著者

渡辺 勝敏 前田 洋志

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.41, no.4, pp.409-420, 1995-02-21 (Released:2010-06-28)

参考文献数

23

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遺伝学的に別種であることが示されている日本産ギギ科魚類2種, Pseudobagrus aurantiacus (Temminck and Schlegel) (アリアケギバチ) とそのシノニムとして扱われてきたP. tokiensis Döderlein (ギバチ) について, 模式標本を含む多数の標本を基に両種を再記載し, 形態比較を行った.その結果, P. aurantiacusは, より高い背鰭, 胸鰭棘前縁を広く覆う顕著な鋸歯列, 外向きの1-3歯を伴うより高密度な同後縁鋸歯列, より幅広い上後頭骨突起, 上後頭骨突起と同程度の長さの大きな上神経骨, 幅広い擬鎖骨後方突起 (後端>20°), 外翼状骨から大きく離れた舌顎骨前縁より明瞭な若魚の体斑パターン, 等によってP. tokiensisから区別された.

著者

黒田 長禮

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.2, no.6, pp.271-284, 1953-03-31 (Released:2010-06-28)

参考文献数

34

被引用文献数

1

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The present article contains an introductory notes on Lake Biwa with some notes on the fishes, a brief history of the study on the fishes of this lake, from 1806 to the most recent (1951), and a complete list of the fishes of Lake Biwa (45 species and subspecies found in the lake itself, in addition to two species found near this lake and 13 introduced species) with their distribution records in Japan and the neighbouring couneries.The mark × indicates simply the occur ence of the species or forms found in the region named at the top of the column and the mark _??_, that the same is known to be found as an introduced species in the region.Next I have given the names of localities around or near Lake Biwa with the names of collected fishes in old and new records.Lastly, in my conclusion concerning the distribution of these fresh water fishes found in this lake, I have noted two endemic forms: Gnathopogon elongatus caerulescens and Chaenogobius annularis isaza; 19 species are confined to the Japanese waters, and most of the remaining ones (about 30) are common to the Asiatic Continent in their distribution.

著者

樋口 淳也 Kim Seong-yong 河合 俊郎

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

pp.23-013, (Released:2023-10-05)

参考文献数

27

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A single specimen of Krusensterniella (Perciformes: Zoarcidae), collected off Tsugaru Peninsula, Aomori, Japan, was identified as Krusensterniella squamosa Chernova, 2022, characterized by three pungent spines in the dorsal fin, 47 dorsal-fin spines, at least 101 dorsal-fin rays and 103 vertebrae, and previously known only from the holotype, collected off Iwate, Japan. The new standard Japanese name “Uroko-haregaji”, referring to the scaled body, is proposed for the species. Records of Krusensterniella notabilis from Japan are unlikely to be that species, since many identification sources for Japanese fishes in correctly described K. notabilis as having a broad scaled area on the body.

著者

渡辺 勝敏 高橋 洋 北村 晃寿 横山 良太 北川 忠生 武島 弘彦 佐藤 俊平 山本 祥一郎 竹花 佑介 向井 貴彦 大原 健一 井口 恵一朗

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.53, no.1, pp.1-38, 2006-05-25 (Released:2010-06-28)

参考文献数

247

被引用文献数

6

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The biogeography of freshwater fishes in Japan was reviewed in terms of achievements and perspectives. In the last three decades, biogeographic studies have changed from earlier descriptions of the freshwater fish fauna, based on the Linnean classification system, to phylogenetic approaches using various molecular markers. Especially, the phylogeographic approach, which explores the formation of geographic distribution patterns of genealogical lineages within species, has become predominant. Analyses of genuine freshwater fishes have disclosed their speciation and dispersal patterns throughout temperate East Asia since the Neogene, along with the formation of the Japanese Archipelago. In particular, molecular clocks of mitochondrial DNA have played an important role in examinations of biogeographic relationships between the Japanese Archipelago and Chinese continent/Korean Peninsula, and vicariance by Fossa Magna in central Honshu Island. Patterns of range expansion through the sea and landlocking in coldtemperature euryhaline fishes have indicated their speciation and distribution dynamics under the fluctuating climatic conditions of the Plio-Pleistocene. Likewise, phylogeographic implications of unusual biological entities arising from interspecific hybridization or gynogenesis have been discussed. Nevertheless, despite the emphases given to some groups, the present knowledge of phylogeographic patterns of Japanese freshwater fishes is for the most part still insufficient for quantitative analyses of the overall history of the freshwater fish fauna and geographic regions of Japan. Improved research techniques and methodologies for the integration of findings from multiple taxa and/or genes are essential. Further, evolutionary formation of distributional ranges should be considered together with ecological biogeography, including the processes of local adaptation, interspecific interaction and extinction. Modern day disturbances of freshwater fish distributions, including fish transportation, are rapidly leading to artificial distribution patterns and extinctions. Exhaustive phylogeographic analyses should be necessary as a primary requirement for conserving freshwater fish biodiversity in Japan.

