Welcome photo, Eleotris oxycephala, provided by Dr. Shibukawa
What's new
An new ecology topics posted on 7 August 2022
Site opening on 28 July 2022
Tell Me Again
Here follows information on a common fish, the goby. Is this a goby!! This site is full of information on a species of fish that you may not be so familiar with. The goby is also famous as a species that the former Emperor Akihito (the Emperor Emeritus) of Japan has studied. Professor Imamura, who has prepared this goby content, has given a lecture on fish phylogeny at a research meeting attended by the Emperor Emeritus himself.
His speech to the Linnean Society, mentioned in "The Emperor and Goby Research," was published in Nature. It is worth reading.
Sha in Japanese Kanji is a word for waterside. In summer, when there are many opportunities to go to the water's edge, it would be fun to use the knowledge you have learned at FoM and look out for gobies. You may be rewarded with new discoveries.
FoM Editorial
28 July 2022 posted
Photo on the back: Odontobutis obscura (Odontobtidae) (photo by Dr. K. Shibukawa).
What Are Gobies?
Gobies are fish belonging to the order Gobiiformes. They show high species diversity, more than 2000 species in 8 families and 321 genera are found around the world, according to Nelson et al. (2016). Many species of goby are distributed in marine waters, while about 200 species are known to occur in fresh water. Their habitats are also variable, rivers (including mountain streams), lakes and marshes in freshwater habitats, to sandy and muddy seabottom, rocky coasts, coral reefs, and mangrove forests in saltwater habitats. Gobies also inhabit brackish water. Some gobies are associated with snapping shrimps. They are morphologically characterized as having a fusiform body in general, two dorsal fins (in many species), the pelvic fin below the pectoral fin, those on both sides fused to form a sucking disk (in many species), absence of the swimbladder usually, the gill membrane fused with the isthmus and absence of the pyloric caeca. Gobies range in size from 1 cm to 60 cm in body length, but most species are under 10 cm.
As mentioned above, gobies show high species diversity and are adapted to various habitats, Japanese people who enjoy fishing as a hobby are familiar with species such as Yellowfin Goby (Acanthogobius flavimanus) which are easy to catch. Gobies are also well-known in Japan as His Majesty the Emperor Emeritus studies them. In this section, FoM provides background on several aspects of gobies. Please enjoy.
Photos are kindly provided by Dr. Hiroshi Senou (Kanagawa Prefectural Museum of Natural History) and Dr. Koichi Shibukawa (Museum of Natural and Environmental History, Shizuoka).
IMAMURA Hisashi・Faculty of Fisheries Sciences, Hokkaido University・Professor / the Fisheries Science Center, the Hokkaido University Museum・Director
Figure Gobiid Amblyeleotris japonica and snapping shrimp Alpheus bellulus (photo from Kanagawa Prefectural Museum of Natural History, taken by M. Uchino)
28 July 2022 posted
An Encouragement of Studying Goby: Is It Really So Difficult to Identify/Classify Gobies?
"It is difficult to identify/classify gobies." It's a phrase I often heard when I was still an undergraduate student, more than a quarter of a century ago. It may be more appropriate to be replaced with the phrase "It is unclear for me." I always felt it was a little strange; because, for me, the phrase seemed to be a prejudice taking merely on by a person with no experience in goby research (non-gobiologist).
Gobies, including many smaller species, certainly require some familiarity and technique during observation. In many cases a microscope is needed for observing details and measuring each part of the body using a caliper. For accurate examination of the cephalic sensory canals and papillae, which are notable as taxonomic characteristics, the help of a staining solution such as cyanin is required. The scales are easy to rub off, and the fins are delicate. In the preserved specimens with fewer spreading fins, researchers sometimes struggle even to count the fin rays.
The large number of species also contributes to the perception of difficulty. In those days, it was not as easy to get information as it is now, due to the lack of a fully developed internet. For researchers not familiar with gobies, it must have been problematic just to identify the infra-familial taxa.
However, working actually on gobies would reveal that the negative mind is just a prejudice. You will find that the time and effort of observation is not so different from other small fish. The fact that they are the small-sized and are rich in species number is also not a big problem in taxonomy works, compared to, say, insects. If you have the opportunity to gather enough information, the remnant effort needed is just to be used to it. However, if the amount of effort caused people to lose interest, they often ‘gave up’. The perception that it was too difficult would lead a self-fulfilling, unsuitable prophecy.
As time goes by, the situation has changed considerably compared to those days. If you open your computer or smartphone, you can find not only scientific articles from all years and countries, but also a wide variety of information and useful tools, such as various databases that gather this knowledge in one place, automatic translation sites for many languages, and daily tweets and vivid images by fish fanciers all over the world. Of course, you have to sort the wheat from the chaff, but in any case, the amount of information and the ease of accessing information have both improved significantly. The numerous images found on the internet show not only common species but also fascinating, presumably unnamed ones. It is like a dream world, more than that we could imagine in the old days.
