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 Chironephthya sp. This is a closer shot of the previous scene. Soft coral 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 Nembrotha kubaryana Stretching from rock outcrop to algae. 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 Phyllodiscus semoni The close view of this anemone shows the curling tentacles. 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 Spirobranchus giganteus Orange and white specimen. Spiral-gilled tubeworm Spirobranchus giganteus Yellow with a brown core. Spiral-gilled tubeworm Spirobranchus giganteus Mostly greenish gray with white tips to the gill feathers and a pinkish core. Spiral-gilled tubeworm Spirobranchus giganteus White at the base, turning mostly maroon toward the spiral tree tops. Spiral-gilled tubeworm Spirobranchus giganteus Mostly brownish maroon with white mottling. 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 Spirobranchus giganteus Combination of maroon, yellow and white. 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 Paraluteres prionurus The are most common on the seaward reef. 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 Gymnothorax javanicus Closer view of the head. It opens and closes its mouth as it breathes. 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 Epitonium sp. Where you see one, there will often be more. 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 Tridacna maxima Blue green with black stippling. Maxima clam Tridacna maxima Darker purple blue spotted with black. 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 Tridacna maxima Light and dark brown. Maxima clam Tridacna maxima Interesting combination of green, brown, and blue. Maxima clam Tridacna maxima Dark green with some black. Maxima clam Tridacna maxima Green, light brown and black. Embedded in living Porites rus coral. 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 Anampses meleagrides This fast moving wrasse is usually hard to get very close to. Juvenile dragon wrasse 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 Caesio teres Looking up toward the surface to see the fish pass above. 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 Pterocaesio tile These couldn’t decide which way to go. 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 Acropora danai? Common in shallow on seaward reefs. 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 Pachyseris rugosa Looks like a rugged mountain range shot from above. 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 Lobophyllia sp. This may be another species of stalk coral. 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 Distichopora sp. A closer view of the same spot. 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 Timoides agassizi? This small pinkish jellyfish is mostly rare here. 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 reef-damaging, 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 Tridacna squamosa This one is yellow and tan on dark brown. 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 Tridacna squamosa This one is mostly brown with yellow spots and black streaks. 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 Tridacna gigas A relatively small one on a shallow reef. 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 Tridacna gigas This one has some especially bright green color. 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 Allogalathea elegans Closer shot of the last scene. 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 Halicampus mataafe? This frondose little pipefish is difficult to see in its algae habitat. 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 Scorpaena sp.? This is likely a different color form of the species in the previous scene. 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 Octopus cyanea More of the same from the previous scene. 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 Priacanthus hamrur An especially bright red one. 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 Labropsis alleni We see these mostly on deep lagoon reefs and the slopes of lagoon pinnacles. 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 Platax orbicularis The batfish are often quite curious and will come right up to a diver. Orbicular batfish Platax orbicularis As they get larger, their banding fades somewhat. 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 Platax orbicularis A very friendly one comes in to take a close look at the camera lens. 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 Pterocaesio marri With a few neon fusiliers (Pterocaesio tile). 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 Caesio teres This school swims over a large table on a pinnacle slope. Blue & yellow fusiliers Caesio teres Again, these are swimming over a large table on a pinnacle slope. 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 Triaenodon obesus This one passes by on top of a midlagoon pinnacle. 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 Carcharhinus amblyrhynchos Comes in for a close pass. 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 Aetobatus narinari Accompanied by a sharksucker (Echeneis naucrates). 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 Brissus sp.? This one is about halfway dug in again, and is still digging. 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 Casmaria ponderosa A third bonnet shell, probably also a male, joins the fray. 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 Stichodactyla haddoni This is an unusual pink color for the anemone. 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 Antennarius pictus Closer view. 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 Antennarius commerson? In a head on view, it is hard to recognize it as a fish. 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 Callechelys marmorata Closer view. 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 Pseudoceros jebborum This one crawled out of Halimeda algae on a lagoon sandy reef. 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 Chlamys irregularis? With the thick blue coat on this shell, it is hard to be sure of the species. Irregular pecten Chlamys irregularis? This one seems to have extremely long tentacles. 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 Tridacna gigas We have also been watching this one grow over the past few years. 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 Heteractis magnifica This one is all balled up, showing off its purple stalk. 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 Halgerda albocristata This nudibranch lives under rocks on shallow lagoon reefs. 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 Sclerodoris tuberculata This red species is easy to mistake for a clump of red sponge. 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 Philinopsis pilsbryi These are occasionally found in sand on both lagoon and seaward reefs. 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 Pleurobranchus forskali This is another color form of the slug in the previous scene. 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 Bohadscia argus One of the more attractively marked sea cucumbers is this species. 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 Lysiosquilla sp. Here is a close up of the eyes of the specimen in the previous scene. Green mantis shrimp 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 Odontodactylus scyallarus This one moves out a rock that has fallen into its burrow. Green mantis shrimp eyes Odontodactylus scyallarus Another one looking out of its burrow. Look at those strange eyes. 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 Aspidontus sp. This blenny is also occupying an old empty worm or vermetid hole. Triplefin Ucla xenogrammus? The identification of this tiny goby-like fish is uncertain. Morrison’s dragonet Synchiropus morrisoni Dragonets are common bottom-dwelling fish on both lagoon and seaward reefs. Dwarf goby Trimma sp. This small goby is usually seen on the ceilings of caves and overhangs. 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 Parapriacanthus ransonneti Sweepers never stop moving. 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 Chaetodon vagabundus This butterfly is found mostly on lagoon reefs and pinnacles.

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 brown-banded 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 Triaenodon obesus A whitetip cruises the edge of a lagoon reef. Whitetip shark Triaenodon obesus Whitetips are common in all parts of the atoll. Gray reef shark Carcharhinus amblyrhynchos A gray reef shark passes above the camera. 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.