin parrotfish
Scarus altipinnus
This is the latter portion of the school that was mostly males in the previous scene.
Undulated moray at night
Gymnothorax undulatus
This is a somewhat aggressive moray eel. It usually stays hidden in rocks by day and emerges at
night to hunt fish.
Whitemouth moray
Gymnothorax meleagris
This eel is easily recognized by the white spots on its dark brown body and the bright white
inside the mouth. It can often be seen poking its head out of a hole in the reef during the day.
Giant moray
Gymnothorax javanicus
This is the largest species of moray. It is often seen with its head out of a hole by day and may
completely emerge at night to feed. Although certainly capable of inflicting a very nasty and
dangerous bite, this species tends to be less aggressive than some of the smaller species.
Giant moray
Closer view of the head. It opens and closes its mouth as it breathes.
Gymnothorax javanicus
Bornella nudibranch
Bornella johnsonorum
This uncommon species is usually seen at night in seaward reef channel and lagoon pinnacle
ledges and caves. Typical size is about 25 to 30mm (an inch or a little over). Named from
specimens found at Kwajalein and Enewetak Atolls, so far this species is known only from the
Marshall Islands.
Eel-like Bornella nudibranch
Bornella anguilla
This unusual creature swims like a small eel when disturbed. It lives in seaward reef channel
ledges and comes out only at night. This species was originally described and named from
Kwajalein but is now known throughout much of the tropical Indian and western Pacific Oceans.
Kwajalein's Trapania nudibranch
Trapania circinata
A pair of black tentacles and pair of larger black rhinophores are at the right side of the photo,
and the grayish gills are in the middle of body. You can see the internal reproductive organs
through the semi-translucent white skin between the rhinophores and gills. So far this recently
named species is known only from Kwajalein Atoll. They are small, this one only about 17mm
long.
Picta nudibranch
Phyllidia picta
This one resembles several other species that are all poisonous and form a Mullerian mimicry
group. Mullerian mimicry occurs when a bunch of uncommon, usually poisonous species evolve
to resemble one another. Suppose a predatory fish might be willing to try to eat a poisonous or
distasteful species. At first bite, it might realize that the prey is inedible and spit it out. If that
prey had a memorable color pattern, the predator might remember and avoid those in the future.
However, that one bite might have injured or killed the poisonous prey. If a bunch of different
poisonous prey species looked different, the predator might have to test each kind, possibly
damaging or killing one of each. Spread that over a bunch of predators, and even though the prey
cannot be eaten, they might lose a lot of members. However, if a number of different poisonous
species all look similar, it may be that a predator learning a lesson from one will keep it from
trying the others. In this way, the mimics all help protect each other. The process of natural
selection would favor those who look alike, causing the different species to slowly evolve
towards a mutual resemblance.
Desirable nudibranch
Flabellina exoptata
This small nudibranch species is often up in the shallows where it has to hang on tight in the
surge. It eats hydroids. This one measures about 20mm.
Tiger cowry
Cypraea tigris
The tiger cowry is easily recognized. One of the largest cowries here at Kwaj, it is also one of the
few that is often seen out in the open during the day. Here we see the anterior end first, then
zoom out to show the entire shell. The mantle, the thin layer of tissue that creates the cowry shell
and completely covers it at night, is here shown partly extended with a bit of the spotted shell
still visible at the top. Most cowry mantles have soft spiky or branching projections called
papillae that may function to increase the surface area of the mantle or break up the shell's
rounded outline for camouflage. The largest tigers from Kwajalein reach just over 100mm (about
4 inches).
Tapering cowry
Talostolida teres
This species has a red mantle, seen here extending a bit out over the base of the shell. This
species usually lives under rocks on a variety of lagoon and seaward reefs.
Tapering cowry on eggs
Talostolida teres
This individual is on its mass of brown egg capsules and has its red mantle fully extended. A tiny
hermit crab in the seashell Caducifer truncata crawls across. Cowries brood their eggs, usually
covering them with the cowry's foot to protect them from egg eaters while they develop. This
keeps the mother cowry in one place for several days without eating while the eggs develop and
hatch. Most, maybe all, Kwaj cowry eggs develop into free floating larvae called veligers that
drift around in the plankton for a while growing larger until they finally settle down to a reef and
begin a benthic existence.
Maria’s cowry
Annepona mariae
This small round cowry is found primarily in seaward reef surge channels. It is nocturnal and
hides well, so usually only empty shells are seen during the day. This one measures about 15mm
long.
Windowpane murex
Marchia martinetana
This is a rare murex shell from lagoon pinnacle and seaward reef habitats. The shell is covered
with delicate fluted sculpturing, but the white-circle color pattern on the living animal is equally
striking.
Windowpane murex
Marchia martinetana
Here is the same animal as previous scene. It was taking too long to pull itself forward, so the
scene was split.
Cuming’s murex
Naquetia cumingi
Many murex shells get their shells encrusted with coralline algae and other growth, making them
difficult to recognize.
Cuming’s murex
Naquetia cumingi
The animal is trying to pull its aperture down to the bottom but something is preventing it.
Wentletrap on fungiid coral
Epitonium sp.
This species is always found living underneath its prey, an elongate fungiid coral named
Herpolitha limax. Thin delicate shells, there are a number of different kinds of wentletraps at
Kwaj, mostly small. One of the larger species from the western Pacific was expensive and highly
prized among European collectors in the 18th century. It is said that clever Chinese artisans made
extremely accurate rice paste forgeries of the shell for sale to unsuspecting travelers and
explorers. The deceit worked well until the buyer dipped the shell in water to clean off
accumulating dust and the shell dissolved! It is not known how widespread this practice was, but
according to S. Peter Dance in Rare Shells, at least one forgery still exists; it is far more valuable
now as a work of art than the real shell ever was. Dance says that the fake shell "would deceive
an expert, for apart from its lighter weight and duller surface texture, there is nothing to suggest
forgery."
Wentletraps
Where you see one, there will often be more.
Epitonium sp.
Tesselate cone
Conus tessulatus
This cone lives buried in sand by day in a variety of lagoon and seaward reef habitats.
Red cone
Conus pertusus
This is a small cone, usually seen nocturnally in seaward reef ledges and caves. One 25mm long
would be quite large.
Floccatus cone
Conus floccatus
This fish-eating cone shell is rarely seen alive, but old empty shells are not uncommon. It lives in
a variety of lagoon and seaward reef habitats. Cones use a tooth modified into a venomous
harpoon to stun or kill prey. As a fish eater, the sting from this cone is potentially dangerous to
humans. If you have to handle it, do so carefully!
Maxima clam
Tridacna maxima
Tridacna maxima is the smallest and most numerous of the giant clam family in the Marshalls.
The shell is usually embedded in reef rock, which it bores into a bit by moving its hard shell back
and forth. The species comes in a variety of colors but is easily distinguished from the other two
Marshall Islands members of the same family by the presence of a row of close-set black spots
near the outer edge of the mantle. This individual is mostly blue and brown.
Maxima clam
Blue green with black stippling.
Tridacna maxima
Maxima clam
Darker purple blue spotted with black.
Tridacna maxima
Maxima clam
Tridacna maxima
Brown with a blue interior. Most of the colors in these animals come from single-celled plants
called zooxanthellae that live symbiotically within the clams’ tissue. The plants use the carbon
dioxide produced by the animal for photosynthesis and return to the clam oxygen and carbon
compounds for food. These zooxanthellae form similar symbiotic relationships with reef building
corals and anemones, and with some nudibranchs. Even though the colors vary considerably
from clam to clam, it is certain they are derived from the symbiotic plants. Plants require
sunlight, and occasionally you can find a clam that has been deprived of sunlight for some time,
if, for example, a table coral breaks off and permanently shades it or part of it. In those cases, the
clam or the part of the clam that is shaded loses all its color as the plants die off.
Maxima clam
Light and dark brown.
Tridacna maxima
Maxima clam
Interesting combination of green, brown, and blue.
Tridacna maxima
Maxima clam
Dark green with some black.
Tridacna maxima
Maxima clam
Green, light brown and black. Embedded in living Porites rus coral.
Tridacna maxima
Maxima clam
Tridacna maxima
Purple, brown and black. Purple is an unusual color in these clams. It seems that no two
individuals are exactly alike in color.
Maxima clam
Tridacna maxima
This blue and black one is embedded in living coral. A juvenile of the wrasse Thalassoma
lutescens passes by.
Yellow slingjaw wrasse
Epibulus insidiator
This common wrasse comes in several different color forms, including yellow, black and a
combination of black, red and white.
Slingjaw wrasse slinging jaw
Epibulus insidiator
Here is the more common color form of the wrasse in the previous scene. It is called a slingjaw
wrasse because it is able to stretch out its mouth for capturing prey.
Blue-spotted wrasse
Anampses caeruleopunctatus
This wrasse is rare in the Marshalls and is usually on seaward reefs. The common name is
derived from the scientific name "caeruleopunctatus" although there seem to be no blue spots on
the adult.
Thicklip wrasse
Hemigymnus melapterus
This wrasse picks up mouthfuls of sand or debris, chews it around a bit to separate out any food,
and spits the remainder.
Yellowtail wrasse
This fast moving wrasse is usually hard to get very close to.
Juvenile dragon wrasse
Anampses meleagrides
Novaculichthys taeniourus
This is a juvenile specimen. It is called the rockmover wrasse in some books because of its habit
of picking up rocks with its mouth and dropping them while searching for hidden prey. Young
ones like this drift about as though they are pieces of detritus washed around by currents and
surges.
Lyretail grouper
Variola lauti
This colorful grouper tends to be a bit shy of divers, although sometimes one may be curious and
follow a diver around. They are not uncommon on lagoon and seaward reefs.
Arc-eye hawkfish
Paracirrhites arcatus
These small hawkfish spend most of their time perched on coral waiting for small prey to come
by.
Blackside hawkfish
Paracirrhites forsteri
This is most likely one of the color forms of Paracirrhites forsteri, or it is possibly a species
named P. typee.
Spotted sweetlips
Plectorhinchus picus
These nocturnal sweetlips are most often seen hanging out under or near large table corals during
the day.
Spotted sweetlips
Plectorhinchus picus
This individual was out on top of its table coral hangout while being picked over by a cleaner
wrasse.
Squaretail coralgrouper at night
Plectropomus areolatus
This grouper is very shy and hard to approach during the day. This scene was shot at night.
Blacksaddle coralgrouper at night
Plectropomus laevis
This is also sometimes called the giant coralgrouper. Usually more brown with blue spots, this
one is unusually reddish, probably because it was filmed at night. These large groupers are likely
to cause ciguatera poisoning when eaten. If you watch this one closely, a small cleaner shrimp
passes over the head picking parasites.
Blacksaddle coralgrouper at night
Plectropomus laevis
Closer shot of the head of a sleeping individual. What nice teeth you have.
Blacksaddle coralgrouper yellow form
Plectropomus laevis
This is a less common color form of this grouper. A large cleaner wrasse (Labroides bicolor) is
looking over the grouper for parasites but swims off at the end.
Blacksaddle coralgrouper being cleaned
Plectropomus laevis
This is the more common color form during the day. This one is being cleaned by a pair of
cleaner wrasses (Labroides dimidiatus), which are even swimming fully inside its mouth to pick
at parasites inside the mouth and on its gills. These groupers are voracious predators on small
fish, yet they permit the cleaners these liberties without eating them. It shows that the cleaning
process must enhance the survival of the fish that allow themselves to be cleaned.
Blacksaddle coralgrouper and blue fusiliers
Plectropomus laevis / Caesio teres
The grouper swims off as some blue and yellow fusiliers come in.
Blue and yellow fusiliers
Caesio teres
These fish often form large schools that may swarm around a diver. They are common on the
seaward reef and some lagoon pinnacles.
Blue and yellow fusiliers
Looking up toward the surface to see the fish pass above.
Caesio teres
Neon fusiliers
Pterocaesio tile
Like Caesio teres, these often form large schools and sometimes swarm around divers. These are
also called bluestreak fusiliers.
Neon fusiliers
These couldn’t decide which way to go.
Pterocaesio tile
Green sea turtle through fusiliers
Chelonia mydas
In the distance, the turtle swims slowly past a school of neon fusiliers (Pterocaesio tile).
Hawksbill turtle
Eretmochelys imbricata
From a distance this one looks like a hawksbill. It swims slowly along a seaward reef surge
channel.
Hawksbill turtle
Eretmochelys imbricata
The turtle swims past on the dropoff. Sometimes these turtles are not afraid of divers, although
they are still captured and eaten by some Marshallese.
Hawksbill turtle eating sponge
Eretmochelys imbricata
This one looks as though it is having a bit of trouble swallowing a chunk of sponge it ripped off
the bottom. Hawksbills typically eat benthic invertebrates, while the other common sea turtle
here, the green turtle (Chelonia mydas) is mostly an algae eater as an adult. Both kinds will go
for jellyfish.
Grouper through cave
A silhouetted grouper is visible through a small tunnel on the seaward reef.
Acropora coral
Common in shallow on seaward reefs.
Acropora danai?
Soft coral
Sarcophyton
A cluster of Sarcophyton colonies grows on the hard coral Porites. The soft coral polyps are
extended on the clumps along the left and retracted on the ones on the right.
