Papers Published in Japanese Journal of Ichthyology

Vol. 64, No. 1

April 25, 2017

CONTENTS
Original Papers
Comparison of monitoring methods for reed belt ichthyofauna in a eutrophic lake,
central Honshu, Japan
Kouki Kanou, Seiji Usui, Yuta Kawashima and Ken-ichi Yokoi
Re-examination of the native mitotype within wild populations of Japanese medaka(Oryzias latipes) in the Kanto region, Japan
Yuka Iguchi, Ryohei Nakao, Keisuke Takata and Tadao Kitagawa
Assessment of recreational fishing impact on the Biwa salmon resource based on
redd abundance at ten Lake Biwa inlet streams in 2015
Masanori Oda and Taiga Yodo
Microhabitat use by the endangered Itasenpara bitterling Acheilognathus
longipinnis (Cyprinidae) during the spawning season in the Moo River, Toyama,Japan
Masaki Nishio, Tomonori Kawamoto, Ryosuke Kawakami, Yasuyuki Hata,
Kaneaki Edo and Yuji Yamazaki
First specimen-based records of the Blackcheek Moray Gymnothorax breedeni from
Yonaguni-jima island, JapanKeita Koeda and Yuichi Akita
First Japanese record for a species of Pseudoscopelus (Acanthopterygii:Chiasmodontidae) lacking discrete photophoresFumihito Tashiro
Distribution of Anguilla japonica and A. marmorata in the Nansei Islands, Japan,and their habitat segregation based on local names
Yuichi Kano, Tomomi Yamashita, Wataru Tanaka, Akihiko Koyama andKazuki Kanno

Notes
A rare snailfish, Liparis bikunin, collected from Iwate, Japan
Yoshiaki Kai and Tsutomu Noda
An early specimen of Silurus lithophilus (Siluriformes: Siluridae) found in theNatural History Museum, London
Yusuke Hibino

Original Papers
Japanese Journal of Ichthyology
Vol. 64, No. 1, pp. 1–10

Comparison of monitoring methods for reed belt ichthyofauna in a eutrophic lake,
central Honshu, JapanKouki Kanou, Seiji Usui, Yuta Kawashima and Ken-ichi Yokoi
Abstract

Reed belts in temperate lakes support large numbers of fishes and provide

nurseries for many species, including some of endangered status or commercialimportance.

Although monitoring of such assemblages is important for ecological andfisheries assessments in many lakes in Japan, little information exists on appropriate
sampling gear for a better representation of fish species richness and composition in reed
belts. An evaluation of comparative efficiencies of different sampling methods formonitoring fish assemblages, based on six commonly used gear types [electrofishing (EF),minnow trap (MT), hand net (HN), casting net (CN), seine net (SN) and fyke net (FN)],
was conducted in lentic reed belts in a eutrophic lake, Kitaura, Ibaraki Prefecture, central
Japan, in June and August 2015. A total of 3,060 individuals, representing 11 families
and 26 species, were collected during the study period. The mean number of species per
replicate was significantly greater for FN, SN and CN than EF, MT and HN in eachmonth. More than 96% of the total species recorded throughout the study period werecollected by a combination of FN and CN. Furthermore, the species composition of theassemblages sampled by FN, SN and CN differed from that by EF, MT and HN, due tothe low catch efficiency of the latter. These results suggested that use of multiple gear
types, including FN and CN, represents a more efficient method for monitoring lentic
reed belt ichthyofauna.
(Corresponding author: Kouki Kanou, Center for Water Environment Studies, IbarakiUniversity,1375Ohu,kouki.kanou.sci@vc.ibaraki.ac.jp)

Itako,Ibaraki

311–2402,

Japan;

e-mail:Japanese Journal of Ichthyology
Vol. 64, No. 1, pp. 11–18

Re-examination of the native mitotype within wild populations of Japanese medaka(Oryzias latipes) in the Kanto region, Japan
Yuka Iguchi, Ryohei Nakao, Keisuke Takata and Tadao Kitagawa
Abstract