著者

加納 光樹 小池 哲 河野 博

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.47, no.2, pp.115-129, 2000-11-27 (Released:2010-06-28)

参考文献数

44

被引用文献数

9

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A total of 61, 388 fish specimens, representing about 60 species, were collected by monthly seine-net (mesh size 0.8 mm) samplings at the seven tidelands in the inner Tokyo Bay, Pacific coast of central Japan, from April 1997 to March 1998. Two gobiid species, Acanthogobius flavimanus and Chaenogobius macrognathos, were the most abundant species, contributing 52.6 and 20.7% of the total number of fishes, followed by Chaenogobius castaneus (7.7%), Lateolabrax japonicus (6.3%) and Mugil cephalus cephalus (6.0%). Eight “estuarine” and 19 “marine” species, which occupying 99.4% of total number of fishes, were highly possibly c0onsidered to depend on tidelands for their considerable part of life history, because of the occurrence of some developmental stages. The diversity of fish community was higher in Obitsu River and Edo River than in other five sites, in the first two rivers, large tidelands having remained in spite of coastal construction since 1950's. The results of this study would indicate that the diversity of fish community at tidelands reflect more or less an impact of emvironmental changes by the reclamation of the inner Tokyo Bay.

著者

中島 廉太朗 美馬 純一 鬼倉 徳雄 向井 貴彦

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

pp.22-003, (Released:2022-12-26)

参考文献数

62

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The phylogeographic patterns of freshwater fishes provide clues for understanding the relationships between geological events and biota formation. In central Honshu, Japan, many mountain ranges (e.g., the Fossa Magna) divide watershed areas, resulting in long-term biogeographical barriers to the freshwater fishes. Almost all of the freshwater fishes from the upland areas, however, occur naturally in more than one river system. Such ichthyofaunal similarity among river systems is hypothesized as having resulted from headwater river captures. Accordingly, to clarify the processes behind present-day ichthyofaunal patterns in the upland area of central Honshu, the present study investigated the mitochondrial phylogeographic pattern of upstream fat minnow, Rhynchocypris oxycephala, distributed in mountainous streams in western Japan. The phylogenetic analyses, using mitochondrial cytochrome b gene sequences (1,140 bp) obtained from 451 individuals from 86 sites throughout the species distribution range, indicated eight major clades in Japan. Of these, the Biwa-Tokai clade was distributed in the major area of central Honshu, and divided into three geographically differentiated groups: (i) Lake Biwa group in the tributaries that flow into Lake Biwa; (ii) Ise Bay group in the Pacific drainages that flow into Ise Bay, and (iii) Hida group in the Japan Sea drainages. These groups were isolated by watershed areas in the IbukiSuzuka and Hida Mountains. However, haplotype distributions in the headwaters of the Shou (Japan Sea side) and Nagara Rivers (Pacific side) suggested former dispersal of freshwater fishes from the Pacific to Japan Sea drainages via river capture in the Hirugano Highlands watershed area. Similar distributions of mtDNA haplotypes observed in three other headwater areas also suggested previous river captures. During the present study, however, some mtDNA haplotypes collected from Gifu, Shizuoka and Kanagawa Prefectures were found to be identical to those in the Lake Biwa group, suggesting that artificial transplantations of R. oxycephala had occurred in several areas.