When I talk to students and/or young researchers, a generation strong at collecting and using such information, I always feel that they think goby taxonomy is ‘interesting’ rather than ‘difficult’. The phase has undoubtedly changed. I look forward to how goby studies will develop in the future after the opening of Goby content in FoM.
SHIBUKAWA Koichi・Museum of Natural and Environmental History, Shizuoka
28 July 2022 posted
Species Diversity of Gobies
Classification of organisms is not always universally accepted and may differ between different authorities. In this section, species diversity of gobies is presented based on characteristics of each of the seven families recognized as shown in Shibukawa (2021).
Rhyacichthyidae (loach gobies): Two genera and three species of Rhyacichthyidae are known around the world and one (Rhyacichthys aspro) occurs in Japan. Loach gobies inhabit fast-flowing mountain streams and are found in the Indo-Australian Archipelago, New Caledonia, Philippines, China and Solomon Islands. They are morphologically characterized as having features such as the head depressed and tail compressed, mouth inferior, pelvic fins on both sides widely separated and lateral line developed on the body.
Odontobutidae (freshwater sleepers): The family Odontobutidae includes 6 genera and 21 species around the world, and two genera and three species occur in Japan. Odontobutids live in freshwater, and are also found in Korea, China, Vietnam and Russia. Freshwater sleepers are characterized as having features such as six branchiostegal rays, pelvic fins on both sides widely separated and presence or absence of lateral line on the body.
Milyeringidae (blind cave gobies): This family includes only two species of Milyeringa in Western Australia and three species of Typhleotris in Madagascar. Because blind cave gobies inhabit caves and sinkholes, they lack eyes and four species (except Milyeringa mararybe) also lack any pigments on the body. They also have some common morphological features, such as an elongated and shovel-like snout and a well-developed system of sensory papillae on the head.
Eleotridae (spinycheek sleepers): Spinycheek sleepers usually inhabit brackish and freshwater, and are found in temperate, tropical and subtropical areas. Eleotridae includes 28 genera and more than 130 species around the world, and 8 genera and 16 species occur in Japan. Of these, five species of the genus Xenisthmus are classified into the family Xenisthmidae in “Fishes of Japan with pictorial keys to the species, third edition” (Akihito et al., 2013). Spinycheek sleepers are characterized as having features such as the pelvic fins usually separated, absence of lateral line on the body and segmented caudal fin rays usually 15. The largest eleotrid is Dormitator maculatus which is 60 cm in length.
Butiidae (butid sleeper): Butid sleepers inhabit freshwater and estuaries in tropical Indo-Pacific areas and West Africa. This family includes 10 genera and 46 species around the world, and three genera and three species in Japan. They are characterized as having features such as six branchiostegal rays, pelvic fins separated, absence of lateral line on the body and segmented caudal fin rays usually 17.
Thalasseleotrididae (ocean sleepers): The family Thalasseleotrididae is a newly described group, established in 2012. Ocean sleepers occur in marine waters and are found in the western Pacific from temperate Australia to New Zealand. Only two species in Thalasseleotris and a single species in Grahamicthys are known at present. This family is defined by a single character, membrane connecting the hyoid arch to the first ceratobranchial broad.。
Gobiidae (gobies): The term Gobiidae used here includes the families Kraemeriidae, Microdesmidae, Ptereleotridae and Schindleriidae recognized in Akihito et al. (2013). This family has the highest diversity in Gobiiformes, containing about 275 genera and more than 1950 species. They are known from all over the world except for polar regions and occur in both freshwater and saltwater. In Japan, there are about 110 genera and more than 650 species (including some unidentified ones). Gobiids have characteristics such as well-developed system of sensory papillae on the head, five branchiostegal rays, pelvic fins fused to form a disk and absence of lateral line on the body.
IMAMURA Hisashi・Faculty of Fisheries Sciences, Hokkaido University・Professor / the Fisheries Science Center, the Hokkaido University Museum・Director
Figure Rhyacichthys aspro (Gobiidae) (photo from Kanagawa Prefectural Museum of Natural History, taken by N. Kumazawa).
References
Akihoto, Sakamoto K., Ikeda Y., Aizawa M. (2013) Gobioidei. Pages 1347–1608, 2109–2211 in Nakabo T. ed. Fishes of Japan with pictorial keys to the species, third ed. Tokai University, Hadano (in Japanese).
Gill A. C., Mooi R. D. (2012) Thalasseleotrididae, a new family of marine gobioid fishes from New Zealand and temperate Australia, with a revised definition of its sister taxon, the Gobiidae (Telesotei: Acanthomorpha). Zootaxa 3266: 41–52.
