Biotopes of Japan | Stiphodon percnopterygionus

Marcelo Fernandez Biotope, Biotopes of Japan 1 Comment

The first time I saw a photo of a Stiphodon sp. I felt a sensation of observing a masterpiece of art, I have always been amazed (and still feel the same today), those colours of the males combined with the characteristic iridescent lines near the mouth make them special and unique.

This “drawing” made them practically perfect. Then researching and looking for information, over time, I understood a little more about their biology, I now knew their real size, how they always tried to be on top of the rocks to control everything visually from there. Of course, the characteristics of its biotope, a remote place with a unique beauty, always with streams and many other things that I learned from a habitat so far away for those of us who live in South America.

Stiphodon percnopterygionus | ©

The name of this singular species is derived from the combination of the Greek word stifos, which means “swarm” and odon, which means “toothed”, in reference to the numerous clenched teeth on the upper lip of the species and after the word perknos, which means dark color, and from the Greek word pterygion, the diminutive for fin or wing, this refers to the small angular dorsal fin of black color.

This small omnivorous goby gets its food from the algae attached to the rocks along with some small betonic animals that inhabit them and in the substrate of its biotope, it is generally found in the flow of gentle currents in the upper and middle basins of the rivers of Shizuoka prefecture, Kochi prefecture, Miyazaki prefecture, Tanego island, Yakushima island, Kuchino Nagarabu Island, Ryukyu Islands and Ogasawara Islands in Japan and also in Taiwan, Guam and Palau . (Watson & Chen 1998)

In males there are two color variations, Orange (which we managed to photograph in their biotope) and blue. Females are brownish in color and have two vertical black bands that run through the body from the mouth to the beginning of the tail fin. The dual coloration of males found in S. percnopterygionus is not known in any other Stiphodon species. The males of both color phases found throughout their range include transitional coloration, and the variation is attributed to size and not geographic distribution. (Nanyô-bôzuhaze, Akihito et al., 1984, 1988).

In Stiphodon species, only the life history of Stiphodon percnopterygionus Watson & Chen, 1998, from the Ryukyu Archipelago has been studied. This species has the following characteristics: it is amphidromous, that is to say that during its life it moves between bodies of fresh and salty water since this goby produces small piriform eggs that are deposited on the lower surface of the stones in freshwater streams (Yamasaki and Tachihara, 2006) then the newly hatched larvae, which are small (1.2–1.3 mm) and poorly developed, migrate or are carried downstream to the sea shortly after hatching at sunset, where they develop as pelagic larvae for 2.5–5 months. At 13-14 mm standard length (SL), the larvae migrate to freshwater streams for increased growth and reproduction (Yamasaki et al., 2007; Maeda and Tachihara, 2010). The life histories of the other Stiphodon species are expected to be similar to those of S. percnopterygionus. (Yamasaki et al. 2007) and Maeda et al. (2012a) suggested that members of this genus may colonize distant islands through dispersal of pelagic larvae, but poor distribution information and unstable taxonomy make such a discussion challenging. Reliable knowledge of the distribution of each Stiphodon species is invaluable in understanding the actual situation of larval dispersal and in discussing the population structure and speciation history of this genus.

Affinities: Stiphodon percnopterygionus most closely resembles S. rutilaureus Watson, 1996 from Papua New Guinea, Solomon Islands and Vanuatu, and an undescribed species from Halmahera, Indonesia. All three species have 10 segmented rays on the second dorsal fin, 14 pectoral rays, and poorly developed skin sensory papillae, but more closely resemble S. rutilaureus as both species have the first triangular dorsal fin. The Halmahera species has the first rounded dorsal fin with a fourth filamentous dorsal spine. The males of the three species can be separated by coloration.

After doing a tour of Japan, visiting of course some biotopes, what for me was the most anticipated moment of this trip arrived, I was finally going to witness the habitat of the Stiphodon pernopterygionus for the first time.

After taking a plane from Osaka to Ishigaki, one of the Ryu Kyu Islands of Okinawa prefecture, I had to go to the port of it and go to Iriomote Island, the latter is of a very particular beauty, an island 90% Virgin with very little population, located a short distance from Taiwan and tourists only come to see its waterfalls, kayak and some more daring trekking circuits. At the port I got on a Ferry that usually have regular services for tourists and inhabitants of Iriomote and after an hour, I was already in Taketomi Ohara, a small town very close to the mouth of the Nakama River. The river he wanted to visit, although not in its estuary.

In the first photo you can see one of the small islands of the Yaeyama district, from the Okinawa Prefcture that are on the way to Iriomote, at the mouth of the Nakama River towards the sea there are two sculptures of the panther “Iriomote Yamaneko“ (Prionailurus bengalensis iriomotensis ) of Iriomote Island and which is the icon of the Iriomote Ishigaki National Park. Finally a Lion or Fu Dog (also known as lions of the Buddha) protecting the Island, these sculptures originate from China and are all over the Taeyama Islands since they are very close to the latter country and Taiwan.