Fire coral paddle form
Millepora
This is one of the growth forms of the common fire coral. Fire corals have strong stinging cells
known as nematocysts that cause a painful burning sensation on bare skin. Most corals and their
relatives possess nematocysts, but in many species the stingers are too small or the venom too
mild to have any effect on humans.
Pink coral in cave
Stylaster
Although related to the fire corals, the pink Stylaster does not sting. It usually lives in ledges and
caves, where it often hangs down from the ceiling.
Red coral at Namu
Distichopora violacea
This particular color form does not seem to exist at Kwajalein Atoll, but is common in parts of
Namu Atoll, just 56km (about 35 miles) south of Kwaj.
Coral polyps closeup
Montipora
Closeup of lavender polyps. An individual coral polyp is kind of like a tiny sea anemone that
builds a calcium carbonate skeleton.
Coral wavy growth form
Looks like a rugged mountain range shot from above.
Pachyseris rugosa
Green tube coral
Tubastraea micrantha
This is the only colony of this coral species we know of at Kwajalein. It is an abundant coral in
the passes at Pohnpei and farther west. Unfortunately, this colony is in what is now a restricted
area off the west end of Kwajalein.
Trumpet fish by orange fan coral
Aulostomus chinensis
Trumpet fish often hide in or around gorgonians. This one is in front of an orange fan coral
(Anella mollis).
Twospot lizardfish
Synodus binotatus
This species is named for the two spots barely visible in the video near the tip of the snout. It was
originally named from Kwajalein back in 1953.
Lizardfish pair on coral
Synodus variegatus?
Two individuals swim away. Lizardfish are typically predators upon other fish. They lie
motionless until they see their chance, then dart out and grab small unsuspecting fish.
Unfortunately, divers blundering by often distract the prey causing them to fall easy victim to
lizardfish. Several times I’ve seen lizards grab small fish who were probably too busy watching
me to pay attention to their surroundings.
Ghost pipefish
Solenostomus cyanopterus
These small ghost pipes often hang around algae or rubble and are difficult to recognize as fish.
With their small mouths, they feed on tiny live shrimp. Although extremely cute and fascinating,
they do not do well in aquariums and should be left on the reef.
Sharksucker
Echeneis naucrates
These are usually found hitching a ride on sharks or other large marine animals such as turtles or
rays. They have an oval sucking disk dorsally on the head that attaches to the host. Occasionally
you see them swimming freely, and they often take a keen interest in divers, perhaps looking for
another host to which to attach. When I see one by itself, I can't help looking around to see if the
big shark it came from is nearby. But if the shark was there, the sharksucker probably wouldn't
be interested in me. Although their teeth are small, they have been known to bite divers. I have
been bitten on the leg (just scratched the skin) and once had one grab my hair on the front of my
head and pull it several times before letting go.
Sharksucker school
Echeneis naucrates
This was a rarely seen cluster of sharksuckers, possibly congregating for mating. A couple of
them at least do seem to be courting.
Whitetip shark
Triaenodon obesus
Most whitetips are quite slender sharks, so the specific name obesus (which means what it looks
like) is not very appropriate. Perhaps it was named from a female about to give birth. These are
common throughout the atoll and are nearly always less than about 5 feet or about 1.75 meters
long. They tend to be mild-mannered, but are sometimes curious and may swim right up to
divers to get a close look. Although rarely dangerous, they could bite in the presence of speared
fish. They can often be seen resting on the bottom, usually in small caves or ledges. Sometimes
several young ones will gather underneath a large spreading table coral.
Gray reef shark
Carcharhinus amblyrhynchos
This is another very common shark in the atoll, although we see far fewer in the southern part of
the atoll than we did in the ‘60s and ‘70s. It would seem that 50 years of high diving activity or
lots of boat traffic has either pushed the sharks away from the designated boating area around
Kwajalein or desensitized them to divers’ presence so they no longer come around to investigate.
Outside the boating areas, gray reefs are still common and curious. The dorsal and pectoral fins
of gray reefs are mostly unmarked, but the species can easily be recognized by the black trailing
edge to its tail fin. The vast majority of gray reefs pose no problem to divers, but they must be
considered potentially dangerous, especially in the presence of spearfishing but sometimes
simply because they apparently feel their territory has been encroached upon. Territorially
aggressive gray reefs swim in a peculiar manner called posturing, with their back arched and
nose bent up, pectoral fins pointing more down than to the side, and moving from side to side in
an exaggerated S shape. A posturing gray reef could break posture and attack at the slightest
provocation: swimming at the shark, taking a flash photograph, or banging on one’s tank are all
actions that have triggered attacks in other places. Divers should always be cautious around gray
reefs. But learn to recognize a posturing gray. The shark will never initiate a territorial attack
without first posturing, and you can always prevent an attack by not doing anything a posturing
gray considers threatening.
Gray reef shark
Carcharhinus amblyrhynchos
This was one gray reef that worried me, even though it was not swimming in its aggressive
posture. Although a good 5 feet (1.75m) in length, the shark was skinny, and its skin was marked
and discolored. It looked as though it had been sick for some time, and I was slightly concerned
that it might be ill and hungry enough to try eating anything, including a slow-moving diver.
Fortunately, after several close passes, the shark moved away.
Silvertip shark
Carcharhinus albimarginatus
The silvertip is a large shark, usually seen rather deep on the seaward reef dropoff. One of the
best places to see them seems to be on the windward seaward reef, such the ocean side of Bigej.
Although I have not personally witnessed any aggression from silvertips, they have been known
to attack divers in the presence of spearfishing. They also have been known to eat gray reef
sharks, and anything that can do that deserves respect. While I have seen them here at Kwaj only
on the seaward reef, they may come into the lagoon to pup. At Rongelap Atoll in 1982 I saw a
number of small ones, less than a meter long, in the deep lagoon while we were collecting
sediment cores. It seems that pounding the plastic coring tubes into the sand produced an
effective shark call.
Silvertip sharks
Carcharhinus albimarginatus
Two silvertips cross paths. These are some distance away, but large, in the 7 to 8 foot range
(about 2.1 to 2.5m).
Lagoon Pinnacles
Abundant coral cover
Some of the lagoon pinnacles have extremely heavy and diverse coral growth, which in turn
attracts multitudes of different fish. The midlagoon pinnacles can be some of the most interesting
places to dive, although care must be taken on windy days. If your boat anchor slips on a windy
day, it could be a very long swim to safety. Also, it has been my experience that the gray reef
sharks seem to be a bit more territorially aggressive on pinnacles than they are on the seaward
reef. This pinnacle is a rather small one near the island of Eniwetak, near Meck.
Swim over dense corals
This footage was taken swimming over the slope of a pinnacle variously called “Q buoy” or
Twin Peaks. This reef obviously has a good crop of Acropora, Porites, Lobophyllia, and fungiid
corals and more. Living coral seems to cover every square centimeter of this slope. This pinnacle
is also a great place to see several nice magnificent anemones, Heteractis magnifica.
Corals & algae
This swim-over shows a bluish species of Acropora coral interspersed with other corals and
clumps of green Halimeda algae. This is on the shallow reeftop of a large pinnacle north of
Eniwetak Island.
Neon fusiliers over elkhorn
Pterocaesio tile
A small school of fusiliers passes over a dense stand of elkhorn and staghorn Acropora corals on
the slope of a large lagoon pinnacle. The elkhorn (Acropora rotumana), with the wider branches,
was recently reported by a scientific team on an expedition to Arno Atoll. They were excited
because this coral had not been scientifically reported in over 100 years, and the newspapers
touted the find as the "world's rarest coral." Not quite. The coral is abundant on a variety of reefs
at Kwajalein Atoll and is probably as abundant throughout the southern Marshall Islands at least.
I'm certain there are corals much rarer than this one.
Ball coral
Platygyra?
This coral forms massive rounded coralheads in shallow water. Here is shares a reef with
Acropora in front of it and a few tangs and parrotfish behind.
Coral wars
Plate-like Montipora coral is growing up and around the tall spikes of Acropora. There is a
constant slow-motion battle on the reef for space and access to sunlight, which is required for
coral survival. One strategy is to grow right over other corals. Another is to grow up and spread
out, shading those beneath, as done by table corals. A number of green-banded staghorn damsels
(Amblyglyphidodon curacao) and several brushtail tangs (Zebrasoma scopas) are also present.
Stalk coral
Lobophyllia hemprichii
Like most other corals, these stalk colonies start with a single settled coral larva that divides as it
grows to form a multi-polyp colony. In this case, each coral individual grows out in straight
stalks, and as it repeatedly divides and grows it forms these dome-like mounds. The separate
stalks are not solidly attached together, so often, particularly in those growing on a slope, you see
colonies broken up into separate stalks, often still living at the tips. This coral comes in several
color forms based on the strain of symbiotic zooxanthellae algae living within the coral tissue.
Stalk coral is abundant on pinnacles in quiet waters very close to Kwajalein in the southern part
of the lagoon, such as those near G, K10, K9, and K7 buoys. It is less common on midlagoon
pinnacles or those near reef passes where there is more water movement.
Stalk coral
This may be another species of stalk coral.
Lobophyllia sp.
Fluorescent coral
Symphyllia sp.
This scene of a species of Symphyllia coral was shot at a depth of about 30 meters (about 100
feet) with available light. Red and orange colors from sunlight, however, are quickly absorbed
when passing through even the clear waters at Kwajalein. Straight sunlight reflected from this
coral at this depth would not have any red color left to see. What is apparently happening here is
that proteins in the coral are converting the high energy wavelengths of light in the green, blue
and violet wavelengths, reflecting or retransmitting it as lower wavelengths such as orange and
red. Why it would do this is unknown, but one theory suggests that this could aid in
photosynthesis of the symbiotic zooxanthellae, the unicellular plants hosted within coral tissue
that provide the coral with much of its oxygen and food.
Fungiid coral
Halomitra pileus
This coral is common on lagoon pinnacles and often forms upside-down bowl shaped colonies
that are hollow underneath. This particular colony is unusually tall and narrow. A more typical
spreading bowl shaped one can be seen about eight scenes back (Swim over dense corals) on
Twin Peaks.
Yellow green Turbinaria coral
Turbinaria sp.
This coral can form large colonies, sometimes several meters across, on lagoon pinnacles and the
seaward reef.
Pink & yellow coral in cave
Stylaster / Distichopora spp.
Here is a growth of pink Stylaster and yellow Distichopora corals in a small cave on a lagoon
pinnacle about halfway up the atoll. For some reason, this yellow Distichopora is not present at
all in the southern portion of the lagoon, even on isolated reefs where divers never go. It starts to
show up on pinnacles and the seaward reef around Legan Island and gets more common to the
north.
Yellow coral
Distichopora sp.
A colony of yellow Distichopora coral with some sponge and colonial tunicates grows in the
shade of a table coral on a small lagoon pinnacle near Eller Island.
Yellow coral
A closer view of the same spot.
Distichopora sp.
Purple coral
Distichopora sp.
This purple coral is related to and might even be the same species as the yellow Distichopora
shown in the previous scenes. The purple species is found throughout the atoll, and is sometimes
intermixed with the yellow on northern reefs. At times there is also a muddy brown variety that
almost looks as though it could be a combination of the purple and yellow forms. These are also
related to the red Distichopora seen earlier from Namu Atoll.
Hot pink nudibranch on bryozoan
Aegires nakamotoensis
Looking a little bit like a coral is the branching bryozoan in this scene. These are found in the
shade under ledges on lagoon pinnacles and sometimes on seaward reefs. Often it is being eaten
by the tiny hot pink nudibranch, seen here in the middle of the frame. The nudibranch is less than
10mm long.
Green spotted nudibranch
Nembrotha cristata
This green spotted nudibranch is related on one seen earlier in the video, Nembrotha kubaryana,
which has brilliant red color on its foot margin, rhinophores, and gills. Nembrotha cristata is
always black with green spots that are more elevated than those of N. kubaryana. This species is
seen occasionally on various lagoon and seaward reefs, where it feeds on the green tunicate seen
in this scene. The tunicate prey appears to come and go, and the nudibranch predators do the
same. In September of 1998 and August of 2000, a small pinnacle near Onemak Island had an
abundant growth of the tunicate, and we saw many of the nudibranchs scattered about eating
their fill. A few years later, none were to be found. In August of 2008, the top of the pinnacle
near Y buoy had a similar abundant growth of the tunicate, and both of these green-spotted
Nembrotha species were common. Now most of the tunicate is gone, and the nudibranchs are
scarce.
Pinnacle nudibranch
Ceratosoma palliolatum
This Ceratosoma palliolatum is found almost exclusively on lagoon pinnacles, where it is
occasionally seen in ledges and small caves at night.
Elisabeth’s nudibranch
Chromodoris elisabethina
One of the more common chromodorid nudibranchs at Kwajalein is Chromodoris elisabethina. It
can be found on a variety of lagoon and seaward reefs, but seems most common in shaded ledges
and on the slopes of some large midlagoon pinnacles. Many nudibranchs are toxic or highly
distasteful to predators, and appear to develop bright colors and patterns to warn away potential
predators.
Pink sponge nudibranch
Verconia sp.?
A reasonably common but rarely observed nudibranch is this small undescribed species of
chromodorid. It is always found on clumps of pink sponge that typically grow on deeper lagoon
reefs and sand patches. They have also been seen on shipwrecks, where this sponge is common.
It camouflages itself so well on its prey sponge that it is likely that this is one nudibranch that is
not toxic and may be eaten by some predators. If so, being hard to find would be an advantage.