著者

千田 哲資 星野 暹

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.17, no.1, pp.1-6, 1970-04-15 (Released:2010-06-28)

参考文献数

9

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岡山県を中心とする瀬戸内海の一部にウロハゼを対象としておこなわれるはぜつぼ漁業の漁期は6月下旬-8月上旬, 漁場は沿岸の浅海域で, 漁期を通じ日々の漁獲率は20%程度である.はぜつぼで獲れるのはほとんどウロハゼに限られ, 他にはテンジクダイ, メバルなどが極く稀に漁獲される.1個のつぼで同時に獲れるウロハゼは1尾または2尾である.1尾のときは雄または雌で前者であることの方が多い.2尾のときは原則として雌雄で, 通常雄の方が大きい.雌の卵巣は発達し, つぼに入るのは産卵前行動としての巣ごもりである.近年一部の地方で用いられている木箱による漁獲率は従来のはぜつぼによるそれよりよく, ウロハゼの産卵室としてよりすぐれている.はぜつぼ漁業が漁業として成立することは, 天然の産卵室が相対的に不足していることを示すと考えられる.産卵群は体長により四つの成分に分けられるが, これらの各成分が各年令群に対応するか否か明らかでない.雌は雄よりも成長が遅いように思われ, 最大体長は雄が大きい.全国的にみたとき本種はほとんど利用されていない.食用としての利用とともに, 海産動物の幼生飼育にあたって餌料として本種の孵化仔魚を利用することも可能と思われる.

著者

明仁親王

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.11, no.1-2, pp.1-26, 1963-12-15 (Released:2010-06-28)

参考文献数

10

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1. 肩胛骨の有無, 形態をハゼ科魚類67種についてアリザリン染色によって調べた。これらは次のように分類された。有肩胛骨型47種肩胛骨はよく発達し背方から肩胛骨孔をかこんで二叉するが, 完全に孔をとりかこむものはない。射出骨のうすく染まる体長の小さい時期から肩胛骨は染色点或は棒として現われる。特殊型2種有肩胛骨型より肩胛骨の発達の不十分な型で無肩胛骨型との中間に位する。射出骨の十分に染まった体長の大きな個体でも染色されないものがあり, 又肩胛骨のある場合でも二叉はしないように思われる。無肩胛骨型18種肩胛骨を欠く型である。シロウオを除き射出骨, 烏喙骨の骨化は他の型と変りがない。2. 肩胛骨の形は個体変異が著しく, 種の特徴として重要視することはむずかしいが, 肩胛骨の有無は十分に成熟した個体では特殊型を除き種によって決まっており, 種を区別するには安定した一形質とみなされる。3. 肩胛骨の有無は属を区別する一つの特徴として取り上げ得ると考えられる。

著者

赤田 仁典 淀 太我

出版者

日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.53, no.2, pp.175-179, 2006-11-25 (Released:2010-06-28)

参考文献数

8

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Between-habitat variations in the body shape of Hemigrammocypris rasborella, a small freshwater cyprinid fish included in the Red List by the Ministry of Environment of Japan (Category EN), were analyzed using photographs of anesthetized specimens (n=323) collected from eight ponds on the Ise (Mie Prefecture) and Nobi Plains (Aichi and Gifu prefectures). Twenty-two morphometric variables were measured, and principal component and discriminant analyses conducted. The results indicated that body shape was variable among the ponds but similar within each plain. It is suggested that the original Ise and Nobi Plain populations differed in body shape, the subsequent restriction to isolated populations on each plain further enhancing the original morphological variations.

