Kushimoto, the southernmost city of Japan’s mainland, is home to the world’s northernmost coral reefs (see Photos 1 & 2, and Map)
Photo 1: Coral reef at Kushimoto Marine Park, Wakayama Prefecture. Most of the corals visible in this photograph are species of Acropora.
Photo 2: An ‘oriental butterflyfish’ Chaetodon auripes, feeding on plate coral (Acropora sp). Many species of butterflyfish (Family Chaetodontidae) specialize on corals, especially corals in the genus Acropora.
Although its latitude is the same as Santa Catalina Island, California (33o28’ North), Kushimoto lies directly in the path of the Kuroshio Current (see Map).
The Kuroshio Current brings warm water from the tropics to the coast of Japan, similar to the Gulf Stream of the Atlantic Ocean. Kushimoto’s sea temperatures average 27oC (80.6oF) in August, compared to 20.5oC (68.9 oF) in Santa Catalina Island. Along with the warm water, the Kuroshio Current transports the planktonic larvae of corals and tropical fish to Kushimoto (see Photo 3 & Video 1). Dr. Kotera and his colleagues at the Kushimoto Marine Park Aquarium have documented more than 1,500 species of fish in and around Kushimoto (Photo 4). Thus, I went to Kushimoto to observe and photograph these fish (see Photo 5). I also wanted to compare these fish to those I was familiar with from Santa Catalina Island, Rocky Point (northern Sea of Cortez) and the islands of French Polynesia and Hawaii.
Photo 3a: Larval fish spend a few weeks to a few months as plankton before settling onto shallow reefs. These juvenile butterflyfish, Chaetodon speculum (mirror butteflyfish - yellow with black spot, left side) and C. trifascialis (chevron butteflyfish – right side) were seen in 6 feet of water at Kushimoto Dive Park this February (2012). Their small size indicates they recently settled out of the plankton. In the upper left corner is a southern orange-lined cardinalfish, Apogon properuptus (Family Apogonidae).
Photo 3b: Many fish have distinct juvenile phases, such as this painted sweetlips juvenile (Family Haemulidae, Diagramma pictum).
Photo 3c: Adult painted sweetlips, Diagramma pictum.
Photo 4: Dr. Kotera and myself at the Kushimoto Dive Park Aquarium, August 2011. Behind us is the Underwater Observation Tower. Visitors can descend 5 m (15 feet) below sea level and observe fish without getting wet.
Photo 5: The Bizen dive site at Kushimoto is famous for it large and easy to approach sea bass (Family Serranidae): here a large tomato hind (Cephalopholis sonnerati) is surrounded by shoals of pygmy sweepers, Parapriacanthus ransonneti (Family Pempheridae, above and left of the bass) and spotnape cardinalfish, Apogon notatus (below and above right).
My first dives in Kushimoto were made in June and July of 2009, which were also my first dives in mainland Japan (six SCUBA dives and snorkeling). I identified 89 species of fish from 42 families and 72 genera*. Of these, 63 species were new to me, as were six of the families and 22 of the genera (see Photos 6-14). The familiar species were fishes I had encountered either in French Polynesia, Hawaii, or both (e.g. Photo 15). None of these species occur in California no Rocky Point.
Photo 6: A pair of Chaetodon nippon, Japanese butterflyfish (summer 2009). This species and C. auripes were new to me in 2009, but were the most common species of butterflyfish seen that summer and this year.
Photo 7: The third most common butterflyfish seen in 2009 was Chaetodon kleinii, (Klein’s butterflyfish, aka sunburst butterflyfish). Typical of many butterflyfish, they occur in pairs and are likely monogamous. This species is closely related to the Tahitian butterflyfish (C. trichrous), the subject of my recent research. Although common in 2009, I did not see them in August 2011 nor February 2012. Also in this picture are several ‘sea goldies’, Pseudanthias squamipinnis (Family Serranidae), another common fish of Kushimoto.
Photo 8a: The Family Labridae (wrasses) is the second most speciose of marine fish families. They are mostly tropical, and many species undergo protogynous sex change, reproducing first as females, and changing later into males. Often, this change in sex includes a change in color pattern, from an initial phase (IP) to a terminal phase (TP). In addition, juveniles may express a different color pattern prior to maturation. These changes in color have led to multiple names for members of the same species. Female Halichoeres poecilopterus (IP, aka Parajulis poecilepterus) a common wrasse here, and elsewhere in Japan.
Photo 8b: Male H. poecilopterus (TP). Note the black spot posterior to the pectoral fin. The males of many wrasse species have distinctive coloring either near their pectoral fin or on the fin itself.
