Papers Published in Japanese Journal of Ichthyology
Vol. 66, No. 1, April 25, 2019
CONTENTS
Original Papers
First Japanese record of Sargocentron iota (Beryciformes: Holocentridae) from
Kakeroma Island, Amami Islands, Japan
Kiyoshi Hagiwara and Hiroyuki Motomura
Host mussel suitability for the endangered Itasenpara bitterling Acheilognathus
longipinnis (Cyprinidae, Acheilognathinae) in the Moo River and a conservation pondin Himi, Toyama
Masaki Nishio, Ryosuke Kawakami and Tomonori Kawamoto
Current status of two closely related Phoxinus species, in the Ishi River (Yamato Riverbasin), Osaka Prefecture, Japan
Hiroaki Hata, Tomohiko Fujita, Shun Watanabe and Kazumi Hosoya
Genetic population structure and morphological differences in the mottled skate
Beringraja pulchra
Ryo Misawa, Nozomu Muto, Tomonori Hamatsu, Jin-Koo Kim and Yoshiaki Kai
Ontogenetic morphological changes in artificially-reared larvae and juveniles of the
freshwater goby Rhinogobius kurodai
Kentarou Hirashima
Molecular identification of the closely related gobies Tridentiger brevispinis and T.
obscurus using nuclear DNA markers
Yoshio Tani, Ryotaro Hayashi, Kazuto Takada, Kousuke Oji, Yuki Irie, Takumi Imamura,
Yu Hayakawa and Takahiko Mukai
Rhinogobius biwaensis (“Biwayoshinobori”) × Rhinogobius sp. BF(“Shimahireyoshinobori”) hybrids from the ponds of Sento Imperial Palace, Kyoto City,
Japan
Akihito, Masahiro Aizawa, Yuji Ikeda, Munenori Kishida, Masayoshi Hayashi, Kouji
Nakayama and Tetsuji Nakabo

Effects of fixed and seasonal weirs on the distribution and movements of the endangered
freshwater bagrid catfish Tachysurus tokiensis in rural streams
Tomoko Araki and Masahiro Fujioka
Record of the epigonid fish Epigonus fragilis off northeast Marcus Island, western North
Pacific
Makoto Okamoto

Notes
Distribution of the topmouth gudgeon (Pseudorasbora parva) in the Okhotsk region,
Hokkaido
Takahisa Kanno, Atsuya Yamamoto and Minoru Kanaiwa
Record of Cobitis matsubarae (Cypriniformes, Cobitidae) from the Shonai River, Oyodo
River system, Kagoshima Prefecture, southern Kyushu, Japan
Jun Nakajima, Yasuyuki Hashiguchi, Satoru Sugio, Takashi Higashi, Yukari Koshizako
and Tomoya Taguchi
Variations in otolith morphology of three species of Ammodytes (Perciformes:
Ammodytidae) from the Sea of Okhotsk coast of Hokkaido, Japan
Nozomu Muto and Misa Yamada
Second record of Japanese snook Lates japonicus from Osaka Bay, Japan
Yuki Kimura, Tomoyuki Yamanaka and Shoko Matsui
Marking pattern variants of the pike gudgeon Pseudogobio esocinus from streams in
Niigata and Kyoto Prefectures, Japan
Koji Tominaga and Yuichi Kano

Original Papers
Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 1–5

First Japanese record of Sargocentron iota (Beryciformes: Holocentridae) from
Kakeroma Island, Amami Islands, Japan
Kiyoshi Hagiwara* and Hiroyuki Motomura
Abstract To clarify the ichthyofauna of the Amami Island Ryukyu Archipelago, fish
specimens from the region were examined in museums throughout Japan resulting in the
discovery of a single specimen (75.9 mm standard length; SL) of the dwarf squirrelifish
Sargocentron iota Randall, 1998 (Beryciformes, Holocentridae) in the Yokosuka City
Museum. Collected from a deep (23 m) dark recess in a rocky reef grotto at a rocky reef off
Kakeroma Island. The specimen was characterized by XI, 13 dorsal-fin rays, IV, 9 anal-finrays, 15 pectoral-fin rays, I, 7 pelvic-fin rays, 6 + 10 + 9 + 5 caudal-fin rays, 45 lateral-line
scales, 3.5 scale rows between the mid base of the spinous dorsal fin and the lateral line, 9scale rows between the lateral line and anal-fin origin, 4 oblique scale rows on the cheek, 5 +10 gill rakers, 11 + 16 vertebrae, body depth 2.5 in SL, head length 2.7 in SL, head depth 3.6
in body depth, snout length less than half orbital diameter, upper-jaw length 2.6 in head length,
fourth dorsal-spine longest, third dorsal-fin soft ray longest, a pair of retrorse spines on theedge of the premaxillary groove, a spine on the upper edge of the lacrimal absent, and a bright
red body coloration when fresh. The longest anal-fin soft ray length of the Kakeroma Island
specimen was slightly shorter than that of the type specimens of S. iota which is likely to be
an individual or geographic variation. Although S. iota is distributed in the Indo-Pacific, it has
been recorded only from the Hawaiian Islands and Palau within the North Pacific Ocean.
Accordingly, the Kakeroma Island specimen represents the first record of S. iota fromJapanese waters and the northernmost record for the species. The new standard Japanesename “Kogashira-ebisu” is proposed for the species.
(*Corresponding author: Yokosuka City Museum, 95 Fukadadai, Yokosuka, Kanagawa 238–
0016, Japan; e-mail: kiyoshi-hagiwara@city.yokosuka.kanagawa.jp)
Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 7–13