The nudibranch is in the center of the scene, directly between two holes in the sponge colony.
Sap sucking seaslug
Elysia sp.
This animal is an undescribed species of Elysia, a group related to but not actually included in
the nudibranchs. Nudibranchs are all carnivores, eating animals such as sponges, corals,
bryozoans, and so on. All sacoglossans, the group that includes Elysia, are herbivores. Many of
them have a fine pointed tooth they use to puncture individual plant cells, from which they suck
out the juices. Since these are often seen out crawling about during the day, it is likely they have
a chemical defense (toxins) that keep predators away.
Marten’s pleurobranch
Berthella martensii
Another group related to nudibranchs includes the pleurobranchs. Many pleurobranchs have
small internal shells not present in nudibranchs. These typically live in the dark under rocks on
various lagoon and seaward reefs, and mostly appear to eat sponges. This one is one of numerous
color forms of the species Berthella martensii.
Caledonian pleurobranch
Berthella caledonicus
Another pleurobranch with a brown spot in the middle of its back sits next to its white spiraled
egg mass.
Grouper & balled-up anemone
Epinephelus polyphekadion / Heteractis magnifica
As the camera approaches a pink-based, balled-up magnificent anemone (Heteractis magnifica),
it is at first easy to miss the camouflaged grouper (Epinephelus polyphekadion) on the rock to the
left. There are several apricot clownfish (Amphiprion perideraion) in the anemone and the
grouper may be waiting for his chance to grab one if it moves far enough from the stinging
tentacles of the anemone. But the diver’s approach causes the grouper to retreat.
Apricot clownfish in magnificent anemone Amphiprion perideraion / Heteractis magnifica
The anemone Heteractis magnifica is most common on lagoon reefs and pinnacles, and nearly
always is occupied only by the apricot clownfish (Amphiprion perideraion) and possibly a few
black and white threespot damselfish (Dascyllus trimaculatus). Heteractis magnifica is probably
the most massive of the anemones here, although the carpet anemone, Stichodactyla mertensii,
probably comes close. Heteractis magnifica comes in several colors, both of the tentacles and of
the stalk, which is blue on the individual at the beginning of this scene. These anemones
occasionally “ball up” and then spread out again for no obvious reason, although perhaps they
ball up occasionally to take in and digest any plankton that have stuck to the tentacles. This
species is also highly susceptible to coral bleaching, and at those times the tentacles turn white or
bright yellow, sometimes with blue or green tips. Bleaching occurs when the symbiotic
zooxanthellae plants within the sea anemone (like in reef corals) are expelled, which is thought
to happen when the water gets too warm. We have seen several instances of bleaching of these
anemones, but fortunately they have always survived and come back. This scene was shot on B
buoy pinnacle, where there are about nine of these anemones in a line along one side of the
pinnacle’s top. It is a tough place to anchor, though—a small head with a lot of live coral on top.
Definitely not a place to go if there is any wind!
Apricot clownfish in magnificent anemones Amphiprion perideraion / Heteractis magnifica
This is a Heteractis magnifica anemone with a white stalk. Actually, there are three anemones
here clustered together, two of them behind the one that is partly balled up. The numerous
apricot clownfish (Amphiprion perideraion) move freely among the three anemones.
Apricot clownfish in magnificent anemone Amphiprion perideraion / Heteractis magnifica
Here is a large spreading yellow Heteractis magnifica with several Amphiprion perideraion on a
pinnacle near Kwajalein.
Apricot clownfish in magnificent anemone Amphiprion perideraion / Heteractis magnifica
This is a balled-up and bleached Heteractis magnifica with a bright pink stalk.
Apricot clownfish in magnificent anemone Amphiprion perideraion / Heteractis magnifica
A closer view of a pair of Amphiprion perideraion darting among the tentacles of a Heteractis
magnifica.
Apricot clownfish in magnificent anemone Amphiprion perideraion / Heteractis magnifica
This Heteractis magnifica has a blue stalk and blue tips to its tentacles.
Tomato clownfish in carpet anemone
Amphiprion melanopus / Stichodactyla mertensii
Most often, the tomato clownfish, Amphiprion melanopus, prefers to live in a different kind of
anemone, the brown Entacmaea quadricolor. This one on Twin Peaks, however, has taken up
residence in a carpet anemone, Stichodactyla mertensii, which is usually occupied by two- or
threestripe clowns (Amphiprion chrysopterus or A. tricinctus). We first saw a tomato clown in
this particular anemone in 1993, and since we have never seen another fish of this species in any
carpet anemone, we feel sure it is the same one, which now must be at least 18 years old.
Crambione jellyfish
Crambione mastigophora
The tentacles of this jelly pack a pretty powerful sting. Another can be seen in the distance
behind the close one. These sometimes aggregate in large numbers, and a group of jellyfish is
called a “smack.”
Crambione jellyfish
Crambione mastigophora
You can catch a couple of glimpses of a small fish that has chosen to hide around this jellyfish. It
should be safe from predators, but had better watch out for the stinging tentacles.
Crown jellyfish
Cephea cephea
This jellyfish gets its common name from the rounded ball of jellied spines on top of the bell
(facing down in this photo).
Big crown jellyfish
Cephea sp.?
This jelly has a low dome of small bumps on top of its bell and seems to lack elongate tentacles
underneath. It is the largest jelly we have seen in these waters.
Moon jellyfish
Aurelia aurita
These mostly transparent jellyfish seem to hang around mostly near the surface. Their tentacles
do not appear to sting divers.
Clear jellyfish
Aequorea australis
This jelly is mostly transparent and has long tentacles that stream behind the bell. The tentacles
do not have a potent sting. These jellies seem to be seen most often by divers doing their safety
stops after dives on lagoon shipwrecks.
Bumpy jellyfish
This small pinkish jellyfish is mostly rare here.
Timoides agassizi?
Tiny box jellyfish
The box jellies, or cubomedusae, are often capable of producing extremely painful and in some
cases life-endangering stings. This species is very small, maybe 10 to 15mm (half an inch) in
diameter, and seems to spend time in clumps of algae on the bottom. Having wisely decided not
to test it, we do not know if this is a species with a potent sting.
Foxface rabbitfish juveniles
Siganus vulpinus
Adults of this species are most common on lagoon pinnacles with heavy coral growth, although
they may also be seen on lagoon reefs and very rarely on the seaward reef. Juveniles, like these
two, can be found down in the coral and algae on quiet lagoon pinnacles and reefs. This pair
happened to be hiding among the Halimeda algae growing on a shallow lagoon shipwreck at
North Loi Island.
Foxface rabbitfish being cleaned
Siganus vulpinus
Here are a couple of adults lining up to have their parasites picked at a cleaning station above
some staghorn Acropora coral on a lagoon pinnacle. Although they are often found in high coral
areas, they appear to eat algae from the bottom.
Rabbitfish, several species
This scene shows three of the four kinds of rabbitfish found at Kwajalein. The several yellow
ones with the longitudinal wavy bluish gray lines are bluelined rabbitfish (Siganus puellus). The
grayish fish covered with round reddish spots is the goldspotted rabbitfish (Siganus punctatus).
And near the end, a foxface rabbit (Siganus vulpinus) comes into the scene. Damsels and tangs
round out this cluster of fish on the lagoon pinnacle off North Loi Island.
Bluelined rabbitfish
Siganus puellus
Four individuals of Siganus puellus travel in formation. These are sometimes also called the
masked rabbitfish.
Elongate surgeonfish school
Acanthurus mata
A school swims slowly by on a lagoon pinnacle. These fish can rapidly change from black to
pale blue and back.
Blackeyed unicornfish
Naso thynnoides
These are also known as the slenderspine unicornfish. These form schools around some lagoon
pinnacles.
Lined unicornfish
Naso brevirostris
Here is another common name that is hard to understand unless you see these close up in their
lighter phase, where they can show thin vertical lines on the body. It seems that spottail would be
more appropriate. The scientific name “brevirostris” roughly means short snout, and I presume
refers to the unicorn spine on the forehead. In fact, this spine is longer than it is in many species
of Naso (unicornfish) so the shortsnout unicornfish would not be too appropriate either. These
usually form schools on lagoon and seaward reefs, and they can change color quickly when
displaying.
Sailfin tang
Zebrasoma veliferum
These are found on a variety of lagoon and seaward reefs but seem most common on lagoon
pinnacles. Usually paired on single, sometimes they form small schools. Young ones often have
yellow replacing the white and their dark bands are narrower. A colorful regal angelfish
(Pygoplites diacanthus) is also present in the clip.
Yellow tang
Zebrasoma flavescens
At Kwaj this is a rare counterpart to the mostly black brushtail tang (Zebrasoma scopas). The
two fish are shaped exactly alike, differing only in color. In Hawaii, only the yellow Z.
flavescens is present. Here at Kwaj, Z. flavescens is very rare but Z. scopas is abundant. At
nearby Enewetak Atoll, there were good numbers of both species. The two species are apparently
very closely related and able to hybridize, producing progeny that are more dirty yellow than
bright yellow. Here at Kwaj, because the yellow ones are so rare and must have a hard time
finding a mate of the same species, we see more hybrids than true bloods. In fact, the individual
in this scene is not as bright yellow as the species usually is, so it is likely a “mostly yellow”
hybrid.
Achilles tang
Acanthurus achilles
This is another tang that is rare here, where its place is taken over by the abundant goldrim
surgeonfish (Acanthurus nigricans). In Hawaii their positions are reversed—A. achilles is
common and A. nigricans rare. We have seen these only a few times here at Kwaj. The animal
figured lived on a lagoon pinnacle, Shark City coralhead, for some years before it disappeared.
One more specimen was observed on the seaward reef north of Ennubuj (Carlson). A small
group was found back in 1975 on a shallow reef by the edge of the pass south of Omelek Island,
but it was hard to concentrate on them while being buzzed by curious gray reef sharks. The most
we have seen here were in the shallows on the southern seaward reef of Ebadon, up at the other
end of the atoll. There they were common at the upper edge of the reef just under the breaking
waves.
Tortoise cowry
Chelycypraea testudinaria
A brownish gray mantle is mostly extended over the turtle-shell-colored shell. In snails, it is the
mantle that lays down the shell. In cowries, the mantle can cover the entire shell and this is what
keeps it so shiny. In terms of shell length, these are the longest cowries found here. A large
bulbous tiger cowry might exceed it in volume. They are found throughout the atoll, on the
seaward reef, lagoon pinnacles, lagoon shallow reefs, and even in the intertidal. But they are not
common in any of those areas.
Staphlaea cowry
Staphlaea staphlaea
One of the few cowries with a bumpy surface, Staphlaea staphlaea is usually hidden beneath its
mantle, which varies from black to red with white blotches. They live mostly on rubbly lagoon
pinnacles, but are also sometimes seen along the interisland lagoon reefs. They are usually under
rocks, often on the jet black sponge that they eat. This one is raising its mantle as it crawls along.
Punctate cowry
Notadusta punctata
This small cowry is also mostly found on lagoon pinnacles or reefs, but is occasionally observed
on seaward reefs as well. Here the mantle is mostly down, revealing the white shell bearing
brown spots.
Punctate cowry
Notadusta punctata
Here the mantle is fully raised, entirely covering the shell. The shell’s dark spots still show
through the not-completely-opaque mantle.
Martin’s cowry
Notadusta martini
This species was first described in 1907 from a few fossilized Philippine specimens. Kwajalein
was one of the places where fresh material was first found, during the late 1960s. Now they are
known to live well back in dark ledges on lagoon pinnacles, coming out close enough to be seen
only at night. Even then, they move quickly when exposed to light and often get away before a
photo can be taken.
Johnsons’ cowry
Palmadusta johnsonorum
This cowry is related to two other Indo-Pacific species, Palmadusta lutea and P. humphreysii.
There has been considerable confusion about the exact identities of these three species, but work
over the past 10 years or so has clarified the situation somewhat. So far, P. johnsonorum is
known only from the Marshalls, although its range likely extends farther. The species is rarely
found, usually on shallow lagoon reefs and pinnacles but occasionally on the seaward reef as
well. This one was under a rock on a pinnacle and is crawling among clumps of the green
tunicate eaten by the nudibranch Nembrotha cristata seen earlier in this video.
Red spindle eating top shell
Pleuroploca filamentosa
These red spindle shells are uncommon on lagoon pinnacles and on the seaward reef. This one is
eating the animal out of a top shell. This spindle has also been called Fasciolaria filamentosa.
Triton’s trumpet shell
Charonia tritonis
This is the largest shelled snail found here in the Marshalls. Never common, they are now
somewhat rare in areas frequently visited by divers. They get up to at least 18 inches long
(450mm) and have been seen on lagoon reefs, on pinnacles, and along the seaward reef.
Predators upon starfish, they may help exercise some control over the populations of reefdamaging, coral-eating crown-of-thorns and cushion stars, so they always should be left alone
when seen.
Legate cone with eggs
Conus legatus
This specimen was on a lagoon pinnacle, under a rock with its mass of egg capsules.
Aureus cone
Conus aureus
This is one of a number of cones at Kwajalein with shells bearing tent-shaped marks. Conus
aureus is primarily seen nocturnally on lagoon pinnacles, when it is out hunting for snails to eat.
The pink substrate to the right is a colonial tunicate.
Clandestine triton, thick periostracum
Cymatium succinctum
This used to have the name Cymatium clandestinum, which was very appropriate considering the
elongate, soft, flaps of periostracum that cover and effectively hide the shell.