著者

古満 啓介 山口 敦子

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

pp.20-042, (Released:2021-06-12)

参考文献数

27

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Six specimens collected from Kochi, Nagasaki, Kagoshima, and Okinawa Prefectures, on the Pacific Coast and the East China Sea, and seven museum specimens, were identified as the purple ray Myliobatis hamlyni Ogilby, 1911, based on a combination of specific morphological characteristics. Initially considered an Australian endemic, subsequent studies have shown M. hamlyni to have a patchy distribution from the Australian coast to Japan, the latter record being based on a single specimen collected from Okinawa Prefecture. However, the current study has revealed the widespread distribution of M. hamlyni in waters from the surface to 500 m depth off southwestern and western Japan, a specimen from Kanagawa Prefecture representing the northernmost record of the species. Because the distribution of M. hamlyni may broadly overlaps that of the Japanese species M. tobijei, and morphometric characters and depth preference separating them suggested in the previous study were unclear, detailed comparisons were made so as to establish a basis for distinguishing between the two species in the present study. Myliobatis hamlyni differs most clearly from M. tobijei as follows: greatest span of pelvic fins 20.9–24.7% (mean 23.5%) of disc width [vs. 27.1–36.3% (30.7%) in M. tobijei], greatest span of pelvic fins 44.5–53.6% (50.4%) of pectoral-fin posterior margins [vs. 58.8–78.5% (67.4%)], and distance from edge of disc to first gill slit 51.0–68.3% (57.6%) of distance from pectoral-fin insertion to dorsal-fin origin (horizontal) [vs. 32.4–44.7% (41.3%)]. The new standard Japanese name “Sumire-tobiei” is proposed for M. hamlyni.

著者

明仁親王 目黒 勝介

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:18847374)

巻号頁・発行日

vol.34, no.4, pp.409-420, 1988

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ロクラハゼ属の2種キマダラハゼ<I>Astrabe flavima-culata</I>とシマシロクラハゼ<I>A. fasciata</I>を新種として記載し, シロクラハゼ属の模式種であり, 今まで知られていた唯一の種であるシロクラハゼ<I>A. lactisella</I>についても前2種と比較して再記載した.キマダラハゼは日本産魚類大図鑑の中でキマダラハゼ<I>Astrabe sp</I>.として明仁親王 (1984) が解説を付したものである.キマダラハゼはシロクラハゼとは眼の上縁にある皮摺の上後部が突出しないこと, 縦列鱗数が少ないこと, 第1背鰭前方と腹部に鱗があること, 胸鰭基部を通る白色横帯の幅が狭いこと, 生時には胸鰭基部を通る白色横帯を除き, 暗褐色地に黄色模様が見られることによって区別される.シマシロクラハゼはシロクラハゼとは横列鱗数が少ないこと, 体側の鱗のある部分の幅が狭いこと, 胸鰭基部を通る白色横帯の幅が狭いこと, 第1背鰭前部から体の腹側に向かう白色横帯があることによって区別される.この度の標本の調査により, Snyder (1912) が記録した種子島産の<I>A. lactisella</I>はキマダラハゼであり, 本間・田村 (1972) が記録した佐渡島達者産のシロクラハゼはシマシロクラハゼであることが判明したので, これらの標本はそれぞれの種の副模式標本とした.また道津.塩垣 (1971) がシロクラハゼとして扱ったものの中, 標本を調べることが出来た鹿児島県馬毛島産のものはキマダラハゼであった.長崎県野母崎産の標本は図から判断するとシマシロクラハゼと考えられる.明仁親王 (1984) のシロクラハゼとキマダラハゼの解説は訂正しなければならない.

著者

水口 憲哉 檜山 義夫

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.16, no.1, pp.17-23, 1969-06-15 (Released:2010-06-28)

参考文献数

11

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東京都下秋川において行なった調査により, オイカワZacco platypusの成熟および臀鰭の性徴について以下の点を明らかにした.1) 6月から8月の産卵期に, 雄はよく発達した追い星, 体側の赤および青緑色, そして異常に発達した臀鰭などによって特徴づけられた.III+才魚およびII+才雄の半数よりなるこれらの成熟雄は産卵活動を行ない9月までに死に絶えてしまった.2) II+才雄の残り半数は, 何ら二次性徴を示さず, 細い糸状の精巣をもったままで産卵期を経過してしまったため, 上述の成熟雄に対し“非成熟”雄とされた.“非成熟”雄は, 夏期にも成長を続け翌年の産卵期にIII+才魚として成熟した.3) 成熟雌においてもその程度は低いが臀鰭における形態的変化がおこった.雌はほとんどがII+才で産卵を開始しIII+才で2回目の産卵を行なった後に姿を消した.4) 5月から8月にかけては, 全長80mm以上のオイヵワについて臀鰭長により雌雄の判定が可能であり, また, 特に雄においては性的成熟の度合を知ることができる.5) 鱗に表われた過去の成長状態を参考にして, 雄が成熟または“非成熟”へと別れる過程およびII+才雄全体に対する“非成熟”雄の割合などについて考察した.