Host mussel suitability for the endangered Itasenpara bitterling Acheilognathus
longipinnis (Cyprinidae, Acheilognathinae) in the Moo River and a conservation pond in
Himi, Toyama
Masaki Nishio*, Ryosuke Kawakami and Tomonori Kawamoto
Abstract The Itasenpara bitterling Acheilognathus longipinnis is a small cyprinid fish
belonging to the Acheilognathinae, a subfamily that has an unusual symbiotic spawning
relationship with freshwater mussels. During the spawning period, mature males select a
mussel to accommodate spawning of a female. Because females possess short ovipositors for
inserting their eggs inside the suprabranchial cavity of the host mussel via the exhalant siphon,the pattern of mussel utilization by spawning Itasenpara bitterling was investigated in the
Moo River and a conservation pond (Himi City, Toyama Prefecture, Japan), so as to clarify
the most preferred mussel size. In the Moo River (lotic environment), Nodularia douglasiae
nipponensis (38.8% of total 747 individuals) was the major host of A. longipinnis larvae, there
being no obvious size preference, possibly because neither eggs nor larvae of A. longipinnis
could be readily ejected from the host in the lotic environment. By contrast, in theconservation pond (lentic environment), where N. d. nipponensis (24.3% of total 136
individuals) was again the main host of A. longipinnis larvae, a tendency to prefersmaller-sized mussels was apparent, due to the ease of ejection of eggs and larvae of A.
longipinnis from larger-sized hosts (shell length >66 mm) in the lentic environment.
Accordingly, differences in host mussel suitability are suggested as being related to habitat
differences.
(*Corresponding author: The Board of Education, Himi City, 1060 Kurakawa, Himi,
Toyama 935–8686, Japan; e-mail: masaki.nishio@city.himi.lg.jp)
Japanese Journal of Ichthyology
Vol. 66, No.1, pp. 15–22

Current status of two closely related Phoxinus species, in the Ishi River (Yamato Riverbasin), Osaka Prefecture, Japan
Hiroaki Hata, Tomohiko Fujita, Shun Watanabe* and Kazumi Hosoya
Abstract Difficulties in distinguishing between morphologically similar species, such as
Phoxinus lagowskii steindachneri and Phoxinus oxycephalus jouyi, whose distributions
overlap in the Kinki region, are significant for assessments of biodiversity and conservation,in addition to taxonomic status. Morphological analyses were undertaken on Phoxinus
specimens (n = 75) collected in the Ishi and Chihaya rivers (Yamato River basin, Osaka
Prefecture), and compared with type specimens (syntypes of Phoxinus steindachneri, Sauvage,
1883 and paratypes of Leusiscus jouyi, Jordan and Snyder, 1991) and non-type museum
specimens (Phoxinus oxycephalus jouyi). Mitochondrial DNA (mtDNA) analyses of 16
individuals were also undertaken. Two distinct types of Phoxinus were recognized, differingmorphologically in the presence or absence of a black horizontal band on the side of the bodyand scale numbers above the lateral line, and separated by a principal component analysis of 9characters. In addition, 12 haplotypes (identified in the present and previous studies) werevariously associated within two genetically different groups, corresponding to two ecologicaltypes that inhabit the upper and middle parts of the Yamato River, respectively. Because
reproductive isolation is already clearly established between the two types, their recognition
as separate species (Phoxinus lagowskii steindachneri and P. oxycephalus jouyi) in the Ishi
and Chihaya rivers is upheld.
(*Corresponding author: Graduate school of Agriculture, Kindai University, 3327–204
Nakamachi, Nara 631–8505, Japan; e–mail:swpc@nara.kindai.ac.jp)