Photo 9: This wrasse, Pseudolabrus sieboldi, or its congener, P. eoethinus (Figure 23c), were seen on nearly every dive in Kushimoto and elsewhere in Japan both in 2009 and this year; a ‘new’ genus in my experience.
Photo 10: A male Choerodon azurio (scarbreast tuskfin, Labridae). This large wrasse was found on deeper dives in 2009 and this year; another ‘new’ genus.
Photos 11a-11c are representatives of three ‘new’ families of fish. Each of these families is relatively small, with 18, 6 and 11 species (respectively).
Photo 11a: Family Cheilodactylidae (morwongs), Goniistius zebra. This species and its congener, G. zonatus, were seen at most of the dive sites in Kushimoto. I later saw G. zonatus in Hawaii.
Photo 11b: Family Oplegnathidae, knifejaws, Oplegnathus punctatus, juvenile. This species and O. fasciatus have distinct juvenile color patterns, whereas the adults are more similar to each other. Both species were occasionally seen in Kushimoto and elsewhere along the Pacific coast of Japan.
Photo 11c: This fish was seen only in Kushimoto, and only in 2009; Family Pentacerotidae (armorheads) Evistias acutirostris.
Photo 12: Sharp-nosed puffers, or tobies, are small members of the puffer family, Tetraodontidae. This colorful species, Canthigaster coronata, the crowned puffer, was found on the deeper, western dive sites of Kushimoto. It’s congener, C. rivulata, was seen at all the dive sites around Kushimoto, as well as other sites on the Pacific coast and the Sea of Japan.
Photo 14a: Scorpionfishes (Family Scorpaenidae) lie on the bottom, waiting for small prey to approach their mouths, so they can be rapidly sucked up. They must match their surroundings to avoid detection with the use of color pattern, cirri (head appendages) and behavior (act like a rock). To protect themselves, they contain some of the most potent venom of any fish in their spines. Here is Scorpaenopsis neglecta, in rubble.
Photo 14b: Scorpaenopsis cirrhosa, on a turf-covered rock. My dive guide lifted up this scorpionfish with a probe so that the fish would display its fins and cirri. If done gently, the fish will remain motionless. I caution against handling any wild animal, especially a poison-spined scorpionfish.
Photo 15: These yellow goatfish (Mullidae, Mulloidichthys vanicolensis) have come to be ‘cleaned’ by the wrasse, Labroides dimidiatus. Note the head-down pose and faded colors of the central goatfish. Any parasites or wounds on the fish will be more visible to the cleaner wrasse. The wrasse will eat the parasites and any necrotic tissue around a wound. The wrasse gains a meal and the goatfish is rid of parasites, a classic example of mutualistic symbiosis. Both species are broadly distributed throughout the Indo-Pacific, and were common in Kushimoto.
This year I made another series of dives in August 2011 and in February 2012 to identify additional species, and to compare the fish community between summer and winter. Including my dives in 2009, my list of Kushimoto fish now includes 167 species, in 52 families and 107 genera. Only one new family was added to this list (Coryphaenidae) when I finally saw a mahi mahi (Coryphaena hippurus) while making my safety stop at the end of a dive (camera turned off). An additional 16 new genera and 57 new species were added to my 2009 identifications (totals: 7 new families, 38 new genera and 120 new species).
Two species were seen on every dive this year: neon damselfish, Pomacentrus coelestis, (Pomacentridae, Photo 16) and scalpel sawtails, Prionurus scalprum (Acanthuridae, Photo 17). Almost as common were yellowtail clownfish (Amphiprion clarkii, Pomacentridae, Photo 18), oriental butterflyfish (Photo 2), spottedtail morwongs, Goniistius zonatus (Cheilodactylidae, Photo 19), whitesaddle goatfish, Parupeneus ciliatus (Mullidae, Photo 20), brown-lined puffers, Canthigaster rivulata (Tetraodontidae, Photo 21), Japanese parrotfish, Calotomus japonicus, (Scaridae, Photo 22) and four species of wrasses (Labridae): cupid wrasses, Thalassoma cupido , cutribbon wrasses, Stethojulis interrupta , red naped wrasses Pseudolabrus eoethinus , and cleaner wrasses, Labroides dimidiatus (see Photos 23 & 15).
Photo 16: Neon damselfish, Pomacentrus coelestis, the most common fish seen in Kushimoto. Damselfish (Family Pomacentridae) are related to wrasses and another speciose family of fish.
Photo 17: Scalpel sawtails, Prionurus scalprum (Family Acanthuridae, surgenofishes) were seen at all dive sites and every dive made in Kushimoto.
Photo 18: Yellowtail clownfish, Amphiprion clarkii (Family Pomacentridae) with anemone. Anemones were abundant throughout the reefs of Kushimoto, and so were clownfish - seen on over 90% of my dives.