Unfortunately I had to break one of my most precious expedition rules, number one, the most important, always going out with a local guide. This I could not fulfil although I tried until the last moment I did not succeed and for several reasons, two of the main ones were: the great problem of the language, it is very difficult to communicate with the people there since nobody or practically almost nobody speaks English, much less Spanish, and although I was able to handle a cell phone translator application throughout Japan in these Islands, it was very difficult for me since many locals use a different Japanese to communicate or a dialect within the same language, another issue was that the few guides who know the island very well had already assigned their programs to take tourists to these previously named activities far from these points that they wanted to observe.

Returning, on my arrival, I was lucky that an old man took me with his truck to the mouth of the Nakama River, which at that point of the river becomes very wide, allowing the formation of Mangrove forests.

The beauty of the mouth of the Nakama River, to think that many larvae of these freshwater gobies enter here. (Watson & Chen)

On the other side of the bridge, with your back to the mouth, you can clearly see the mountains where these waters come down, forming the habitat we are looking for.

I was still lucky and I found a couple of inhabitants of the Island who worked with tourists taking them to cross the river in their barges, thanks to them and to the translator of the cell phone plus some gestures and the occasional word of in English they showed me how I could do to get to an old trekking path that was now used by a biology university to classify species from this dense jungle and that would help me a few kilometers to enter the jungle and advance faster, everything was simple in theory (like always), the path started in an old cemetery, would it be a sign?

I started to walk with a backpack with all the photography equipment, provisions, water and some shelter since it is always cold in the jungle, even if we are in the tropics.

At the end of the short road from the small town of six streets is this cemetery, then there is nothing more, just the jungle with its mountains.

Once I entered the road, already in the darkness of the jungle, the first thing that caught my attention was a small land turtle native to the island and which is protected. With his yellow face, really very pretty and of considerable speed.

A sequence of two different specimens of this turtle, one in a clearing and one in the jungle hidden in a hollow log. (Cuora flavomarginata).

I kept walking and always tried to listen to some waterfall or strong current sound and what led me to the first stream, where I spotted my first góbido of the day (Thinogobius sp.) With about three species of crabs and some prawns on a very thin water that ran from the top of the mountain. Luckily I was able to photograph the fish with my submersible camera and take parameters that are the main thing of these expeditions, so that we can always give our fish the closest thing to its place of origin. These were:

Photo of the first research point.

Time: 10:12
pH: 7.65
Conductivity: 195uS
Temperature: 25 ° C

After taking a break and taking many photos and footage of the place, I continued on my way, always along the Nakama River but in the upper area, since it is impossible to walk several meters along the river and the water there is brackish, for therefore it was not what he was looking for at the time. After an hour walking in the jungle, I already came across small wild boars, calves of a species apparently from there and that appears as part of the protected animals, these small and distant relatives of the pigs were beautiful and very scary, there were several encounters and in none of them did he give me time to photograph them, it was not the reason for the expedition either, but I should have used a longer range lens, but at one point walking in silence in an area where my footsteps did not make much noise, I look up and I meet an adult female boar, it was only two seconds but for me it was like 2 hours, she looked at me and I only thought where the male was going to come out protecting her and if she would think that she wanted to do any harm to her cubs, luckily he got scared and quickly got lost in the undergrowth, it was the longest two seconds of my life together with the encounter with a bothrops sp. in Jandiatuba, Amazonas, but it is another story.

I kept walking about 3 km more through the jungle and my ears heard water, in a totally inaccessible place, it was there, but how could I enter having to go down a practically impossible ledge, because I tried and when I was almost passing I could see the stream and it was extremely small, I was wrong with its great sound and it was not worth wearing the body and risking it being alone in the middle of the mountain and without a guide !. I decided to keep looking and walk about 2 or 3 more kilometers, luckily after crossing more Boar cubs my ears again heard water but this time it was an intense sound and

every time I got closer the waterfall was heard louder and louder , the humidity in the environment was one hundred percent and the muzgos were everywhere, when I managed to climb a wall of rocks my eyes saw a paradise in the form of a stream, a natural beauty that could be the cover of any Outdoor magazine or Poster for a spa. The place is unique and enthralls the view. It is that same photo that heads this article. As soon as I looked at that postcard I thought … “-Here you have to be Stiphodon! “

Always knowing that Iriomote Island is a national park and therefore could not touch any living being, I had to adapt to these rules that seem excellent to me since it is the only way to conserve and care for our environment.

He had already studied what his biotope was like, the characteristics of the water, the type of place where he had to be and thus be able to decipher in which sector of the stream he could find it.

I would have to look for an area in the stream with the current necessary to coincide with the biotope of the Stiphodon, neither so strong nor so weak, I could see that this beautiful góbido seeks the area with space where to appreciate its territory with the current passing moderately from a rock for the area it inhabits. The meeting was magical and can be seen exactly in the video below , luckily, the moment where I see him for the first time face to face in his own biotope , a feeling of enormous happiness, he was very tired, with little time before nightfall and he has to leave that paradise, a totally virgin place.