Japanese Journal of Ichthyology
Vol. 66, No.1, pp. 23–35

Genetic population structure and morphological differences in the mottled skate
Beringraja pulchra
Ryo Misawa*, Nozomu Muto, Tomonori Hamatsu, Jin-Koo Kim and Yoshiaki Kai
Abstract The mottled skate Beringraja pulchra, distributed in the western North Pacific, isa commercially important species, directly targeted by Japanese and Korean fisheries. Despitea recently decreasing catch rate, no studies of population structure, crucial to sustainablefisheries management and conservation practices, are known to have been made. Becauseskates generally have low dispersal ability and are likely to have an extensive population
structure, due to large benthic egg capsules and no pelagic larval stage, the population
structure of the species was assessed on the basis of sequence variations of the mitochondrial
DNA cytochrome c oxidase subunit I (COI) 592 bp (in 166 individuals) and morphologicalvariations in seven morphometric characters (in 192 individuals), representing five areas,
including Hokkaido, Japan [coasts along Sea of Okhotsk, Pacific Ocean, and Sea of Japan(the East Sea of Korea)], western Sea of Japan, and Yellow Sea. The genetic analysis detected
12 haplotypes, six being shared among the sampling areas, although significant pairwise ΦST
estimates indicated restricted gene flow among the sampling areas (excluding those off the
Hokkaido). The extensive population structure of the species was also supported bymorphological differences in several characters, such as disc length, disc width, and eye
diameter. Beringraja pulchra was concluded as being clearly structured into three populations
for future management, viz. Hokkaido, western Sea of Japan, and Yellow Sea populations.
This population structure may have been shaped by the Tsushima Current flowing between
the Korean Peninsula and the Japanese Archipelago, the species generally inhabiting colder
water.
(*Corresponding author: Maizuru Fisheries Research Station, Filed Science Education andResearch Center, Kyoto University, Nagahama, Maizuru, Kyoto 625–0086, Japan; e-mail:batoideafish@gmail.com)
Japanese Journal of Ichthyology
Vol. 66, No.1, pp. 37–42

Ontogenetic morphological changes in artificially-reared larvae and juveniles of the
freshwater goby Rhinogobius kurodai
Kentarou Hirashima*
Abstract
The genus Rhinogobius is widely distributed across Japan and East
Asia, including Japan, comprises amphidromous, fluvial, lacustrine, and land-locked
species. Because R. kurodai (Tanaka 1808) an endemic species formerly known as
Rhinogobius sp. OR (Tou–yoshinobori species complex), in the Kanto region, central Japan,
but recently re-assessed taxonomically, has been less studied from ecological, taxonomic andgenetic perspectives than other Rhinogobius species, this study investigatedontogenetic morphological changes in artificially-reared larvae and juveniles of the former, inaddition to larval salinity tolerance. Larval salinity tolerance is described for
artificially-reared newly -hatched larvae reared in eight tanks (0, 5, 10, 15, 20, 25, 30, and 35
psu). Newly-hatched R. kurodai larvae (3.2 ± 0.1 mm in notochord length) had one or twosymmetrical pairs of cupulae, (free neuromast organs), on the trunk around the anus or tailregion, such having been previously reported in the genus only from larvae of R. sp. BF, alacustrine species Nine days after hatching (4.5 mm in standard length: SL), the notochord
tip projected upwards, and the second dorsal and anal fin ray were formed. Between
eighteen (5.6 mm SL) to twenty-one days (6.4 mm SL), the larvae settled to the bottom of
the aquarium tank. At thirty-five days (11.2 mm SL), all fins and scales were formed(juvenile stage). All larvae subjected to salinities of 20 to 35 psu died within three days,
evidence (together with than of small sized-eggs and ealy presence of larval cupulae)
suggesting that R. kurodai is a lacustrine -type species.
(*Wakayama prefectural museum of natural history, 370–1 Funo, Kainan,
Wakayama Prefecture, Japan; e-mail: hirashima_k0001@pref.wakayama.lg.jp)
Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 43–52