Clandestine triton
Cymatium succinctum
Here the animal stretches out of its hidden aperture to try to pull the shell upright. You can
barely see the dark brown lines of the shell through the periostracum.
Fluted clam
Tridacna squamosa
This is the medium-sized giant clam species. Except when they are young, they are usually not
firmly attached to the substrate, although they may be secured by brown threads called a byssus.
The shells are more distinctly fluted than the other species, and the mantle color, while variable,
usually consists of some combination of spots or streaks. This one has thick yellow spots and
bands on a black background. The next few scenes show some of the many color patterns. While
these can be found on a variety of lagoon and seaward reefs, they seem most common on lagoon
pinnacles. A traditional food of the Marshallese, there are few of these attractive clams left near
inhabited islands.
Fluted clam
This one is yellow and tan on dark brown.
Tridacna squamosa
Fluted clam
Tridacna squamosa
Here the clam is mostly black sprinkled with yellow specks that increase in size toward the edge
of the animal.
Fluted clam
Tridacna squamosa
This one is black with light blue spots and streaks.
Fluted clam
Tridacna squamosa
On this one, the blue or yellow color seen in previous scenes is replaced by green.
Fluted clam
This one is mostly brown with yellow spots and black streaks.
Tridacna squamosa
Fluted clam
Tridacna squamosa
The blue-centered tan streaks and spots on dark brown make this one a striking sight. This clam
was found tipped over and partly buried in sand. It was propped upright after this clip was shot.
Giant and fluted clams
Tridacna gigas / Tridacna squamosa
The largest member of the giant clam family is Tridacna gigas. This scene shows an old, mostly
buried, empty T. gigas shell at left in the beginning of the scene, then a small T. squamosa, a
large T. gigas, and finally another T. squamosa on the right at the end of the clip. Apart from its
size, T. gigas can be differentiated from the others by the presence of small circles of iridescent
blue or green on its mantle. In the resolution of the video, these show up only as tiny greenish
spots, but you can’t miss them when you look closely at the real thing. These clams are slow
growing and, since they are another favorite food of the Marshallese, there are few to be found in
the southern portion of the atoll. There are still fairly healthy numbers in the middle of the atoll,
but even there we far too frequently see shells that have been recently emptied by fishermen.
Quite a few old friends that I have been visiting for as long as 37 years have ended this way.
These large giants are thought to live as long as 100 years. It seems almost criminal to end their
lives for the sake of a few calories.
Giant clam
Tridacna gigas
On the shell of this large Tridacna gigas, there is not only a bush of branching Pocillopora coral
growing (at right), but there is a small blue and black Tridacna maxima living on the larger
clam’s shell. Also, there is a small fluted Tridacna squamosa at the left end of the giant. Alas,
this is one of the old giants that was found fished out and empty in late 2010.
Giant clam
Tridacna gigas
Here is a large yellow one with coral growing up around it on a lagoon pinnacle.
Giant clam
A relatively small one on a shallow reef.
Tridacna gigas
Giant clam
Tridacna gigas
This is another we've been watching for more than 35 years. It seems almost been buried in live
coral.
Giant clam
This one has some especially bright green color.
Tridacna gigas
Giant clam
Tridacna gigas
This is another old giant that was discovered fished out in late 2010.
Giant clam
Tridacna gigas
Like corals, giant clams form a symbiotic relationship with zooxanthellae algae within their
tissues. The algae takes carbon dioxide produced by the clam's metabolism and uses it and
sunlight to produce oxygen and carbon compounds, which the clam "farms" for food. Most of
the clam animal's color comes from the algae. If that table coral left of the shell grows up and
shades the clam, the shaded part will lose its symbiotic algae and turn mostly white.
Giant clam covered with coral
Tridacna gigas
This old clam had been around a long time, long enough for several hefty colonies of coral to
grow up on its shell. The rounded coral colony to the left is heavy enough to pull the clam over.
Unfortunately, this one was near the other two fished out ones shown among the previous few
scenes, and it was fished out at the same time in late 2010. In all, in a single day fishermen
snuffed out five of the six known giants that were living on this large pinnacle reef.
Pennant bannerfish
Heniochus chrysostomus
Although they kind of resemble the banded Moorish idols, the several species of bannerfish
belong to the butterflyfish family. This species usually travels in pairs, but here a small group has
clustered over a colony of Goniopora coral on a pinnacle slope. The other common fish in the
scene is the green-banded staghorn damsel (Amblyglyphidodon curacao). The next few scenes
cover all the bannerfish known from Kwajalein.
Humphead bannerfish
Heniochus varius
This one has more dark brown color than the other bannerfish. Usually paired, this one is
hanging around a colony of stalk coral (Lobophyllia).
Longfin bannerfish
Heniochus acuminatus
The bannerfish with the long trailing dorsal fin is Heniochus acuminatus. At Kwaj, they are
usually found around deep lagoon reefs and shipwrecks.
Masked and Singular bannerfish
Heniochus monoceros / Heniochus singularus
This scene shows both masked, Heniochus monoceros, and singular bannerfish, H. singularus.
H. singularis, with more gray between the dark bands, white spots on some of the dark scales,
and a more distinct white band around the mouth, is in the foreground in this scene. It is rare
here, known from fewer than half a dozen sightings. It is so rare it probably cannot find mates of
the same species, so most of them have been hanging out with the similar H. monoceros.
Heniochus singularus has been seen on lagoon pinnacles and once on a shipwreck. It is a
relatively common species at Pohnpei.
Masked bannerfish
Heniochus monoceros
This large bannerfish is found on seaward and lagoon pinnacle reefs. Early in the scene there are
also a couple of raccoon butterflyfish (Chaetodon lunula).
Threadfin butterflyfish school
Chaetodon auriga
Although this common butterfly usually occurs in pairs on both seaward and lagoon reefs,
sometimes we see schools of them swarming around small isolated lagoon reefs.
Saddleback butterflyfish
Chaetodon ephippium
This is another common butterfly throughout the atoll. This one is feeding on sponges and other
benthic invertebrates exposed on an overturned bush of dead coral.
Lined butterflyfish
Chaetodon lineolatus
This is one of the largest butterflies and is also found on both lagoon and seaward reefs. They are
usually a bit shy and hard to approach.
Raccoon butterflyfish
Chaetodon lunula
These usually travel in pairs on lagoon and seaward reefs, but sometimes can occur in small
schools. It is known to eat a variety of benthic invertebrates including nudibranchs, and the latter
puts it on my “evil” list.
Blackback butterflyfish
Chaetodon melannotus
This species is not especially common, but is found throughout the atoll. It seems to mostly eat
soft corals and zoanthids, such as those in the scene.
Doublebarred butterflyfish
Chaetodon ulietensis
These are relatively common on lagoon and seaward reefs and usually travel in pairs.
Chevron butterflyfish
Chaetodon trifascialis
This species is strictly a live coral eater and is therefore not usually suitable for aquariums. They
tend to be loners and defend a specific territory, often a single table coral, against all other coral
eaters including their own species. However, sometimes you can see a couple of adults and
several juveniles apparently living in peace around a single coral colony. Very rarely we have
seen these in small schools, probably for mating purposes.
Teardrop butterflyfish
Chaetodon unimaculatus
It gets its common name from the single dark spot on each side, which in some specimens looks
like an inverted teardrop. These live on both lagoon and seaward reefs, often around large stands
of staghorn Acropora. They are reported to eat a wide variety of benthic invertebrates as well as
algae. This individual happens to be especially large and old.
Harlequin shrimp
Hymenocera picta
This is both a colorful species and one with interesting habits. They are nearly always paired,
with a large female accompanied by an often much smaller male. They often wave their wide
and gaudy chelipeds (claws) in some sort of display (to ward off predators, perhaps?) The shrimp
eats exclusively starfish, most often the small common Linckia, but we have also seen them eat
other species including the much larger crown-of-thorns (Acanthaster planci), which they may
ride around on and slowly dismember over a period of weeks. In Hawaii, these shrimp are a
brighter maroon color and are often found out in the open during the day, suggesting they may
have some chemical means of defense against predatory fish. The ones we see in the Marshalls
are less bright and always hide away under rocks. Why the difference? Unknown, except it is
true that Hawaii has few native groupers and snappers, fish that might be inclined to pick off
bottom-dwelling shrimp. Perhaps whatever has “trained” the species (that is, whatever selective
pressure is at work on them) here in the Marshalls is not present in Hawaii. Or, perhaps the
Hawaiian ones are distasteful. That might be a reason to investigate whether they are even the
same species.
Cone hermit crab
Ciliopagurus strigatus
This species of hermit crab has a very flattened body, well adapted to occupying shells with
narrow apertures that most hermits cannot fit into. Consequently, this is the crab that is usually
found inhabiting small cone shells such as this Conus retifer. The shell rests on a living colony of
Montipora coral.
Crinoid crab
Allogalathea elegans
The crab hidden at the base of the crinoid just to the right of the center of the screen is always
found associated with these feather stars. The crabs vary in color and usually match their crinoid
host very well.
Crinoid crab
Closer shot of the last scene.
Allogalathea elegans
Crinoid crab
Allogalathea elegans
Here the crab has turned around so we can see its long clawed appendages.
Sand shrimp
Trachypenaeopsis sp.?
These shrimp live under the sand by day, emerging at night to feed. When disturbed, they bury
back down again.
Cuming’s starfish
Neoferdina cumingi
This distinctive starfish lives under rocks or in ledges and small caves on seaward reefs and
pinnacles. Here it crawls across the multicolored undersurface of a rock. The colors are various
encrusting sponges and colonial tunicates.
Red starfish
Leiaster speciosus
Although covered with regular rows of small bumps, this star has a smooth, slimy feel to it. It is
found at night in small seaward reef and lagoon pinnacle ledges.
Starfish
Bothriaster?
This star has an interesting five points arranged in a pentagon around the middle of the star. Each
point lines up with one of the arms.
Starfish
Asteropsis carinifera
This nocturnal starfish usually hides in caves or under rocks during the day.
Starfish
Asteropsis carinifera
This is a small juvenile of the star in the previous scene. It sits on the multicolored undersurface
of a rock. The colored patches here are mostly encrusting sponges.
Yellowbanded pipefish
Corythoichthys flavofasciatus
This pipefish is common in a variety of lagoon and seaward reef habitats. Like other pipefish, its
small mouth is at the end of a long beak and is used to pluck small crustaceans and other food
from the bottom. It sometimes amazes me how well they can aim that mouth.
Conspicuous pipefish
Corythoichthys conspicillatus
This common pipefish is sometimes considered a form of the previous yellowbanded pipefish. It
seems to me that there are some consistent differences.
Schultz’ pipefish
Corythoichthys schultzi
This pipefish has an especially long snout. It is a common species on many reefs.
Schultz’ pipefish
Corythoichthys schultzi
A close-up of the head of Corythoichthys schultzi shows it nabbing an unseen tiny piece of food.
Pipefish
This frondose little pipefish is difficult to see in its algae habitat.
Halicampus mataafe?
Ringed pipefish
Dunckerocampus dactyliophorus
This species lives on seaward and pinnacle reefs in caves, where it usually hovers upside down
against the ceiling and slips out of sight when approached. This one is breaking the rules by
swimming around the floor of a small cave.
Threespot flounder
Samariscus triocellatus
This small flounder raises its upper pectoral fin and waves it around. The fish is well
camouflaged on the rubbly bottom.
Longlure flounder
Asterorhombus sp.
This species has an elongate first ray on its dorsal fin that extends out in front of the body in the
lower right side of the frame.
Longlure flounder
Asterorhombus sp.
Suspecting he has been seen, the flounder slowly turns away from the camera.
Scorpionfish
Scorpaena sp.?
Many scorpionfish have good camouflage colors and rest on the bottom until prey comes close.
Many species eat small fishes or shrimp.
Scorpionfish
This is likely a different color form of the species in the previous scene.
Scorpaena sp.?
Smallscale scorpionfish
Scorpaenopsis oxycephala
Profile shot. This scorpionfish has a set of intricate tufts and flaps over much of its body,
especially around the head. Like most scorpions, it is an ambush predator, lying in wait until
prey come near.
Spotfin lionfish
Pterois antennata
Lives on both lagoon and seaward reefs, where it usually sits upside down on cave ceilings. The
dorsal spines are quite venomous and produce a painful sting. Toward the end of the clip, the
spots in the pectoral fins are evident, showing where the common name comes from.
Clearfin lionfish
Pterois radiata
This is the other common small lionfish, and it too can give a painful sting from the dorsal
spines.
Stonefish mostly buried
Synanceia verrucosa
The fish is hard to see in this scene. It is buried in sandy rubble up to its face, but its eyes, mouth,
and first dorsal spine are exposed. In fact the fish takes up most of the frame, but is very difficult
to distinguish from any other pile of rubble. The fish lies in wait for prey to pass by. When
feeding, it opens its cavernous mouth and the prey disappears inside. The spines on this fish are
highly venomous and have cause human fatalities.
Stonefish walking
Synanceia verrucosa
Having been coaxed out of the sand, the stonefish hops along the bottom, using its fins almost
like feet. They rarely take the trouble to actually swim.
Octopus hunting
Octopus cyanea
Octopus spend much of their time in dens, but will sometimes come out and hunt during the day.