The parameters of this place were:

Time: 17:03
pH: 7:59
Conductivity: 135uS
Temperature: 26 ° C

Exact place where the Stiphodon percnopterygionus was. (Observe the “Mild Current”) .

There he is. Dominating all its territory from above. A beauty .

Another view from another angle.

Here moving to another rock.

Two of a females that were in that territory, with some other unidentified gobies. The female is very pretty also being very different in coloration. I have seen several females together also that unfortunately the underwater photos did not go well.

Other inhabitants of the biotope:

This could be a Rhinogobius sp. MO (Yoshinobori goby).

These are one of many Gobies known as “longsnout” or longnose since the upper lip protrudes forward, this one is perhaps an Awaous melanocephalus (Bleeker, 1849). And in the background you can see how some Kuhlia sp. that did not resemble the K. rupesris (Lacepede, 1802) that are cited for this island (I saw them up to about 20 cms approximately).

Regarding these gobies in the previous photo, the Awaous sp, (Kazuumi Hosoya) generally inhabit the upper and middle basins of rivers, the flow of the current is smooth and you can see where there is mud or sand, when they are surprised they can be buried in stream sediments or sand. The breeding season is from June to November and the eggs are deposited on the roof under some rounded stone.

Maturation begins when the body is approximately 4cm. Long, but only when he reaches 7 cm is he sexually mature.

It feeds on benthic animals found in the substrate sand and sediments on the stones.

These freshwater shrimp measure approximately 20 cms.

Also in the biotope there are crabs of various sizes and species. This one here measures about 10 cm.!

Finally, with the satisfaction of having been lucky enough to appreciate this small 3.8 cm gem in its environment and the other fish that inhabit it, those large prawns that reached up to about 20 cm (really huge) in this stream that came down from the mountain in the middle of a virgin jungle plagued with wild boars, turtles, mangroves, incredible birds I realized because the

Okinawa prefecture cared so much for this little paradise being so small (289 km2) and so fragile. I could see that a university had used part of some trekking path for the classification of vegetation, which gave me the idea that the Japanese government or its universities are classifying and studying such a beautiful ecosystem.

Although we could say that the expedition ended here, this was not the case. How does a fanatic biotope explorer do to leave such a rich and natural place and not continue exploring? Well, it’s impossible!

Blinded by curiosity, I wondered… -How will the encounter of this stream with the Nakama River be? And there I went …

Going down between waterfalls and rocks, but knowing that later I would have to go back and climb all over again, I arrived at the small mouth of this nameless stream, after seeing incredible landscapes, with the intense deafening sound of cicadas at their peak, I see the Muddy Nakama River, the sector that corresponded to the lowest part of the Nakama, the banks of it are very muddy from the sediment that comes down from several mountain streams through the jungle. At last I had arrived where I wanted and finally I could appreciate another habitat that I had in mind and that I did not want to miss for anything in the world.

The biotope of the Mud Skippers!

Thanks to my family for putting up with this crazy fish obsesion and to Iuki and husband for all their cordiality.


· Kazuumi Hosoya Ryo Uchiyama. “Peces de agua dulce” edición japonesa. Yamagata Handy picture book.

· Ronald E.Watson and I-Shiung Chen “Freshwater gobies of the genus Stiphodon from Japan and Taiwan” (Teleostei: Gobiidae: Sicydiini). Aqua, Journal of Ichthyology and Aquatic Bio.

· Harumi Sakai and Morizumi Nakamura “Two New Species of Freshwater Gobies” (Gobiidae: Sicydiaphiinae) from Ishigaki Island,Japan. (Received December 18,1978)

· Tony H.M. “First records of several sicydiine gobies” (Gobiidae: Sicydiinae) from mainland China. Nip Asia Ecological Consultants Limited, 127 Commercial Centre, Palm Springs, Yuen Long, N.T., Hong Kong, China.

· Yuichi Kano1, Shin Nishida2 & Jun Nakajima3. “Waterfalls drive parallel evolution in a freshwater goby”. 1Graduate School of Engineering, Kyushu University, Fukuoka, Japan 2Graduate School of Social and Cultural Studies, Kyushu University, Fukuoka, Japan 3Fukuoka Institute of Health and Environmental Sciences, Dazaifu, Fukuoka, Japan.

· Lord Clara, Watanabe Shun, Kelth Phillippe. “Population structure of the Asian amphidromous Sicyliinae goby, Stiphodon percnopterygionus with comments on larval dispersal in the northwest Pacific Ocean”.

· “Amparu guide book” Ishigaki Nagura.

· Katsunori TACHIHARA, K ohei NAKAO, Keishi TOKUNAGA, Y uko TSUHAKO, Mikumi TAKADA and Tumid SHIMOSE. “Ichthyofauna in Mangrove Estuaries of the Okinawa, Miyako, Ishigaki and Iriomote Islands during August from 2000 to 2002”

· Ken Maeda*, Takahiko MuKai & Katsunori Tachihara “A new species of amphidromous goby, Stiphodon alcedo, from the Ryukyu Archipelago (Gobiidae: Sicydiinae)”.


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