Molecular identification of the closely related gobies Tridentiger brevispinis and T.
obscurus using nuclear DNA markers
Yoshio Tani, Ryotaro Hayashi, Kazuto Takada, Kousuke Oji, Yuki Irie, Takumi Imamura, Yu
Hayakawa and Takahiko Mukai*
Abstract Nuclear DNA (nDNA) markers were developed to distinguish between the closely
related brackish water gobies Tridentiger brevispinis and T. obscurus. Although genetic
differentiation of the two species has already been demonstrated by allozyme analysis inprevious studies, the nucleotide sequences of mitochondrial DNA (mtDNA) haplotypes weresimilar and often shared by introgressive hybridization, obscuring the identification of the two
species by mtDNA markers. In this study, one mtDNA gene [cytochrome b (cytb)] and four
nuclear DNA gene regions [G protein-coupled receptor 85 (gpr85), ryanodine receptor 3(ryr3), recombination activating protein 1 (rag1) and zic family member 1 (zic1)] weresequenced in 11 to 17 individuals, respectively, of T. brevispinis and T. obscurus, collectedfrom the Mukogawa River, Hyogo Prefecture, Japan. The results for the mtDNA cytb region
matched those of previous studies, the nucleotide sequences being very similar, with
haplotypes shared among species. On the other hand, two (gpr85 and ryr3) of the four nDNA
regions clearly differed between the two species, PCR-RFLP conducted on the former also
showing specifically-different electrophoretic patterns. In order to confirm that nDNA
PCR-RFLP could distinguish between the two species in other populations, additional
samples of both from the Shonai River, Aichi Prefecture were subjected to and identified by
the above method. In addition, eight individuals of putative F1 hybrid identified by allozyme
analysis (three diagnostic loci) were also investigated. Although six of the eight putative
hybrids included heterozygotes at both of the two nDNA PCR-RFLP loci, two individuals
were characterized by a heterozygotic pattern at one locus, homozygotic at the other, bothindividuals possibly being F2 or backcross progeny, although initially misidentified as F1.
The results indicated that nDNA markers may be helpful in distinguishing closely related
Tridentiger species, which cannot be identified by mtDNA markers.
(*Corresponding author: Faculty of Regional Studies, Gifu University, 1–1 Yanagido, Gifu
501–1193, Japan; e-mail: tmukai@gifu-u.ac.jp)
Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 53–62

Rhinogobius
biwaensis(“Biwayoshinobori”)
×Rhinogobius
sp.
BF(“Shimahireyoshinobori”) hybrids from the ponds of Sento Imperial Palace, Kyoto City,
Japan
Akihito, Masahiro Aizawa, Yuji Ikeda*, Munenori Kishida, Masayoshi Hayashi, Kouji
Nakayama and Tetsuji Nakabo
Abstract Hybrids of Rhinogobius biwaensis and Rhinogobius sp. BF were identified in theponds of Sento Imperial Palace, Kyoto City, Japan, from microsatellite and mitochondrial
DNA markers. Mitochondrial DNA analysis indicated that five of seven Rhinogobius
specimens had R. biwaensis haplotypes, the remaining specimens having those of
Rhinogobius sp. BF. In DAPC and STRUCTURE analyses based on microsatellite data, allspecimens examined showed intermediate status between R. biwaensis and Rhinogobius sp.
BF, the two species being considered to have formed a hybrid swarm in the ponds because
genetically pure individuals of either were not found. This is the first report of recent
hybridization under field conditions in Rhinogobius fishes from Japan, confirmed by nuclear
and mitochondrial DNA data. Hybrid Rhinogobius specimens from the ponds had 5–17
predorsal scales, an intermediate range between those of non-hybrid R. biwaensis (0–6) andRhinogobius sp. BF (11–20). However, in appearance they were more similar to R. biwaensis
than Rhinogobius sp. BF, having bluish-white distal coloring anteriorly on the first andsecond dorsal fins, a reduced reddish longitudinal band on the anal fin, and lacking yellowish
dorsal and posterior margins on the caudal fin. However, they differed from R. biwaensis in
having a narrower white posterior caudal fin margin. Further morphological differentiation of
the hybrid specimens was not apparent.
(*Corresponding author: Imperial Household Agency, 1–1 Chiyoda, Chiyoda-ku, Tokyo 100–
8111, Japan; e-mail: seiken-ikeda@circus.ocn.ne.jp)
Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 63–78