This one is going from rock to rock, changing color and spreading its various arms into nooks
and crannies, trying to drive out any crustaceans or small fish. It catches them in the thin,
balloon-like membrane between its tentacles. A yellow wrasse hangs around in case anything
bite-sized escape the octopus net. It is a somewhat dangerous business for the octopus; some eels
living in the holes feed on octopus arms.
Octopus hunting
More of the same from the previous scene.
Octopus cyanea
Octopus
Octopus cyanea
They go from rock to rock to reach underneath for food. They sometimes don't seem to care if a
diver watches.
Goggle-eye
Priacanthus hamrur
These nocturnally active fish can be found by day either hovering low over coral, which they
will ease under when approached too closely, or in large schools on the slopes of some lagoon
pinnacles. Individuals can quickly change from silvery to red and back, both forms shown in this
scene.
Goggle-eye
An especially bright red one.
Priacanthus hamrur
Goggle-eye school
Priacanthus hamrur
A large school on a lagoon pinnacle.
Parrotfish over table coral
Several parrotfish pass over a large table coral
Parrotfish feeding on reef
A mixed group of parrotfish graze algae from a pinnacle reef. Most of the green ones are
Chlororus microrhinos. Two kinds of rabbitfish are also present.
Steephead parrotfish
Chlororus microrhinos
A small school of Chlororus microrhinos streams along over dense coral growth.
Blackfin hogfish
Bodianus loxozonus
The common name apparently comes from the black pelvic fins. These are uncommon at Kwaj,
seen sporadically on some lagoon pinnacles and seaward reefs. They can feed on small snails and
hermit crabs by crushing their shells with their powerful jaws.
Checkerboard wrasse
Halichoeres hortulanus
This is a common wrasse on lagoon and seaward reefs. Like many wrasses, it rarely stops
moving long enough to focus on it.
Allen’s wrasse
We see these mostly on deep lagoon reefs and the slopes of lagoon pinnacles.
Labropsis alleni
Orbicular batfish
Platax orbicularis
This is a pair of the young orbicular batfish (Platax orbicularis), one of at least two species of
batfish found at Kwajalein. These are most often found on lagoon reefs and pinnacles, as well as
around lagoon shipwrecks. Neither of the books I referenced called these “batfish,” no doubt
because there is a very different kind of bottom-dwelling fish that is also called a batfish. One
book uses “platax” as a common name, while the other goes with “spadefish.” However, we here
at Kwaj have always referred to them as batfish, so I will continue to do so here. This is yet
another example of why it is best to use the scientific name.
Orbicular batfish
The batfish are often quite curious and will come right up to a diver.
Platax orbicularis
Orbicular batfish
As they get larger, their banding fades somewhat.
Platax orbicularis
Mostly orbicular batfish
Platax orbicularis
They sometimes occur in small schools around some lagoon pinnacles. Sometimes the schools
include both species. The one at the very top of this scene is the other species, the blunthead
batfish (Platax tiere). Adults of both species look similar, but P. tiere have yellow pelvic fins
and a dark black spot at the base of thedark vertical band behind the eye.
Blunthead batfish
Platax tiere
The two close ones and several behind are this species; note the yellow pelvic fins and black spot
at the base of the dark band behind the eye. The rest are Platax orbicularis.
Orbicular batfish
A very friendly one comes in to take a close look at the camera lens.
Platax orbicularis
Dogtooth tuna
Gymnosarda unicolor
The dogtooth is a favorite catch for the fishermen. While normally a highly edible fish, under
some circumstances these can develop a fish poisoning called ciguatera. Ciguatera is caused by
poisonous single-celled algae that grow on the reef, and which seem especially attracted to
“new” or fresh surfaces (new shipwreck, construction site, storm damaged reef, etc). Grazers like
parrotfish and tangs pick these algae up in their diet. Predators who eat a bunch of grazers
concentrate the toxin in their bodies, and higher-level predators concentrate it even more. Most
dangerous are carnivores that eat carnivores. Some of the worst are large groupers, large
snappers, moray eels, large jacks and barracuda. Larger individuals tend to be worse since they
eat more and have been around longer to build up the toxins. Dogtooth tuna, because they are
carnivores and hang around reefs, have been known to pick up ciguatera. Studies done in the
Marshalls some years ago found feeding the internal organs of dogtooth tuna to test animals
(mongoose) sometimes elicited a moderate ciguatera reaction. Internal organs tend to harbor a
larger concentration of ciguatera toxins. The actual flesh of the fish is probably safe most of the
time; just don't eat the organs or skin.
Barcheek jack
Carangoides plagiotaenia
This fast-moving predatory jack can be found on both seaward and lagoon reefs. The common
name comes from a dark bar on the side of the face just below and behind the eye. This particular
jack always strikes me has having a rather sour look on its face.
Double-lined mackerel
Grammatorcynus bilineatus
This one stopped on top of a lagoon pinnacle to have its parasites picked off by a Labroides
dimidiata. Note the cleaner wrasse checking out its client's gills, which the mackerel is helpfully
exposing.
Rainbow runner school
Elagatis bipinnulata
Schools of these can be found on both seaward and lagoon pinnacle reefs. It is a popular fish for
eating.
Mackerel scad
Decapterus macarellus
A school rises up the side of a pinnacle, joining some larger rainbow runner at the end of the
scene.
Neon fusiliers over fire coral
Pterocaesio tile
A school streams past a stand of fire coral (Millepora) surrounded by Halimeda algae and other
corals.
Neon fusilier
Pterocaesio tile
Many fish swarm in front of the camera with a dense living coral slope in the background.
Neon and Marr's fusiliers
Pterocaesio tile
A school streams past over coral and accompanied by a few Marr’s fusiliers (Pterocaesio marri).
Again, some of the lagoon pinnacles are densely covered with living corals.
Marr’s & Neon fusiliers
Pterocaesio marri
A school of mostly Marr's fusiliers streams towards and past the camera over a field of staghorn
coral. A few neon fusiliers (Pterocaesio tile) are mixed into the school. It is not uncommon to
see two or even three different species of caesonids mixed into a single school.
Marr’s fusiliers
With a few neon fusiliers (Pterocaesio tile).
Pterocaesio marri
Scissortail fusilier
Caesio caerulaurea
The body resembles Marr’s fusilier but the tail is quite different. In the center of the photo is a
colony of Pacific Elkhorn coral (Acropora rotumana), reported in the press to be recently
"rediscovered" at nearby Arno Atoll after having not been seen for 100 years. Seen by whom?
The coral is common in the southern Marshalls and Kwaj divers have been swimming over it and
photographing it for many years. I guess we just didn't tell the right people.
Blue & yellow fusiliers
This school swims over a large table on a pinnacle slope.
Caesio teres
Blue & yellow fusiliers
Again, these are swimming over a large table on a pinnacle slope.
Caesio teres
Threeline fusiliers & anemones
Pterocaesio trilineata
A school swarms around a reef bearing two large magnificent anemones (Heteractis magnifica).
A few bluestriped snappers (Lutjanus kasmira) and other fish swim around the reef as well.
Whitetip shark
Triaenodon obesus
This one comes up the side of a lagoon pinnacle and turns to go back down. Whitetips, although
sometimes curious, are not aggressive unless spearfishing is taking place.
Whitetip shark
This one passes by on top of a midlagoon pinnacle.
Triaenodon obesus
Whitetip sharks in cave
Triaenodon obesus
The camera zooms out from a small one hiding with several others under a large dead table coral.
Gray reef shark
Carcharhinus amblyrhynchos
While filming a peaceful reef scene, a gray reef suddenly swims into the frame and heads up
towards the surface.
Gray reef shark
Carcharhinus amblyrhynchos
A slightly agitated gray reef swims past. As mentioned earlier, gray reefs have a peculiar and
easily recognized swimming behavior called "posturing" when they are territorially aggressive.
There are a number of different stages of the posture, and with practice a diver can tell if a gray
is simply swimming past or is showing even a hint of territorial aggression. A full-on, all out
posture is unmistakable, but it is not easy to see that the shark in this scene is showing the bare
beginnings of posturing behavior.
Gray reef shark
Carcharhinus amblyrhynchos
This one speeds up the slope of a lagoon pinnacle past the camera.
Gray reef shark
Carcharhinus amblyrhynchos
Gray reef shark
Comes in for a close pass.
Carcharhinus amblyrhynchos
Lagoon reefs
Spotted eagle ray feeding
Aetobatus narinari
These rays come down to the bottom to feed. They are known to eat primarily bivalve and
gastropod mollusks (clams and snails), which they crush with their powerful jaws. They may eat
other burrowing animals as well. In Reef and Shore Fishes of the Hawaiian Islands, Dr. John
Randall reports that one specimen of this circumtropical species collected in the Virgin Islands
had the animals from 41 juvenile Queen conchs in its stomach with not a trace of a shell. The
shell fragments must have been effectively spit out when the ray crushed them. Queen conchs are
roughly the size of our giant finger shells (Lambis truncata). Young specimens have thin shells,
so even our finger shells are probably readily crushed up by these rays around here. The ray in
the clip digs up something on a lagoon algae patch, then chews something up and spits out a few
shell fragments as it swims by.
Spotted eagle ray & remora
Accompanied by a sharksucker (Echeneis naucrates).
Aetobatus narinari
Porcupine ray feeding
Urogymnus asperrimus
These large rays are covered with hard, thorny warts, giving it its common names of porcupine
or thorny ray. Like many of the stingrays, they feed on benthic invertebrates buried in the sand,
which they dig up, raising a cloud of silt in the process. This species tends to be a bit shy of
divers and is difficult to approach. It takes off when it notices the cameraman through the cloud
of silt.
Porcupine ray feeding
Urogymnus asperrimus
This one is digging in the sand while accompanied by a couple of sharksuckers (Echeneis
naucrates). While most stingrays have a venomous spine on their tail, this species does without.
Porcupine ray
Urogymnus asperrimus
Wary of the cameraman approaching from above, this one turns tail and swims away.
Pink whipray
Himantura fai
This one is commonly called the pink whipray because in some areas it is pinkish in color, but
here it is usually gray-brown. These are not uncommon along some lagoon sandy reefs. This one
is accompanied by a jack, which is hoping the feeding ray may scare up some prey it can steal.
This ray does have single venomous spine.
Pink whipray feeding
Himantura fai
This one digs in a patch of Halimeda algae. It also has a couple of tagalong jacks hoping for a
free meal.
Fantail stingray
Pastinachus sephen
These are found on some sandy lagoon reefs. They can easily be recognized by the thin fan of fin
near the end of the tail. This one also bears venomous spines on the tail. Up to 20 or more small
individuals have been observed all at once in the shallow sandy bottom of Kwajalein’s harbor,
between the boat ramp and the moored boats. Larger ones are out on the lagoon slope. This one
swims off with a sharksucker (Echeneis naucrates) attached to the base of the tail.
Burrowing echinoid
Brissus sp.?
This could be one of the prey items the stingrays shown earlier are seeking. These burrowing sea
urchins live most of their lives under the surface of the sand. When exposed, they immediately
start digging back down again.
Burrowing echinoid
This one is about halfway dug in again, and is still digging.
Brissus sp.?
Helmet shell
Cassis cornuta
One animal that definitely feeds on burrowing echinoids such as the one shown previously is the
sand-dwelling helmet shell. Sometimes in sandy areas you can find a trail of empty echinoid
shells leading to one of these helmets. Helmets are often buried in the sand with only the back of
the shell visible. This helmet is a young one, and so far little growth has accumulated on its
colorful shell.
Helmet shell
Cassis cornuta
This is a larger helmet shell. The only clean part of the shell is that which is normally buried in
the sand. The exposed upper part of the shell is encrusted with various growths.
Helmet shell
Cassis cornuta
Helmets lay their masses of brown egg capsules attached to clumps of algae or rocks in the sand
flats.
Bonnet shell
Casmaria ponderosa
These nocturnal bonnet shells also eat burrowing echinoids, which will sometimes come out of
the sand and try to run away on their little spines. The bonnets are much faster, however. These
bonnets are in turn eaten by stingrays and, we suspect, octopus. Sometimes you find a pile of
empty bonnet shells where it looks as though some predator had gathered a bunch of them up
and plucked out the animals. I'd like to actually see it happen, but in my mind's eye I can imagine
a nocturnal sand-dwelling octopus gathering up a bunch of these in its tentacles and settling
down in one place to have a feast.
Bonnet shells mating
Casmaria ponderosa
It looks as though the bonnet on the back might be a male trying to mate with an apparently
reluctant female.
Bonnet shells mating
A third bonnet shell, probably also a male, joins the fray.
Casmaria ponderosa
Tun shell
Tonna canaliculata
Although similar to the common partridge tun shell, this tun is rare here at Kwaj. We have seen
only this one living specimen and a couple of empty shells. They live on sandy lagoon reefs,
buried deep under the sand by day.
Mutated conch
Strombus mutabilis
The shells on this common conch are highly variable, and this individual is especially intricately
colored. From the anterior end (right side), two eyestalks and a long proboscis extend. The
mouth is at the end of the proboscis and is used to graze on algae.
Mutated conch
Strombus mutabilis
Here the animal extends from the aperture in an attempt to turn the shell upright.
Bloodmouth conch
Strombus luhuanus
This species is abundant on sandy and rubbly lagoon reefs. It gets its common name from the red
color inside the aperture, although some are yellow or white. The two eyestalks are at the
anterior end (at right). The animal quickly rights the shell by extending its foot, digging its horny
operculum on the end into the sand, and pushing outward, causing the shell to flip upright.