Larson H. K., Foster R., Humphreys W. F., Stevens M. I. (2013) A new species of the blind cave gudgeon Milyeringa (Pisces: Gobioidei, Eleotridae) from Barrow Island, Western Australia, with redescription of M. veritas Whitley. Zootaxa 3616: 135–150.
Shibukawa K. (2021) Classification of gobies. Pages 22–23 in Senou H. ed. A photograph guide to the gobioid fishes of Japan. Heibonsha, Tokyo (in Japanese).
Sparks J. S., Chakrabarty P. (2012) Revision of the endemic Malagasy cavefish genus Typhleotris (Teleostei: Gobiiformes: Milyeringidae), with discussion of its phylogenetic placement and description of a new species. Am. Mus. Novitates 2012: 1–28.
Nelson J. S., Grande T. C., Wilson M. V. H. (2016) Fishes of the world, fifth edition. Wiley, New Jersey.
28 July 2022 posted
Yellowfin Goby-The Best-Known Representative of Japanese Gobies
Many Japanese would have enjoyed catching gobies from breakwaters in their childhood. Because gobies have a large mouth and are readily attracted to bait, they are easy to catch, even for small children. Although there are several goby species which can be caught in coastal regions, the best-known representative of gobies in Japan is the Yellowfin Goby (Acanthogobius flavimanus). In this section, this common goby is described.
Yellowfin Goby is a member of the family Gobiidae. It ranges from southern Hokkaido to Tanega-shima Island in Japan. It is also known in the Korean Peninsula, China and Russian Primorskii. Although it has also been recorded in Sydney and California, it is considered that larvae of Yellowfin Goby were taken into ships with ballast water and transported to these regions by them. Yellowfin Goby are found on sandy and muddy seabottoms in inner bays shallower than 5 m and estuaries, they also enter freshwater regions. It is somewhat large in size, usually about 20 cm in total length, and occasionally reaches 30 cm. It has morphological characteristics such as the body covered with ctenoid scales, and cheek and opercular regions with cycloid scales, the head lacking barbels and skinny flaps, eyes small and interorbit narrow, the width of latter about less than 1/2 of the former, the pelvic fins on both sides fused and forming a disk with notches anteriorly and posteriorly, the body pale yellowish brown with scattered dark spots, and dorsal and caudal fins with rows formed by black spots. Its spawning season is midwinter to early spring. Female gobies spawn in sandy and muddy burrows. Young individuals are found in river estuaries, but as they grow, they move to deeper coastal regions in late autumn to winter. Many individuals are mature and spawn about one year after hatching, after which they die.
Yellowfin Goby is edible. It comes in season from autumn to winter. There are several cooking methods but the most common way to cook it is as tempura. Goby tempura in the Tokyo style is very famous in Japan. It can also be prepared fried, grilled or eaten raw as sashimi.
Writing about it makes me want to eat it. This species is also found in my hometown Hakodate, Hokkaido. I will go to fishing for goby at the weekend and try to make tempura.
IMAMURA Hisashi・Faculty of Fisheries Sciences, Hokkaido University・Professor / the Fisheries Science Center, the Hokkaido University Museum・Director
Figure Yellowfin Goby (Acanthogobius flavimanus) (photo from Kanagawa Prefectural Museum of Natural History, taken by H. Uchino).
References
Akihoto, Sakamoto K., Ikeda Y., Aizawa M. (2013) Gobioidei. Pages 1347–1608, 2109–2211 in Nakabo T. ed. Fishes of Japan with pictorial keys to the species, third ed. Tokai University, Hadano (in Japanese).
Shibukawa K. (1998) Yellowfin Goby. Pages 164–165 in Nakabo T, Mochizuki K eds. The encyclopaedia of animals in Japan. 6 Fishes. Heibonsha, Tokyo (in Japanese).
28 July 2022 posted
His Majesty the Emperor Emeritus’ Research on Gobies
His Majesty the Emperor Emeritus of Japan is well-known in his home country for his research into goby taxonomy. It should be stressed this is not a hobby but actually his research is at a serious professional level. This can be easily found from his research results. For example, the website of Imperial Household Agency shows 30 papers he published in scientific journals which were issued from the Ichthyological Society of Japan, a Japanese academic society for ichthyology. The most recent paper was published in May 2021, in which two new gobiids, Callogobius albipunctatus and Callogobius dorsomaculatus, were described (Akihito and Ikeda, 2021). In addition, this website shows four papers which appeared in other scientific publications. Of these, a paper published in 1896 was also presented by himself in an oral presentation in English in “The Second International Conference on Indo-Pacific Fishes” held in Tokyo in 1985. Moreover, he has published manuscripts for sections on gobies in “The Fishes of the Japanese Archipelago” and “Fishes of Japan with Pictorial Keys to the Species”, both of which included all known Japanese fish species at that time.