Photo 19: Spottedtail morwongs, Goniistius zonatus (Family Cheilodactylidae) were not abundant, but were common, seen on over 90% of my dives. Its congener was also seen frequently (60% of dives, Photo 11a).
Photo 20: A whitesaddle goatfish, Parupeneus ciliatus (Family Mullidae) along the wall at Bizen dive site. These goatfish were seen on over 80% of dives. In the background are many Nagasaki damselfish, Pomacentrus nagasakiensis (Pomacentridae), a common planktivore in Kushimoto (60% of dives).
Photo 21: Brown-lined puffer, Canthigaster rivulata (Family Tetraodontidae), the most common pufferfish in Kushimoto, and also seen elsewhere in Japan.
Photo 22: Japanese parrotfish, Calotomus japonicus, (Family Scaridae) were seen on over 90% of dives. Parrotfish are close relatives of wrasses, and like wrasses, most change sex. Parrotfish are named for their ‘beaks’ of fused teeth, used to scrape algae from coral and rocks. Members of the genus Calotomus, however, have unfused teeth. A related species, the loosetooth parrotfish, Nicholsina denticulata, is the only parrotfish I have seen in Rocky Point, Mexico, at the northern end of the Sea of Cortez.
Photo 23a: These wrasses (Family Labridae) were seen on over 90% of all dives. Cupid wrasse, Thalassoma cupido (upper right, with neon damselfish, Pomacentrus coelestis, in coral).
Photo 23b: Cutribbon wrasse, Stethojulis interrupta.
Photo 23c: Red naped wrasse Pseudolabrus eoethinus. Its congener was seen frequently in Kushimoto, but was more common elsewhere in Japan (Figure 9).
Wrasses (Family Labridae) are the second largest family of marine fish, colorful and easily seen while diving. Wrasses were the most speciose group seen in Kushimoto: 27 species in 14 genera; 19 of these species and 8 genera were new (Photo 24). Similarly, damselfish (Pomacentridae, 13 species in seven genera) and butterflyfish (Chaetodontidae; 10 species in three genera) were well represented. These three families are broadly distributed in the tropics, but rare in temperate zones. Santa Catalina Island, for example, is inhabited by only three wrasses, two damselfish (including the state marine fish, garibaldi, Hypsypops rubicundus) and one butterflyfish.
Photo 24: Three species of wrasse and a goatfish (largest fish), Glass Wall/Good Wrasse dive site, Kushimoto. Although I made only three dives at this site, I recorded 7 species and 3 genera of wrasses here that were new to me. The large green-bodied fish on the left is a pale-barred coris, Coris dorsomacula, the smaller green-bodied fish on the left is a smalltail wrasse, Pseudojuloides cerasinus, the others are threadfin wrasses, Cirrhilabrus temminckii, except for the largest fish – a bicolor goatfish, Parupeneus barberinoides.
Gobies (Family Gobiidae) are the most speciose family of marine fishes. However, gobies include the smallest of all fish, many hide in caves and rocks, and they tend not to be seen on a general reef survey (Photo 25). Similarly, blennies are relatively common, yet small and overlooked (but see Photo 26). Other species are rare, and highly cryptic, such as this frogfish seen in Kushimoto (Photo 27). Finding small cryptic fish takes much time, or the help of an experienced dive guide. Fortunately, Aki Tanimai helped me find some of these fish.
Photo 25a: Sagamia geneionema gobie.
Photo 25b: Bathygobius fuscus gopie.
Photo 26: A tube blenny, Neoclinus bryope, Family Chaenopsidae.
Photo 27: A painted frogfish, Antennarius pictus, Family Antennariidae. If you have trouble finding the fish, look for its eye, below and right of center; the black spot of the eye is surrounded by a distinctive ring of protective structures.
Many of the more common species are limited to the northwest Pacific: Japan, Korea and the East China Sea (e.g. oriental butterflyfish, Japanese butterflyfish, Nagasaki damselfish) while others are broadly distributed. The following four species come from small families. Two common fishes with limited distributions in the Pacific were the threadsail filefish, Stephanolepis cirrihifer (Family Monacanthidae, Photo 28) and the largescale blackfish, Girella punctata (Family Girellidae, Photo 29). However, both of these fishes were found elsewhere in Japan. By comparison, two broadly distributed tropical species common in Kushimoto were the Moorish Idol, Zanclus cornutus (Family Zanclidae, Photo 30) and eyestripe surgeonfish, Acanthurus dussumieri (Family Acanthuridae, Photo 31). Neither of these fishes were seen elsewhere in Japan.