The current genetic disturbance in wild populations of Japanese medaka(Oryzias latipes species complex) has resulted from artificial introductions of non-nativepopulations and the commercial orange-red body color medaka variety (‘himedaka’).
Because the mitochondorial cytochrome b (cytb) “mitotype B1a” sensu Takehana et al.
(2003) is native to the eastern area around the Seto-Inland Sea (ESIS), as well asoccurring in himedaka, it had been believed that the mitotype B1a detected in the Kanto
region (eastern Japan) had resulted from artificial introduction from ESIS or throughhimedaka. This study, based on sequencing and RFLP analyses of the mitochondrial
hyper-polymorphic gene (ND2) in 99 O. latipes and 9 himedaka individuals, revealed
three additional haplotype groups (I, II and III) in the mitotype B1a. The major haplotype
group (Group I) apparently represents an artificial introduction, originally from ESIS orhimedaka. However, Group II seemed to be native to the Kanto region, to which it waslimited, since it was genetically divergent from the other groups. In addition, group III
was found to belong not to mitotype B1a but to another mitotype, the ambiguous RFLP
banding patterns found in the cytb analysis of the two mitotypes seemingly having led tothe former misconception. To avoid such misunderstanding, more accurate analyses, suchas sequencing or RFLP analysis of the ND2 gene as undertaken here, are required. Suchshould provide important new information for the conservation of genetic divergence inthe Kanto region.
(Corresponding author: Yuka Iguchi, Graduate School of Agriculture, Kindai
University, 3327–204 Nakamachi, Nara 631–8505, Japan; e-mail: iguchi.yk@gmail.com

or 1644680006w@nara.kindai.ac.jp)

Japanese Journal of Ichthyology
Vol. 64, No. 1, pp. 19–24

Assessment of recreational fishing impact on the Biwa salmon resource based on
redd abundance at ten Lake Biwa inlet streams in 2015
Masanori Oda and Taiga Yodo
Abstract

Biwa salmon, an endemic species and important fishery resource in LakeBiwa, migrate upstream from the lake in inlet streams during the spawning season.
Monitoring the number of spawning redds in such inlet streams can provide anassessment of the Biwa salmon population, similar population assessments having been
conducted for Bull trout (North America) and Sakhalin taimen/Masu salmon (Hokkaido,Japan).
Numbers of recreational fishermen targeting Biwa salmon began to increase around2006, becoming especially significant over the past four years. However, the potential
negative impact of such on the Biwa salmon resource is a concern. To assess the current
impact of fishing on Biwa salmon, spawning fish abundance and total redd counts of thelatter in ten Lake Biwa inlet streams during 2015 were compared with the results of aprevious study conducted in 2008, when recreational fishing was practiced on a smallerscale. Although spawning varied in each stream, the total redd count was comparable(1,066 in 2008 vs. 1,159 in 2015), indicating little impact on Biwa salmon resources dueto the recent increase in recreational fishing pressure. Comparisons of the body sizes ofmature fish showed no significant difference in average body size between 2009 and2015, a further indication of relatively low fishing impact. It was concluded, therefore,that the increase in recreational fishing has had little effect on the Biwa salmon
populations, likely due to the Shiga Prefecture initiatives to introduce early regulation ofrecreational fishing, as well as the common practice of most recreational fishermen topractice “catch and release”.
(Corresponding author: Masanori Oda, Tottori Prefectural Fisheries Experimental
Station, 107, Takenouchidanchi, Sakaiminato, Tottori 684–0046, Japan; e-mail:malma@sj8.so-net.ne.jp)

Japanese Journal of Ichthyology
Vol. 64, No. 1, pp. 25–30

Microhabitat use by the endangered Itasenpara bitterling Acheilognathus
longipinnis (Cyprinidae) during the spawning season in the Moo River, Toyama,Japan
Masaki Nishio, Tomonori Kawamoto, Ryosuke Kawakami, Yasuyuki Hata, Kaneaki Edo
and Yuji Yamazaki
Abstract