Silver conch
Strombus lentiginosus
This animal rights itself in much the same way as the Strombus luhuanus in the previous scene.
Bull conch
Strombus taurus
The known range of Strombus taurus is limited to the northern Marshalls and Marianas Islands.
At Kwajalein, it mostly lives along the east reef in the middle of the atoll.
Distorted anal triton
Distorsio anus
You might think the person who named this one had a warped sense of humor. However, "anus"
in Latin means "an old woman." So should this be the distorted old woman triton? In this scene,
the crosshatched animal stretches out of its aperture to pull the shell upright.
Love harp
Harpa amouretta
These fast moving predators live on a variety of lagoon and seaward reefs, but seem most
common in patches of Halimeda algae along sandy lagoon slopes. They typically bury in sand
during the day. We have seen them eating small, shelled gastropod mollusks.
Harp shell
Harpa harpa
Larger and more brightly colored than the previous Harpa amouretta, this is a rare species at
Kwajalein. A few specimens have been seen at night along sandy lagoon Halimeda patches and
several broken or crab-inhabited shells have been found on the steep seaward reef.
Oak cone
Conus quercinus
These cones live in sand, often around patches of Halimeda algae, along lagoon reefs. In some
areas they are quite common, and we have seen clusters of 30 or more mating and laying egg
masses.
Planorbis cone
Conus planorbis
Conus planorbis is rarely seen here, but it is similar in appearance to a common cone named
Conus vitulinus.
Marble cone with eggs
Conus marmoreus
This is primarily a lagoon-dwelling cone—a similar shell seen on the seaward reef is a different,
though related, species. They can be found living in sand under rocks or more commonly
exposed in patches of Halimeda algae along lagoon slopes. This one is in the process of laying
down its egg capsules. Each of these light gray capsules contains a number of Conus marmoreus
eggs.
Omaria cone
Conus omaria
We saw some cones earlier with tent markings (e.g., Conus aureus) and there are a number of
species found primarily along lagoon reefs. Conus omaria can be found in sand under rocks or
crawling about in Halimeda patches. It seems that cones with these triangular or tent shaped
markings primarily eat other seashells.
Admiral cone
Conus ammiralis
I think this is one of the prettiest of the cones with tent markings. It is seen most often in and
around patches of lagoon Halimeda algae.
Carnelian cowry
Lyncina carneola
This is a relatively common species on a variety of lagoon and seaward reefs.
Caurica cowry
Erronea caurica
This medium-sized cowry is common on lagoon reefs and pinnacles, where it lives under rocks.
Clandestine cowry
Palmadusta clandestina
This is one of the small cowries, and is usually found along lagoon reefs under rocks or in
patches of Halimeda algae. The mantle covering the shell ranges from orange to black in
different specimens. This one is crawling over a colony of sponge in a sandy Halimeda patch.
Sieve cowry
Cribrarula cribraria
Sieve cowries are usually seen under rocks on intertidal or shallow subtidal lagoon reefs, where
they eat a red sponge that is the same color as the cowry’s mantle. Sometimes they are found on
patches of red sponge on shipwrecks.
Eroded cowry
Erosaria erosa
This common species is usually seen under rocks intertidally or on shallow subtidal lagoon reefs.
Fringed cowry
Purpuradusta fimbriata
This tiny cowry can be found throughout the atoll, usually under rocks by day or crawling in
ledges and caves with its red mantle extended at night.
Strawberry or honey cowry
Erosaria helvola
The strawberry is a very common intertidal and shallow subtidal species that usually lives under
rocks or in patches of Halimeda algae. I think only at Kwaj is it called a strawberry. The usual
common name is honey cowry. This one is crawling about with its mantle rising on the
undersurface of a rock that is thickly covered with sponges, tubeworms, and other animals.
Swallow cowry
Bistolida hirundo
Another of the small species, Bistolida hirundo is uncommonly found under rocks on shallow
lagoon and pinnacle reefs.
Lab cowry
Erosaria labrolineata
Although this species is mostly quite uncommon on seaward and lagoon reefs, it is sporadically
common under rocks or in Halimeda patches in a few areas.
Lynx cowry
Lyncina lynx
This medium-sized cowry is mostly common under rocks intertidally and on shallow lagoon
reefs and pinnacles. It is only rarely found on the seaward reef.
Map cowry
Leporicypraea mappa
A relatively large cowry, maps can be seen in caves on the seaward reef at night or under rocks
by day on lagoon reefs and pinnacles. Judging by the number of empty shells, it is also prevalent
on lagoon-bottom shipwrecks, although there it is rarely seen alive.
Money cowry
Monetaria moneta
This is the most abundant cowry at Kwajalein and probably throughout the Indo-Pacific.
Typically it lives exposed on intertidal reef flats, but can also be found under rocks on shallow
lagoon reefs and pinnacles, as well as in Halimeda patches.
Stolid cowry
Bistolida stolida kwajaleinensis
This reddish brown form of the widely distributed stolid cowry appears to be unique to
Kwajalein, or at least to the Marshall Islands. In most areas, this shell has a bluish gray tint.
Stolid cowry
Bistolida stolida kwajaleinensis
This Kwajalein stolid has its mantle completely covering the shell.
Wentletrap
Epitonium sp.
Earlier in the video we saw some wentletraps that eat fungiid corals. There are also species that
parasitize sea anemones, like this one here with a piece showing of the large anemone
Stichodactyla haddoni.
Wentletrap
Epitonium sp.
Here are three more of the same species of shell with a cluster of their egg masses, which they
mix up into balls of sand.
Haddon’s anemone with anemone fish
Stichodactyla haddoni
This is the kind of anemone the wentletraps in the previous scene were parasitizing. While not
the same day or the same anemone, this one also evidently has its wentletrap parasites hidden
underneath. Just beyond the lower to lower right edge of the anemone’s disk you can see the
rounded sand balls that form the egg masses for wentletraps. The fish in the anemone include
threestripe clownfish (Amphiprion tricinctus) and threespot damsels (Dascyllus trimaculatus),
which are typically the anemonefish found in this kind of anemone here at Kwaj. Although we
have noted it in several of our videos, Haddon’s anemone has never been officially reported in
the scientific literature from the Marshall Islands. Yet it is not rare in lagoon sand flats and
Halimeda patches.
Haddon’s anemone with anemone fish
Stichodactyla haddoni
This species of anemone varies somewhat in color. This all brown one is occupied by a number
of small threestipe clownfish (Amphiprion tricinctus) and threespot damsels (Dascyllus
trimaculatus). There are also some blue damsels (Pomacentrus coelestis) off to the left, possibly
taking advantage of the protection from predation offered by predators avoiding the anemone’s
sting but they need to be careful not to be stung themselves.
Haddon’s anemone with anemone fish
Stichodactyla haddoni
Here is a mottled Haddon’s anemone in a lagoon Halimeda patch hosting some larger threestripe
clowns and threespot damsels.
Haddon’s anemone with anemone fish
Stichodactyla haddoni
Most often, the threestripe clowns and threespot damsels in Haddon’s anemones are juveniles,
but these clowns at least look as though they are getting pretty large. At some point, they
probably wander off to find their own anemones, usually Entacmaea quadricolor anemones.
Most probably get picked off by predators while they are looking.
Haddon’s anemone with anemone fish
Stichodactyla haddoni
In addition to the usual threestripe clowns, this anemone also has a juvenile threadfin
butterflyfish (Chaetodon auriga) hanging around. It must be careful not to touch the anemone’s
stinging tentacles.
Haddon’s anemone with anemone fish
Stichodactyla haddoni
Haddon’s anemone also comes in a rare bright red or orange color form. In addition to the usual
threestripe clowns and threespot damsels, this anemone is also protecting some juvenile
butterflyfish, including a threadfin (Chaetodon auriga) and several Klein’s (Chaetodon kleini).
Risky business for the baby butterflies.
Haddon’s anemone with anemone fish
Stichodactyla haddoni
Again lots of clowns and damsels, along with a juvenile threadfin butterfly.
Haddon’s anemone with anemone fish
This is an unusual pink color for the anemone.
Stichodactyla haddoni
Haddon’s anemone with anemone fish
Stichodactyla haddoni
A close-up showing the multitudes of juvenile threestripe clowns. How could they possibly all
find their own anemones when it comes time to strike out on their own?
Handnet crab
Neopetrolisthes maculatus
This handnet crab is always found with one of several species of anemone, and nearly every
Haddon’s has its own resident pair. The crabs may hide under the edges of the tentacle-covered
oral disk so are often hidden from view. These crabs get their common name from their feeding
technique. The large, fierce-looking claws are rarely used for feeding. Instead, specialized
forward appendages are terminated with many close-set, long, slightly curved filaments that the
crab uses to scoop plankton out of the passing water currents. After holding up the “handnet” for
a few seconds, the crab retracts it and uses small brush-like appendages next to the mouth to
scoop any plankton from the net and transport it to the mouth.
Handnet crab feeding
Neopetrolisthes maculatus
Here is another feeding handnet crab in a mostly white Haddon’s anemone.
Handnet crab
Neopetrolisthes maculatus
The big claws may be used mostly for protection. The anemone’s resident threestripe clowns
sometimes give the crabs a hard time.
Handnet crab feeding
Neopetrolisthes maculatus
But sometimes the handnet crab’s claws seem to be used for feeding. This one was using them to
hold a nearby clump of algae while it scoured it for food.
Holthuis’ shrimp in Haddon’s anemone
Periclimenes holthuisi
Another regular inhabitant of a number of anemones and even a few corals is this nearly
transparent shrimp. It looks like it is walking over a field of pink balloons.
Holthuis’ shrimp in fire anemone
Periclimenes holthuisi / Actinodendron plumosum
This shrimp is hovering over the stinging tentacles of this sand-dwelling anemone.
Short-clawed shrimp in Haddon’s anemone
Periclimenes brevicarpalis
Most Haddon’s and a few other anemones often support a mated pair of these mostly transparent
shrimp. We saw some of these earlier in this video on sticky sucker anemones (Cryptodendrum
adhaevisum).
Short-clawed shrimp in Haddon’s anemone
Periclimenes brevicarpalis
The female is usually larger and is often seen carrying a clutch of eggs under her abdomen.
Short-clawed shrimp and handnet crab
Periclimenes brevicarpalis
This shrimp appears to get startled by a feisty handnet crab (Neopetrolisthes maculatus) coming
up from a fold in the anemone’s edge. The crab kind of reminds me of grumpy troll coming up
from under a bridge.
Yellow frogfish
Antennarius coccineus
This is usually referred to in the aquarium trade as the scarlet frogfish (or anglerfish) because of
its sometimes red color form. It also comes in yellow, brown, or green. The ID is tentative. Often
a closer look at some anatomical features is necessary to separate the frogfish species, many of
which are variable in color and superficially resemble one another. The tufts on the chin and
cheeks of this yellow fish are similar to the figure in Scott Michael’s Reef Fishes, volume 1.
Frogfish are ambush predators, usually resting motionless on the bottom until a prey comes close
enough to grab. Then, hardly seeming to move, the frogfish engulfs the prey, which can be a fish
as long or longer than the predator. The stomach of this beast is quite expandable. They also
have a “fishing lure,” consisting of a thin rod called an illicium extending from the first dorsal
spine and tipped with a chunk of “bait” called an esca. Waving the bait around in front of the
mouth attracts fish in close enough to be swallowed. In still photos of this specimen, we have
seen that the esca of this animal is a small, white, studded ball, which matches that reported for
A. coccineus.
Yellow frogfish
Antennarius coccineus
This is a smaller individual of the species from the previous scene. Rather than swim, frogfish
often “walk” along the bottom using their pectoral and pelvic fins.
Red frogfish
Antennarius coccineus
This one could be a red color form of the previous species, but the presence of the large spot
under the dorsal fin is more characteristic of its close relative, Antennarius nummifer. Not visible
in the video is the fishing lure, which still photos of this animal showed to be a white, studded
ball like that of the yellow specimens above rather than the filamentous one usually present on A.
nummifer. An expert may be able to distinguish them from pictures, but I would need to collect a
specimen to look at its anatomical features. But they are hard enough to find here and I enjoy
seeing them in their natural habitat, so I am reluctant to pull one out of the water.
Red frogfish
Antennarius coccineus
When frogfish do swim, they rarely use their fins. Instead, they use jet propulsion. They draw
water into their cavernous mouths, then close the mouth and force the water out through small
gill openings that happen to be located in their “armpits”—well, just behind their pectoral fins,
but they kind of look like armpits. This causes them to hop along in short bursts.
Painted frogfish
Antennarius pictus
This one also does not exactly fit the descriptions of any other species I know. The spotting and
fishing lure might make it A. pictus. It could also be a small specimen of the giant frogfish,
Antennarius commerson. So far we have seen only two like this; this one was resting on a chunk
of orange-brown sponge out in a Halimeda patch and the other was nestled within Halimeda
algae.
Painted frogfish
Closer view.
Antennarius pictus
Reticulated frogfish
Antennarius tuberosus
Finally, an easy frogfish to identify. We have found a couple of these, resting up against small
rocks or pieces of sponge in lagoon Halimeda patches.
Black frogfish
Antennarius commerson?