Effects of fixed and seasonal weirs on the distribution and movements of the endangered
freshwater bagrid catfish Tachysurus tokiensis in rural streams
Tomoko Araki and Masahiro Fujioka*
Abstract The effects of small weirs on freshwater fishes of little or no commercial value
have received scant attention, despite the enormous volume of literature on the negative
impacts of dams and weirs on fishes generally. The distribution and movements of theendangered bagrid catfish Tachysurus tokiensis in a rural area on the Kanto Plain, Japan were
examined, focusing on fish mobility and the effects of small weirs on local abundance. Thirty
survey stations were selected along 3 tributaries of the Koise River (feeding Lake
Kasumigaura). There were 20 weirs, of which 8 functioned only during the irrigation period
from late April to early September. Catfish were caught by electrofishing along 25 m ofstream length at each station in December 2010, and April, July, and October 2011. In total,
483 catfish were caught (average 4.4 fish per survey). Catfish were recorded in all four
surveys at 15 stations (50%) and at least once at 27 stations (90%). Of 298 catfish
individually marked with elastomer color tags, 12 were recaptured once and 2 twice at thesame station as the first capture. Analysis of the relationship between numbers of catfish
captured and environmental factors using generalized linear mixed models (GLMMs)
suggested that the number of downstream weirs might have negatively influenced catfish
numbers, whereas vegetation cover, bottom material, gap height of weirs, and velocity had
little apparent influence. The results suggested that T. tokiensis showed little mobility andoccurred widely throughout the river system, although possibly being negatively affected byweirs.
(*Corresponding author: 1029–24 Negoya, Ishioka, Ibaraki 315–0132, Japan; e-mail:egretta2000@gmail.com)
Vol. 66, No. 1, pp. 79–86

Record of the epigonid fish Epigonus fragilis off northeast Marcus Island, western North
Pacific
Makoto Okamoto*
Abstract In an on-going study of the taxonomy of the genus Epigonus (Perciformes:
Epigonidae), the author found two specimens of E. fragilis (Jordan and Jordan, 1922)
collected off northeast Marcus Island (Minami Torishima), western North Pacific, were foundin the Fish Collection of Kyoto University, Maizuru Fisheries Research Station, Kyoto(FAKU). The species having been previously reported from Johnston Atoll, the Hawaiian
Islands, and the Colahan Seamount, and Milwaukee Bank (Emperor Seamount chain), thespecimens represent the first report of the species from waters adjacent to Japan. The newstandard Japanese name “Ibushigin-yasemutsu” is proposed for the species, which belongs to
the E. pandionis group, defined by Okamoto and Motomura (2013), and is characterized by
the following combination of characters: dorsal fin rays VII-I, 10; pectoral fin rays 17 or 18;
gill rakers 25–27; vertebrae 10 + 15; pyloric caeca 7 or 8; pored lateral-line scales 46–49 + 3
or 4; pungent opercular spine absent; maxillary mustache-like process absent; lingual teeth
absent; small conical teeth on lower jaw; pair of ribs present on last abdominal vertebra;
tubercle on inner symphysis of lower jaw absent; orbital diameter 13.5–15.2% SL; andpectoral-fin length 22.8–26.1% SL. Besides E. fragilis, four species of Epigonus have beenrecorded from Japan, viz., E. atherinoides (Gilbert, 1905); E. ctenolepis Mochizuki and
Shirakihara, 1983; E. denticulatus Dieuzeide, 1950; and E. pectinifer Mayer, 1974. A key to
the Japanese species of Epigonus and list of Japanese standard names of Epigonus speciesworldwide is included.
(*Marine Fisheries Research and Development Center, Japan Fisheries Research and
Education Agency, 15F Queen’s Tower B, 2–3–3 Minatomirai, Nishi-ku, Yokohama,
Kanagawa 220–6115, Japan; e-mail: epigonidae@gmail.com)

Notes
Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 87–91

Distribution of the topmouth gudgeon (Pseudorasbora parva) in the Okhotsk region,
Hokkaido
Takahisa Kanno, Atsuya Yamamoto and Minoru Kanaiwa*
Abstract Topmouth gudgeon (Pseudorasbora parva; Japanese name, motsugo), originally
distributed in western Honshu, Shikoku and Kyushu, has been artificially introduced wellnorth of its natural distribution area, to the Tohoku region and Hokkaido. The occurrence of
topmouth gudgeon in the pond of Notsukeushi park at Kitami City, Hokkaido, the first recordof the species in the Okhotsk region, was established and the population size estimated using
the mark-recapture method. Although more than 2,000 fish between 1 and 4 years old were
determined as living in the pond, none were found in either the inflow and outflow rivers,
despite their apparent suitability. Further efforts in public educations are required to prevent
further spreading of this fish.
(*Corresponding author: Graduate School and Faculty of Bioresources, Mie University,
1577 Kurima Machiya-cho,Tsu, Mie 514-8507, Japan; e-mail: kanaiwa@bio.mie-u.ac.jp)
Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 93–100