He is also a member of the Ichthyological Society of Japan, which was mentioned above. Accordingly, he sometimes attends the annual meeting of the society. Recently, he attended an annual meeting held in Tokyo in 2018 and listened to oral presentations on gobies. He is an Australian Museum Honorary Associate and Honorary Member of the Zoological Society of London, for example. On the latter Society, he addressed a keynote speech in English on the celebration of the 300th anniversary of the birth of Carl von Linné by the Society in 2007.
For his research activity, his name has been used in the scientific names of three goby species. The first is Platygobiopsis akihito, described as a new genus and new species based on specimens collected from Flores, Indonesia (Springer and Randall, 1992). The second is Exyrias akihito. This species was newly described based on specimens from Iriomote Island, Philippines, Indonesia, Papua New Guinea and the Great Barrier Reef of Australia, the western Pacific (Allen and Randall, 2005). The third is Priolepis akihitoi, which was newly described on the basis of specimens collected from Shizuoka Prefecture, Japan (Hoese and Larson, 2010).
IMAMURA Hisashi・Faculty of Fisheries Sciences, Hokkaido University・Professor / the Fisheries Science Center, the Hokkaido University Museum・Director
Figure Priolepis akihitoi (photo from Kanagawa Prefectural Museum of Natural History, taken by H. Uchino).
References
Allen G. R., Randall J. E. (2005) Exyrias akihito, a new species of coral-reef goby (Gobiidae) from the western Pacific. Raffles Bull. Zool. 53: 231–235.
Hoese D. F., Larson H. K. (2010) Description of two new species of the genus Priolepis from the Indo-Pacific with redescription of Priolepis profunda and Priolepis psygmophilia. Ichthyol. Res. 57: 373–388.
Springer V. G., Randall J. E. (1992) Platygobiopsis akihito, new genus and species of gobiid fish from Flores, Indonesia. Japan J. Ichthyol. 38: 349–355.
28 July 2022 posted
Diversity of Ecological Aspects of the Gobies
When I said "I am researching on the gobies," many of the Japanese, who are not so knowledgeable about fishes, can only think of the yellowfin goby (Acanthogobius flavimanus), which is famous to be cooked as tempura. Those who have read this series of articles already know that there are numerous other goby species. The gobies show not only extreme species diversity, but also remarkable diversity in ecological aspects. This ecologically rich diversification, and also the natural conditions that made it possible, appears to have been a major driving force for the current explosive speciation of gobies.
Gobies can be found almost anywhere in the world in waters where fish live (except for polar regions, extremely deep seas, and open oceans far from land). Many of them are found in marine waters, although there are also some land-locked species and species that move between the sea and freshwater rivers. The last case is further divided into some migration patterns, e.g., those that go up the river for spawning (anadromous migration) and those that go back and forth between the sea and the river at a certain growth stage regardless of spawning (amphidromous migration).
Gobies are typically benthic, and, in many cases, they are usually hidden under objects such as boulders. The other examples of habit/habitat include: hovering above the nest hole; swimming freely and, when they are disturbed, sneaking quickly into the bottom sand; lying down on the flat sandy bottom, and sometimes burying the body in the sand shallowly; dwelling in sponges and between branches of reef-building corals; being in symbiotic relationships with snapping shrimps; dwelling in deep seas on the seabed; in soft mud in/around estuaries; hidden among the roots in mangrove forests; usually found only in the underflow of the river; in the rapids in the upper reaches of the river, clinging to the rocks using strong sucking-disc-like pelvic fins. It is particularly surprising that some gobies (mudskippers) hop and creep on exposed mud flat, as if they are escaping from the water.
In the eelgoby genus Luciogobius, typically dwelling in the interstices of the intertidal gravel beaches, it is not unusual that some species are found sympatrically. However, if you investigate carefully, you may find a kind of rough microhabitat segregation; there are minor differences in the environmental conditions (e.g., grain size of gravel, the degree of influence of fresh water, and the strength of the waves) that each species prefers. In Japan, where diverse gravel environments are found along the coast, a rash of the discovery of undescribed species of this group has been occurring in recent years, and our recognition of species diversity of this group is being significantly updated.
There are many cases where previously unknown species are discovered in environments that have not been paid attention to in the past; this is a case not only in the eelgobies, but also in many other gobies. Diversity in the ecological aspects of the gobies which have succeeded in dwelling in many kinds of water environments, is undoubtedly rich; it may take a long time before we know the whole picture of their diversity.
SHIBUKAWA Koichi・Museum of Natural and Environmental History, Shizuoka
Figure Luciogobius yubai (Gobiidae) (photographed by Dr. K. Shibukawa), dwelling among interstices of gravel on intertidal shore
7 August 2022 posted
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