This is the largest frogfish we have yet seen here. It measured about 100mm. In other places, A.
commerson can reach nearly four times that length. However, this could also be the same species
as the one we tentatively called Antennarius pictus above. A close look at the body shows the
presence of similar spots, and the fishing lure is also similar. We have seen only one of these,
and it was in a lagoon Halimeda patch.
Black frogfish
In a head on view, it is hard to recognize it as a fish.
Antennarius commerson?
Snowflake eel
Echidna nebulosa
We do not see this pretty eel often, but one spot near Bigej Island seems to have a good
population of them. They usually live under rocks on shallow rubbly reefs.
Yellowmargin moray eel
Gymnothorax flavimarginatus
The tail of this moray, which you usually do not see, has a distinct yellow to orange margin to
the fins. These eels are usually found on lagoon rather than seaward reefs, and it is a fairly large
species. The schooling fish darting around behind the eel’s head are pygmy sweepers
(Parapriacanthus ransonneti).
Marbled snake eel
Callechelys marmorata
This bizarre-looking snake eel spends most of its time under the sand and is rarely seen. This one
poked its head up on a lagoon sandspit. We’re not sure why it is breathing so hard, or why all the
tiny hermit crabs are coming around. Maybe the eel has some attractive (to crabs) bad breath.
Marbled snake eel
Closer view.
Callechelys marmorata
Tubeworms
These appear to be the crowns of tubeworms in the family Sabellidae. We see these fairly
frequently in patches of Halimeda algae on sand. As one crown comes slowly out, another is
quickly retracted.
Flatworm
This one crawled out of Halimeda algae on a lagoon sandy reef.
Pseudoceros jebborum
Flatworm
Pseudoceros jebborum (left) / Pseudobiceros sp. (right)
The one on the left appears to have a full stomach.
Flatworm
Pseudobiceros?
This is another that was living in a lagoon Halimeda patch. It is difficult to properly preserve and
study flatworms, so many species are still unknown and probably scientifically unnamed.
Red flatworm
Pseudoceros?
This deep red one was small, only about 10mm long, and was seen crawling over fine algae on a
lagoon sand falt.
Fulgor flatworm
Pseudobiceros fulgor
This one appears to have eaten recently as its abdomen is bulging. It also is regenerating on the
left side of the image from some damage. These very thin flatworms are only a few cells thick,
making them quite fragile and easy to break up. This individual is crawling across an orange
encrusting sponge that bears very distinct branching channels.
Red pecten
Mirapecten?
The shell is similar to Mirapecten rastellum, but the red animal is unusual. This may be an
unknown species. Like most pectens, it swims away by rapidly flapping its valves when
disturbed.
Pallium pecten
Gloripallium pallium
This is one of the larger pectens at Kwaj and is usually under rocks on lagoon subtidal reefs. It
too swims away when disturbed.
White pecten
Brachtychlamys?
This species lives in lagoon Halimeda patches. None of these pectens like to be exposed and will
try to swim away.
Irregular pecten
Chlamys irregularis?
With the thick red coat on the shell, it is hard to be sure of the species. It could also be Chlamys
limatula.
Irregular pecten
With the thick blue coat on this shell, it is hard to be sure of the species.
Chlamys irregularis?
Irregular pecten
This one seems to have extremely long tentacles.
Chlamys irregularis?
Smooth pecten
Dentamussium obliteratum
These pectens usually live deep on the slopes of lagoon pinnacles under rocks or coral. Although
this one gets caught in rocks when it tries to swim away, they are normally extremely good
swimmers that can disappear in an instant if you take your eye off them.
Giant clam
Tridacna gigas
This is a young one in a lagoon slope Halimeda patch we have been watching grow for the past
few years. The little green circles characteristic of the real giant clam are evident in this clip.
Giant clam
We have also been watching this one grow over the past few years.
Tridacna gigas
Giant & fluted clams
Tridacna gigas / Tridacna squamosa
Here a large giant clam and smaller fluted clam grow adjacent to each other.
Magnificent anemone & giant clam
Heteractis magnifica / Tridacna gigas
This is the giant clam from the previous scene viewed from the other direction. A large
magnificent anemone lives alongside the clam.
Magnificent anemone
Heteractis magnifica
This is a large yellow one with a few inconspicuous apricot clownfish (Amphiprion perideraion).
Magnificent anemone balled up
This one is all balled up, showing off its purple stalk.
Heteractis magnifica
Magnificent & crispa anemones
Heteractis magnifica / Heteractis crispa
This large anemone on top of a small lagoon reef appears to host both apricot (Amphiprion
perideraion) and twostripe clowns (Amphiprion chrysopterus), but in fact the latter are living in
a crispa anemone (Heteractis crispa) barely visible at the lower left side of the screen. This is
one of the few H. crispa anemones we know of in the lagoon; they are more common on the
seaward reef.
Corkscrew anemone
Macrodactyla doreensis
This is another anemone that has not officially been reported from the Marshalls in the scientific
literature. Here they are usually found on lagoon slopes in Halimeda patches, where they may
host some commensal shrimp, threestripe clowns (Amphiprion tricinctus), and threespot damsels
(Dascyllus trimaculatus). The common name of the anemone is derived from the corkscrew
shape of some of the tentacles.
Cauliflower anemone & cardinalfish
Actinodendron plumosum
These anemones pack a powerful sting and usually do not host commensal anemonefish.
However, they usually have some commensal shrimp. Around this one, though, a school of
yellow cardinal fish (Apogon luteus) has gathered, along with a few blue damsels (Pomacentrus
coelestis). Another common name for a cauliflower anemone is fire anemone.
Clumpy nudibranch
Asteronotus cespitosus
This large, lumpy nudibranch is found occasionally under rocks on intertidal and shallow
subtidal lagoon reefs.
Funeral nudibranch
Jorunna funebris
This striking nudibranch is sometimes found eating a blue sponge on shallow lagoon and
seaward reefs. “Funebris” is Latin for funeral, but I have no clue why the original author gave it
that name.
White-cross nudibranch
This nudibranch lives under rocks on shallow lagoon reefs.
Halgerda albocristata
Cryptic nudibranch
Hallaxa cryptica
This common nudibranch is rarely noticed because it so closely resembles its normal food
sponge.
Bulls-eye nudibranch
Hoplodoris estrelyado
This one has an interesting pattern of concentric circles surrounding bumps. It lives under rocks
on lagoon and pinnacle reefs.
Warty nudibranch
Hoplodoris grandiflora
We have seen this species under rocks on lagoon and seaward reefs, and also in lagoon Halimeda
patches.
Nudibranch
Asteronotus raripilosa
The only specimen of this large nudibranch we have seen so far was crawling on Halimeda algae
at night.
Formosan nudibranch
Platydoris formosa
This rather large, flattened, stiff species is found under rocks on intertidal and lagoon reefs, as
well as crawling in lagoon Halimeda patches.
Scab nudibranch
Platydoris scabra
This large nudibranch is relatively common under large rocks in very shallow water along lagoon
reefs. This individual happens to be on the dark end of the scale. They are usually lighter in color
with more white patches.
Tubercular nudibranch
This red species is easy to mistake for a clump of red sponge.
Sclerodoris tuberculata
Long-tail nudibranch
Ceratosoma tenue
So far we have found these only in lagoon Halimeda patches along the east reef, where they are
not especially rare.
Three-lobed nudibranch
Ceratosoma trilobatum
Related to the animal in the previous clip, this one is known from only two specimens, one on
sand and the other on a reef, both near Gugeegue Island.
Purple & yellow nudibranch
Chromodoris aureopurpurea
The color consisting of purple-black spots within larger yellow blotches along the margin of the
animal distinguishes this species from a couple of similar ones. The few specimens known from
Kwajalein all were found on Halimeda algae or sand on sandy lagoon slopes.
Yellow nudibranch
Chromodoris sp.
This species is similar to a more widespread one called Chromodoris rubrocornuta, but only
from Kwajalein do they have the rich yellow dorsum. These are known from lagoon reefs and
pinnacles.
Geometric nudibranch
Chromodoris geometrica
This species can be seen on occasion on a variety of seaward and lagoon reefs. It is one of the
few species here that is usually found in the open during the day.
Hintuan nudibranch
Chromodoris hintuanensis
This species is known in the Marshalls from only five specimens, all found hiding in Halimeda
algae on sandy lagoon slopes.
Seto nudibranch
Chromodoris setoensis
This nudibranch is usually found on lagoon reefs and pinnacles, but a few have been seen on the
seaward reef.
Blackmargined nudibranch
Glossodoris atromarginata
This species can be found on a variety of lagoon and seaward reefs. It is most common on the
windward seaward reef, up shallow where the waves break in the groove and spur systems.
Rarely is it calm enough in there to dive, so we usually see them on the lagoon side of the same
reef, where specimens have been washed across when their sponge prey gets ripped off the wall
by excessive surge.
Rusty nudibranch
Glossodoris rufomarginata
The name means “red-margined” but the color is really more brown. Like the last species, this
one lives mostly in the rough groove and spur system on the windward seaward reef, and
frequently gets washed across the reef when the surge breaks up the sponges they live on.
White’s nudibranch
Hypselodoris whitei
Only a few specimens of this species have been seen at Kwajalein, all in Halimeda patches on
the sandy lagoon slope.
Ornate nudibranch
Cadlinella ornatissima
This small species is usually found under rocks on shallow lagoon reefs.
Dendrodorid nudibranch
Dendrodoris albopurpura
This fairly large nudibranch is most often found under rocks on shallow lagoon reefs.
Tuberculose nudibranch
Dendrodoris tuberculosa
This highly variable, lumpy nudibranch is mostly found in patches of Halimeda algae on lagoon
reefs. It is fairly large, up to at least 100mm in length. Its skin secretes a toxic substance that
deters predators and is quite painful if it gets in your eyes.
Tuberculose nudibranch
Dendrodoris tuberculosa
This is another color form of the nudibranch seen in the previous scene.
Madrella nudibranch
Madrella ferruginosa
This unusual nudibranch is sporadically common in lagoon Halimeda patches, where it feeds on
the encrusting black bryozoan seen in the lower left quarter of the frame.
Notobryon nudibranch
Notobryon sp.
So far we have seen this species on only a few occasions, most of them at night in lagoon
Halimeda patches. It is currently being worked on to see if it is an undescribed species.
Throw-netting nudibranch
Melibe viridis
This flimsy, translucent nudibranch lives in lagoon algae patches and feeds using a throw net.
Actually, it expands out a frilled hood at the front of its body, “throwing” it around algae, closing
it down and using the frills to filter out any minute swimming shrimp and other food items,
which it delivers to its mouth. There are at least two other kinds of Melibe nudibranchs in these
waters, and all have the same method of feeding.
Orange-spotted seaslug
Chelidonura fulvipunctata
This variable seaslug is found in Halimeda patches on lagoon reefs.
Blue & orange streaked seaslug
Chelidonura hirudinina
This species is sporadically common in lagoon Halimeda patches. It seems to occasionally
congregate for breeding.
Pilsbry’s seaslug
These are occasionally found in sand on both lagoon and seaward reefs.
Philinopsis pilsbryi
Forskal’s seaslug
Pleurobranchus forskali
These variably-colored slugs are found sporadically in lagoon Halimeda patches. On one
occasion, they were found under rocks in large numbers on a small reef near Bigej, where they
were apparently breeding.
Forskal’s seaslug
This is another color form of the slug in the previous scene.
Pleurobranchus forskali
Thorny sea cucumber
Thelenota ananas
Sea cucumbers are occasionally confused with sea slugs. This is a small specimen of a common
large species that can be found throughout the atoll.
Imperial shrimp on sea cucumber
Periclimenes imperator
Occasionally, the sea cucumber seen in the previous scene and others may host a number of
hitchhiking commensals. On a few cucumbers, you might find a pair of these attractive small
shrimp. These shrimp may also live on large nudibranchs.
Imperial shrimp on sea cucumber
Periclimenes imperator
Here the shrimp has moved to the underside of the thorny sea cucumber. All the red dots are the
cucumber's tube feet.
Imperial shrimp on sea cucumber
Periclimenes imperator
As in some other shrimp, the male is usually much smaller than the female.
American shrimp on sea cucumber
Gnathophyllum americanum
Another shrimp that is occasionally riding on sea cucumbers is this little species, which is more
commonly found around sea anemones.
American shrimp on sea cucumber
Gnathophyllum americanum
The shrimp seen in the previous scene comes in a yellow form as well. This one is hiding on a
different sea cucumber, Holothuria hilla.
Eyed sea cucumber
One of the more attractively marked sea cucumbers is this species.
Bohadscia argus
Eyed sea cucumber juvenile
Bohadscia argus
This is a small juvenile of the sea cucumber in the previous scene. It is host to a commensal
worm, seen just slightly to the right of the middle of the cucumber’s side.
Orbicular crab on sea cucumber
Lissocarcinus orbicularis
Another hitchhiker on sea cucumbers is this small crab, in this scene on the underside of a thorny
sea cucumber (Thelenota ananas). A sea cucumber is basically a tube that pulls in sand at one
end (the mouth), processes it through the tube to digest out anything edible, and drops the
processed sand out the other end (the anus). These crabs live just inside either end of the sea
cucumber, sampling food items (or whatever) as the sand goes past. Occasionally, they emerge
and wander about on the cucumber’s body. Not a bad life, I guess, as long as you don't mind
where your dinner's been. The circles in the substrate are the retracted tube feet on the underside
of the sea cucumber.