Photo 28: A threadsail filefish, Stephanolepis cirrihifer (Family Monacanthidae), common in Kushimoto and elsewhere in Japan, but not broadly distributed in the tropical Pacific.
Photo 30: Moorish Idols, Zanclus cornutus (Family Zanclidae) are broadly distributed across the tropical Indo-Pacific. They were seen on 75% of dives in Kushimoto, but not elsewhere in Japan.
Photo 31: Eyestripe surgeonfish, Acanthurus dussumieri (Family Acanthuridae), has a similar distribution to its relative, the Moorish Idol.
Despite the Kuroshio Current, the waters around Kushimoto cool off significantly in the winter, 15-17 oC (59-62.6 oF). Some of the tropical fish that arrive as plankton in the spring and summer, cannot survive the lower winter temperatures. Whereas I identified an average of 41.2 species (range: 35-48) per dive in the summer, I found an average of 35 species (range: 20-43) per dive in the winter. Five of the species seen in February, but not in the summer, were single juveniles (e.g. the butterflyfish in Photo 3a), recently arrived on the Kuroshio Current. They may not live long in the cold water. However, Dr. Kotera has seen more species survive the winter over the last few years, which he attributes to global warming.
The Shionomisaki Peninsula, the southernmost extension of Kushimoto, traps warm water on its western side, while the current is diverted somewhat offshore on the eastern side of the peninsula (see Photo 32). I made boat dives and beach dives on each side of the peninsula. Temperatures were 2-5 oC (3.6-9.0 oF) warmer on the western side. Species diversity was similar in the summer, but in the winter there were fewer species on the colder, eastern side of the peninsula.
Photo 32: A map of Kushimoto and the Shionomisaki Peninsula. Most of my dives were made on the western side of the lighthouse, in the marine parks (shaded areas). I also made boat dives just east of the lighthouse (near the red dot) and from the beach near the bridge.
The reefs of Kushimoto are referred to as ‘the Mecca of diving in Japan’ for good reason. The conditions were generally good for diving, visibility ranged from 5-30 m (16-100’) and the water was generally warm, although a bit colder than expected in winter. Moreover, the diverse fishes and other marine organisms provide many subjects of study. Marina and Ami enjoyed snorkeling with me and Marina sketched clownfish while I searched for new species. Even non-divers can watch fish from the Underwater Observation Tower (Photos 4 & 33). Much thanks to Dr. Kotera of the Kushimoto Marine Park Aquarium for sharing his knowledge of the local fishes, and Akihiko Tanimai (Photo 34) owner and Divemaster of Dive Station for his expertise in bringing me to all these fish. Attached (below) is a complete list of fish identified. Here are a few more pictures of fish (Photos 35-41 & Video 2) and two cephalopods from Kushimoto (Photo 42 & Video 3).
Photo 33: Marina viewing the Underwater Observation Tower, Kushimoto Marine Park Aquarium. We were later told to visit the tower from inside, only.
Photo 34: Akihiko Tanimai, owner and operator of Kushimoto Diving School, Dive Station. Tanimai-san is an expert diver and photographer, and he knows the local flora and fauna.
Photo 35: Japanese pygmy angelfish, Centropyge interruptus (Pomacanthidae), the most common angelfish seen at Kushimoto.
Photo 36: Two blacktip groupers, Epinephelus fasciatus (Serranidae).
Photo 37: Thornback cowfish, Lactoria fornasini (Ostraciidae). Cowfish are members of the boxfish family; their bodies protected by a series of plates. Cowfishes have the addition of horns on their head and projecting posteriorly.
Photo 38: A pair of juvenile threespot damselfish, Dascyllus trimaculatus (Pomacentridae). Juveniles of this species settle onto anemones and remain there for protection until they reach a larger size.
Photo 39: This yellow hawkfish, Cirrhitichthys aureus (Cirrhitidae) is one of three species in this genus seen at Kushimoto. The genus and these species were ‘new’.
Photo 40: Lionfish, Pterois volitans (Scorpaenidae).
Photo 41: Grass puffer, Takifugu niphobles (Tetraodontidae), a type of fugu, a poisonous fish served in specialty restaurants in Japan.
Photo 42: This cuttlefish, either Sepia esculenta or S. erostrata (Family Sepiidae, Class Cephalopoda, Phylum Mollusca) was watching me take pictures of fish in February (see Photo 38).
Fish of Kushimoto, Complete List
* The scientific names used here were based on the field guide ‘Fishes of Japan’ by Okamura and Amaoka, 1997, Yama-Eki Publishers, Tokyo (in Japanese), modified by the advice of Dr. Kotera and his working list of fish in and around Kushimoto. Other scientific names (synonyms) are in use for some of these species; the common names vary locally.