The Itasenpara bitterling Acheilognathus longipinnis is a small Japanese

cyprinid fish distributed on plains in the Toyama, Noubi and Osaka regions. Because
populations of the bitterling have been declining, the species has been recognized as“threatened” in the 2016 IUCN Red List and included as a critically endangered species
in the Red List of Threatened Fishes, compiled by the Ministry of Environment of Japan.
Because an understanding of the reproductive ecology of the species, especially spawning
habitat, is essential for future conservation of Itasenpara bitterling, observations wereconducted during the spawning season in the Moo River (Himi City, Toyama Prefecture,Japan), so as to clarify the utilisation of host mussels and determine the appropriate
microhabitat for spawning. Many reproductive groups were found in both lotic and lenticenvironments. Whereas spawning individuals often selected microhabitats of water depth
200–300 mm and current velocity <25 mm/s, non-reproductive groups were found onlyin the lentic environment, where both school formation and feeding behaviour wereobserved. Feeding occurred mainly in microhabitats of water depth 500 mm and current
velocity <25 mm/s. Thus, the observations indicated that Itasenpara bitterling in the Moo

River require shallow and deeper water microhabitats as spawning and feeding grounds,respectively.
(Corresponding author: Masaki Nishio, The Board of Education in Himi City, 1060
Kurakawa, Himi, Toyama 935–8686, Japan; e-mail: masaki.nishio@city.himi.lg.jp)

Japanese Journal of Ichthyology
Vol. 64, No. 1, pp. 31–35

First specimen-based records of the Blackcheek Moray Gymnothorax breedeni from
Yonaguni-jima island, JapanKeita Koeda and Yuichi Akita
Abstract The genus Gymnothorax Bloch, 1795, a highly speciose group belonging to
the family Muraenidae, currently comprises 126 valid species from tropical to temperateareas. Most of the 37 species already reported from Japanese waters are distributed insouthern Japan, the Ryukyu Archipelago and the Ogasawara Islands. The genus ischaracterized by its tubular anterior nostril, located anteriorly on the snout tip, and almost
equal tail and preanal lengths. Three specimens (534.0–920.0 mm total length) of theBlackcheek Moray Gymnothorax breedeni were collected concurrently in 7 m depth off
Yonaguni-jima island, southern Ryukyu Archipelago, Japan. The species has previously
been recorded from the tropical Indo-Pacific from eastern Africa to French Polynesia.
The collected specimens were characterized by the following combination of characters:
body moderate; anus slightly before middle of body; posterior nostril in upper position;
single teeth row on jaws; teeth absent on vomer; black patch extending as a prominentslash to a point just behind corner of mouth; gill opening in a black spot. Although thespecies has been previously photographed underwater in the same locality, the specimens
collected from Yonaguni-jima island represent the first specimen-based records fromJapan. The new Japanese standard name “Hachimonji-utsubo” is proposed for the species.
Formerly, the northernmost record of the species on the basis of collected specimens was

Palau, those reported here representing a ca. 2,200 km northward range extension.
(Corresponding author: Keita Koeda, Kagoshima University Museum, 1–21–30
Korimoto, Kagoshima 890–0065, Japan; e-mail: hatampo@gmail.com)

Japanese Journal of Ichthyology
Vol. 64, No. 1, pp. 37–41

First Japanese record for a species of Pseudoscopelus (Acanthopterygii:Chiasmodontidae) lacking discrete photophores
Fumihito TashiroAbstract

A single specimen (121.5 mm in standard length) belonging to the genus

Pseudoscopelus was collected off the Pacific coast of Tohoku region, Japan. The
specimen was unique among Pseudoscopelus inhabiting Japanese waters in completely
lacking discrete photophores. Although identification was uncertain, primarily due to thetaxonomic confusion among species lacking discrete photophores, the specimen wasprovisionally identified as Pseudoscopelus vityazi Prokofiev and Kukuev, 2007, based on
the following characteristics: silver-colored structures present on head and body insteadof discrete photophores, and internal area of orobranchial chamber dark, at least
posteriorly. Although the original description indicated that the silver-colored structures
were “luminescent tissue”, whether or not those structures are true luminescent organs
still requires verification. A subsequently revised publication date (2008) for P. vityazi isdiscussed. The new standard Japanese name “Ginsen-kurobozugisu” is proposed for thespecies.
(Corresponding author: Fumihito Tashiro, Maizuru Fisheries Research Station, Field
Science Education and Research Center, Kyoto University, Nagahama, Maizuru, Kyoto
625–0086, Japan; e-mail: fumihito.tashiro@gmail.com)