Record of Cobitis matsubarae (Cypriniformes, Cobitidae) from the Shonai River, Oyodo
River system, Kagoshima Prefecture, southern Kyushu, Japan
Jun Nakajima*, Yasuyuki Hashiguchi, Satoru Sugio, Takashi Higashi, Yukari Koshizako andTomoya Taguchi
Abstract Two voucher specimens of the spined loach, Cobitis matsubarae Okada and Ikeda,
1939, collected from the Shonai River, a branch river of the Oyodo River system, southern
Kyushu, Japan, represent the first reliable record of that species from the Oyodo River system.
Morphological features of the male lamina circularis, prepelvic myotome number, maxillarybarbel length, snout length, body pigmentation patterns, and genetic characteristics of mtDNA
cytb sequences were in close agreement with characters those of C. matsubarae. Together
with C. sakahoko, C. matsubarae, is considered to be distributed naturally in the Oyodo Riversystem(*Corresponding author: Fukuoka Institute of Health and Environmental Sciences,
Mukaizano 39, Dazaifu, Fukuoka, 818–0135, Japan; e-mail: cyprin@kyudai.jp)

Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 101–108

Variations in otolith morphology of three species of Ammodytes (Perciformes:
Ammodytidae) from the Sea of Okhotsk coast of Hokkaido, Japan
Nozomu Muto* and Misa Yamada
Abstract Inter- and intraspecific variations in 2-dimensional otolith morphology were
investigated in three sympatric species of Ammodytes (Perciformes: Ammodytidae) fromJapan, viz., A. japonicus Duncker and Mohr, 1939, A. hexapterus Pallas, 1814 and A. heianOrr, Wildes and Kai, 2015. Size-dependent measurements and elliptic Fourier analyses ofotolith outlines failed to show significant differences among the three species. However, bothinvestigating methods revealed intraspecific variations relative to body length in each species,
indicating ontogenetic changes in otolith morphology. The occurrence of several outlier
specimens suggested a variable pattern of ontogenetic changes among individuals and/or
between developmental stages(*Corresponding author: Department of Marine Biology and Sciences, School of Biological
Sciences, Tokai University, 5–1–1–1 Minamisawa, Minami-ku, Sapporo, Hokkaido 005–
8601, Japan; e-mail: nzmutou@tsc.u-tokai.ac.jp)
Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 109–111

Second record of Japanese snook Lates japonicus from Osaka Bay, Japan
Yuki Kimura*, Tomoyuki Yamanaka and Shoko Matsui
Abstract A single female specimen (724 mm SL) of Japanese snook, Lates japonicus
Katayama and Taki, 1984, was corrected in the mouth of the Ajigawa river, Osaka Bay, Japanon 20th August 2018, representing the second record of the species from Osaka Bay. The
present record implicates that this fish was not resident but appeared accidentally in Osakabay, because the bay lacks no suitable over-wintering habitat for L. japonicus.
(*Corresponding author: Research Institute of Environment, Agriculture and Fisheries,
Osaka Prefecture, 2926–1 Tanagawa-tanigawa, Misaki, Sennann, Osaka, 599–0311, Japan;
e-mail: KimuraY@o-suishi.zaqrs.jp)
Japanese Journal of Ichthyology
Vol. 66, No. 1, pp. 113–117

Marking pattern variants of the pike gudgeon Pseudogobio esocinus from streams in
Niigata and Kyoto Prefectures, Japan
Koji Tominaga* and Yuichi Kano
Abstract Marking pattern variants of the pike gudgeon Pseudogobio esocinus are reported
from streams in Niigata and Kyoto Prefectures, Japan. The variant specimens have lost mostof the body markings observed in normal specimens, i.e., dark blotches and small black spots
on the lateral and dorsal sides of the body, and small black spots on the dorsal, pectoral, andcaudal fins. In addition, a specimen from Kyoto Prefecture had a narrow black lateral stripe

on the body instead of a narrow yellow-gold stripe under dark blotches. Mitochondrial DNA
sequence variations seen in the variant specimens from the two streams suggest that they were
derived from their respective indigenous populations.
(*Corresponding author: Kwansei Gakuin Senior High School, 1–155 Uegaharaichibancho,
Nishinomiya, Hyogo 662-8501, Japan; e-mail: tominaga@kwansei.ac.jp)