Orbicular crab on sea cucumber
Lissocarcinus orbicularis
These crabs vary somewhat in color. Some are dark with white spots, while others more white
with dark spots.
Orbicular crab on sea cucumber
Lissocarcinus orbicularis
Notice how this one holds on by grabbing the skin of the sea cucumber.
Coral crab in branch coral
Trapezia sp.
Among the branches of corals live several kinds of coral crabs. Sometimes they get pretty
defensive and come out and pinch your finger if you bring it too close. This defensive behavior
may help protect the coral from predation by the crown-of-thorns starfish (Acanthaster planci).
A crown-of-thorns feeds on coral by crawling over it and extruding its stomach over the coral.
The coral tissue is digested in place and drawn into the star. However, if these little crabs start
pinching the star’s stomach as it extrudes it, it may drive the star away to find a less aggressive
coral.
Crab
These flattened, well camouflaged crabs can move fast if they want to.
Tarantula crab
Camposcia retusa
This is a master case of camouflage. It is virtually impossible to see this crab until it starts
moving. This species is also called one of the decorator crabs because it decorates its shell with
bits of algae, sponge, and anything else that might be around to help it blend in with its
surroundings.
Tarantula crab
Camposcia retusa
Here is another one with more sponge and tunicates in addition to the algae. Its long-legged walk
reminds me of a tarantula and the crab is about the same size.
Swimming crab
Charybdis sp.
Swimming crabs have flattened rear appendages that they can use to paddle themselves through
the water. Still, they spend most of their time on the bottom.
Green shrimp attacked by crab
This tiny green shrimp almost gets caught by a crab coming up from below. It's a dog eat dog
(crab eat shrimp?) world out there.
Tiny shrimp
This is another tiny shrimp that emerged from a clump of Halimeda algae.
Mantis shrimp in algae
Mantis shrimps, or stomatopods, are elongate crustaceans with anterior appendages that fold up
somewhat similar to those of a praying mantis, although the direction of the joint action is
opposite. They are able to work those joints very quickly, causing them to be able to strike out
with their appendage to stun, chop, or spear prey. Some stomatopods have clubs on the ends of
their appendages, others have sharp blades, and some have comb-like spines. This is a rather
small species, only about 60mm long.
White mantis shrimp
This is another small species that is currently unidentified.
Giant mantis shrimp
Lysiosquilla sp.
This large species is always seen at the mouth of its hole, where it watches what goes by with
those bizarre, independently moving eyes. More often you just see the hole, with the shrimp
retracted down inside. Looking down the hole, the sides of the tunnel are smooth and curve
slowly away out of sight. To keep the sand from collapsing, they must cement the walls with
mucus or some other stabilizer. This species is one with a sharp, comb-like anterior appendage,
which can be whipped out to skewer prey. You wouldn't want one to mistake your finger for
something edible.
Giant mantis shrimp eyes
Here is a close up of the eyes of the specimen in the previous scene.
Green mantis shrimp
Lysiosquilla sp.
Odontodactylus scyallarus
This large species is probably the gaudiest of the stomatopods. Rare throughout much of the
atoll, there is at least one place where we can sometimes see several, usually just their heads
looking out of burrows they build with rubble. This one was unusual in that it came out to swim
for us. These are good sized, this one at least 150mm in length.
Green mantis shrimp
This one moves out a rock that has fallen into its burrow.
Odontodactylus scyallarus
Green mantis shrimp eyes
Another one looking out of its burrow. Look at those strange eyes.
Odontodactylus scyallarus
Green mantis shrimp scrubs eyes
Odontodactylus scyallarus
This one uses some brush-like appendages to clean off its eyes. Must be like using a
handkerchief to wipe off a pair of glasses.
Shell blenny
Petroscirtes xestus
This blenny is usually found living in empty seashells on lagoon reefs. This one looks as though
it might be in an old wormhole.
Cleaner mimic
This blenny is also occupying an old empty worm or vermetid hole.
Triplefin
The identification of this tiny goby-like fish is uncertain.
Aspidontus sp.
Ucla xenogrammus?
Morrison’s dragonet
Synchiropus morrisoni
Dragonets are common bottom-dwelling fish on both lagoon and seaward reefs.
Dwarf goby
This small goby is usually seen on the ceilings of caves and overhangs.
Trimma sp.
Emperor changes color
Lethrinus sp.
This carnivorous emperor is able to change its color rapidly as it hunts for prey in a patch of
algae.
Humpback snappers
Lutjanus gibbus
A large school of humpback snappers swarms about a lagoon patch reef. Also passing through
are a few bigeye emperors (Monotaxis grandoculis) and a female whitespot parrotfish (Scarus
forsteni).
Multibar goatfish feeding
Parupeneus multifasciatus
A group of young goatfish feed on the surface of a rock. A few other wrasses and damsels join
in.
Bluegreen chromis
Chromis viridis
The fish school around above a branching Porites coral. The damsels are scared down to the
coral a couple of times.
Bluegreen chromis
Chromis viridis
Schooling over Pocillopora coral with a few bluestriped snappers (Lutjanus kasmira), goldlined
emperors (Gnathodentex aureolineatus), one black and white damsel (Dascyllus aruanus) and
lots of transparent cardinalfish.
Damsels and cardinalfish
This small reef surrounded by sand is home to many damsels and cardinalfish.
Pygmy sweepers
Parapriacanthus ransonneti
These sweepers resemble cardinalfish that are always on the move. They are sharing their hole in
the reef with a few yellow cardinals (Apogon luteus).
Pygmy sweepers
Sweepers never stop moving.
Parapriacanthus ransonneti
Yellow cardinalfish
Apogon luteus
These cardinals are on an isolated reef on a lagoon slope. They are hovering above a sea
anemone (Entacmaea quadricolor) and a juvenile emperor angelfish (Pomacanthus imperator) is
in the background.
Juvenile emperor angelfish
Pomacanthus imperator
Same as the previous scene but a different angle. Juvenile emperor angels tend to live around
isolated lagoon slope reefs. As they grow, they move to other reefs, many even crossing the
intertidal to reach the seaward reef.
Emperor angelfish
Pomacanthus imperator
This is a small individual that looks like it has only recently changed to its adult coloration.
Bicolor angelfish
Centropyge bicolor
This striking angelfish is found primarily on lagoon reefs and pinnacles. Rarely one might be
seen on the seaward reef. The larger one gets chased back to its area by a damsel near the end of
the scene.
Merten’s butterflyfish
Chaetodon mertensii
These can be found on a variety of lagoon and seaward reefs. They usually travel in pairs.
Ornate butterflyfish
Chaetodon ornatissimus
This species, also usually found in pairs, feeds exclusively on live coral. Like other obligate coral
feeders, it is not a species suitable for the home aquarium.
Vagabond butterflyfish
This butterfly is found mostly on lagoon reefs and pinnacles.
Chaetodon vagabundus
Forceps butterflyfish
Forcipiger flavissimus
These butterflies are found on seaward, lagoon, and pinnacle reefs. It can be distinguished from
the very similar longnose butterfly by its mouth, which is shaped like a little set of forceps or
tweezers at the very end. The longnose butterfly has little more than a hole in the end of its long
snout. There are also some minor color differences.
Longnose butterflyfish
Forcipiger longirostris
Very similar to the previous forceps butterflyfish, but usually has a longer snout and has some
black speckling in the white patch beneath the black head.
Tomato clownfish
Amphiprion melanopus
This anemonefish is most often found in this kind of anemone (Entacmaea quadricolor). Further,
it is usually in the smaller, colonial form of the anemone. Anemones of this form are usually
clustered, often between branches of coral, and may cover several square meters of reef. Larger
specimens of the anemone are usually solitary and occupied by threestripe clowns (Amphiprion
tricinctus).
Tomato clownfish
Amphiprion melanopus
When the tomato clown is younger, they have one or two stripes behind the most anterior one,
but all but the first fade away as the fish grows. Even when young, though, it is much more red
than the other clownfish species from this area. This one is in a solitary brown anemone
(Entacmaea quadricolor).
Threestripe clownfish
Amphiprion tricinctus
This species of anemonefish is most often found in the anemone Entacmaea quadricolor. When
in this anemone, the fish is mostly orange in the front and black toward the rear. The distribution
of Amphiprion tricinctus seems to be restricted to the Marshall Islands. It has not been reported
elsewhere.
Black threestripe clownfish
Amphiprion tricinctus
When this clownfish is in a carpet anemone (Stichodactyla mertensii), the orange disappears and
the entire animal is black with white bands.
Threestripe clownfish
Amphiprion tricinctus
Young individuals of the threestripe clownfish are usually in Haddon’s anemone (Stichodactyla
haddoni) or, like here, in the sand anemone (Heteractis aurora). Often the young ones are all
orange to orange brown with white bands.
Threestripe clownfish
Amphiprion tricinctus
This young threestripe clownfish was nearly all black and in an anemone that we have rarely
seen here. The anemone is Heteractis malu, and we have recognized for certain only two
individuals, one near Kwaj and one past Nell, both in the lagoon.
Twostripe clownfish
Amphiprion chrysopterus
Another regular inhabitant of carpet anemones (Stichodactyla mertensii) is the twostripe clown.
These are the largest of the four species of clownfish in the Marshalls and are the most
aggressive. These fish will occasionally come out and nip at divers to drive them away from their
anemones.
Brown zoanthids
Zoanthids are somewhat similar in appearance to both soft corals and sea anemones, but they do
not exactly fit into either group. This brown one was on a small reef on a lagoon slope. A couple
of yellow cardinalfish (Apogon luteus) come into the scene near the end.
Green zoanthids
These zoanthids were also found on an isolated lagoon reef.
White zoanthids
More lagoon dwellers.
Green zoanthids
The green discs of this species were quite bright. Some species of zoanthids are highly toxic.
Organ pipe coral
Tubipora musica
This coral is rather drab in life, but when washed in on the beach and exposed to the sun, the
skeleton of closely packed tubes connected by small flat plates turns bright red. The living coral
polyps are seen at the top of the colony.
Organ pipe coral
Tubipora musica
This is looking down on a living colony of organ pipe coral with some of the polyps retracted.
From the top, the interesting organ pipe structure is not evident.
Soft coral
Pachyclavularia violacea
This coral is somewhat related to the organ pipe coral above but lacks a hard skeleton.
Grasping soft coral
Xenia sp.
This soft coral spends most of its time “grasping” with the tentacles of its polyps. Presumably
this helps it catch planktonic food.
Razor coral
Fungia sp.
These razor coral disks are not attached to the bottom as adults and most species, like this one,
consist of a single coral polyp. The mouth is in the depression in the center of the top. Because
they are unattached, some fish will flip them over in search of crabs, shrimp, or other prey hiding
beneath. Consequently, in areas where these are common, many of them are upside down. They
seem to survive like this for some time, but since they also require sunlight for their symbiotic
zooxanthellae algae, they probably do better upright. On some dives, I spend a lot of time
flipping these things back over.
Razor coral in cave
Fungia sp.
Sometimes, if a razor coral falls into a dark cave, it may expand out its tissue to take advantage
of all the sunlight they can. Occasionally, they can also use this “ballooning” of their tissue to
actually flip upright if they have been turned over.
Ziczac cowry
Palmadusta ziczac
This is one of the rarest cowries at Kwajalein, although in areas farther west, such as the
Solomon Islands, they are quite common. We have seen shells on shallow lagoon reefs, in lagoon
Halimeda patches, and on the seaward reef.
Mole cowry
Talparia talpa
The mole cowry is relatively large. The shell has a black base and yellow or yellow and brownbanded dorsum. The mantle that covers it, however, is black densely speckled with small green
spots and covered with rounded bumps. It can be found throughout the atoll, but this specimen
was under a rock on a shallow lagoon reef near North Loi.
Mole cowry
Talparia talpa
This mole cowry’s shell is completely hidden by the green-spotted mantle. It was on a lagoon
reef north of Bigej.
Tiger cowry
Cypraea tigris
The tiger cowry is big and bulbous, the largest specimens at Kwaj exceeding 100mm (about four
inches) in length. They get larger in Hawaii, and one more than 150mm in length is known from
there. Unlike most cowries, it frequently does not hide during the day, so it is one of the few
species somewhat susceptible to over-collection. This one was in a lagoon Halimeda patch.
Manta ray
Manta birostris
Manta rays can be seen both in the lagoon and on the seaward side. One of the best places is
along the lagoon side of the east reef, where they come in over the reef to be worked over by
cleaner wrasses. This one has an accompanying sharksucker (Echeneis naucrates).
Whitetip shark
A whitetip cruises the edge of a lagoon reef.
Triaenodon obesus
Whitetip shark
Whitetips are common in all parts of the atoll.
Triaenodon obesus
Gray reef shark
A gray reef shark passes above the camera.
Carcharhinus amblyrhynchos
Gray reef shark
Carcharhinus amblyrhynchos
A gray reef comes to investigate the photographer in a heavily coral-covered area.
Gray reef shark
Carcharhinus amblyrhynchos
Credits
This DVD was filmed and edited by Scott and Jeanette Johnson. It was shot with a couple of
different Sony DV and (for a few scenes) Hi8 video cameras in an underwater housing by Light
& Motion Industries. Video scenes were captured to a Windows XP PC and edited using Adobe
Premiere.
Music written and performed by Cori Ashley and Ed Franks from their CDs Forest Dreams,
Naturecise 1 and Naturecise 2.