Japanese Journal of Ichthyology
Vol. 64, No. 1, pp. 43–53

Distribution of Anguilla japonica and A. marmorata in the Nansei Islands, Japan,and their habitat segregation based on local names
Yuichi Kano, Tomomi Yamashita, Wataru Tanaka, Akihiko Koyama and Kazuki Kanno
Abstract

The current distribution of the Japanese eel Anguilla japonica and giant

mottled eel A. marmorata were surveyed in 1120 inland water bodies on mainland
Kyushu and the Nansei Islands, southern Japan. Anguilla japonica occurred at 8 and 2sites on Kyushu and the Nansei Islands, respectively, the low catch rate apparently
reflecting its cryptic life style. The likelihood of occurrence of A. japonica in stream
habitats on the Nansei Islands was significantly lower than on mainland Kyushu.
Anguilla marmorata occurred at 46 sites (mostly streams) on the Nansei Islands.
Accordingly, low stream occurrence of A. japonica on the Nansei Islands may haveresulted from interspecific competition. An informal verbal survey of 359 local
respondents indicated that A. japonica had formerly been plentiful in Nansei Islands
paddy fields, although a similar survey on mainland Kyushu found the habitat of A.
japonica to be streams, rivers and/or estuaries. Local names of A. japonica on the Nansei
Islands, including “paddy-dwelling eel” and “mud-dwelling eel”, also indicatedadaptation of A. japonica to a paddy environment, the use of “stream-dwelling eel” for A.
marmorata further suggesting habitat segregation of the two species. The paddy
environment appears to be the primary habitat of A. japonica on the Nansei Islands.
However, such paddy fields have decreased significantly in extent due to a recent cropchange to millet. Restoration of the paddy environment is essential for future A. japonica
conservation on the Nansei Islands.
(Corresponding author: Yuichi Kano, Institute of Decision Science for Sustainable
Society, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819–0395, Japan; e-mail:kano@species.jp)

NotesJapanese Journal of Ichthyology
Vol. 64, No. 1, pp. 55–57

A rare snailfish, Liparis bikunin, collected from Iwate, Japan
Yoshiaki Kai and Tsutomu Noda
Abstract

A single mature female specimen of the rare snailfish Liparis bikunin

Matsubara and Iwai, 1954 was collected from a scallop aquaculture ground in Miyako,
Iwate, Japan. The specimen, representing the southernmost record and second overall of
the species, is described in detail, including the proximal pectoral radials. The species has
been incorrectly characterized as having the anus closer to the anal-fin origin than to thepelvic disk in previous descriptions.
(Corresponding author: Yoshiaki Kai, Maizuru Fisheries Research Station, Field
Science Education and Research Center, Kyoto University, Nagahama, Maizuru, Kyoto
625–0086, Japan; e-mail: mebaru@kais.kyoto-u.ac.jp)

Japanese Journal of Ichthyology
Vol. 64, No. 1, pp. 59–64

An early specimen of Silurus lithophilus (Siluriformes: Siluridae) found in the
Natural History Museum, London
Yusuke Hibino
Abstract

A single specimen of the catfish, Silurus lithophilus (Tomoda, 1961), wasfound in the collection of the Natural History Museum, London. The catalog number ofthe specimen (BMNH 1910.6.30.18) indicates that it was registered on 30 June 1910,
long before the collection of the holotype of S. lithophilus (April 1961), previously
believed to be the first collected example of the species. Accordingly, the Natural History
Museum specimen represents the oldest known example of the species. It is inferred thatthe specimen was collected during the 6th collecting survey of Mr. Richard Gordon
Smith (from November 1905 to mid 1907), the precise date not being apparent in his
excerpted diary published by Ms. Victoria Manthorpe. The collection locality of thespecimen was noted as Kyoto on the jar label and in the museum collection database.
However, a personal tag attached by Mr. Gordon Smith noted its collection from Lake
Biwa. Apparently, the specimen was purchased at Kyoto after having been originallycollected at Lake Biwa.
(Corresponding author: Yusuke Hibino, Laboratory of Fisheries Biology, Faculty ofAgriculture, Kyushu University, 6–10–1 Hakozaki, Higashi-ku, Fukuoka 812–8581,
Japan; e-mail: yusukeelology@gmail.com)