著者

Moyer Jack T. Zaiser Martha J.

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:18847374)

巻号頁・発行日

vol.28, no.4, pp.466-468, 1982

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1980年8月15日16時30分, 三宅島の水深12mの地点で全長約90cmの2尾のウツボ<I>Gymnotborax kidaka</I>が産卵しているのを観察した.両者は尾部をゆるくからませていたが, 突然腹部を押しつけ合ってから離れた.その瞬間精子による水の白濁が観察された.卵は直径約2mmの丸い浮性卵で, 親魚による卵の保護は観察されなかった.1980年7月29目19時30分には, 岸近くの水深2.5mの地点で, 全長約25cmの<I>Uropterygtus necturus</I>4尾が群がって行動しているのを観察した.これは産卵直前の行動と思われた.

著者

向井 貴彦 西田 睦

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.50, no.1, pp.71-76, 2003-05-23 (Released:2010-06-28)

参考文献数

24

被引用文献数

1

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Phylogenetic relationships among 4 major geographic population groups (San-in-Biwa-Ise, East Seto, West Seto and West Kyushu) of Japanese freshwater goby Odontobutis obscura (Perciformes: Gobioidei: Odontobutidae) and related species O. hikimius were inferred from partial nucleotide sequences of the mitochondrial 12S and 16S rRNA genes. The resultant mitochondrial DNA (mtDNA) phylogeny was consistent with that based on the previous allozyme analysis. This phylogeny showed that specimens from the Sagami River system in Kanagawa Prefecture, Kanto District, were extremely close to fish from the West Seto group, suggesting the formers to have been descended from individuals artifi-cially introduced from the range of the latters. Judging from the fact that about 40 individuals of the goby were easily collected by a person in 2 hrs, the Kanto popu-lation did not seem to be small, and thus might be disturbing the native fauna in the river system.

著者

馬渕 浩司 西田 一也 吉田 誠

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

pp.19-012, (Released:2019-08-10)

参考文献数

23

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A total of 351 eggs from 12 egg populations was collected in June 2018 from a revetmented tributary of the Chounogi River, ca. 2 km upstream from Lake Biwa. Analysis of 95 of these eggs (sampled about equally from all populations) by a 2 or 3-step DNA identification process resulted in 71 being successfully sorted into the following five taxa: Gnathopogon caerulescens (25 eggs), Carassius buergeri grandoculis (22), triploid Carassius (4), and Japanese (8) and Eurasian (12) species of Cyprinus. Of these five taxa, G. caerulescens, C. buergeri grandoculis, and Japanese Cyprinus sp. are thought to migrate upstream to spawn, as they are more commonly found in the lake. Notably, 60% of the collected eggs were attached to the substrata provided by riverside trees (the remaining 40% were attached to vegetation hanging into the stream). Unfortunately, these trees were removed during a river renovation procedure conducted just after this study.

著者

大森 健策 加納 光樹 碓井 星二 増子 勝男 篠原 現人 都築 隆禎 横井 謙一

出版者

日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

pp.18-019, (Released:2018-08-20)

参考文献数

64

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Large-scale Japanese lakes support many fish species and abundant fisheries resources. However, long-term changes in the fish fauna of such lakes have not been fully investigated, despite recent significant anthropogenic impacts on associated ecosystems. Accordingly, the extensive native and non-native fish fauna of Lake Kitaura, a typical large inland-sea lake (36 km2) in eastern Japan, was investigated based on specimens collected by the staff of Itako Hydrobiological Station, Ibaraki University from 1977 to 1997, plus data from previous studies conducted since the 1950s. In total, 83 species in 35 families have been recorded from the lake from the 1950s to the present decade. The analyses of long-term changes in fish species data since the 1960s demonstrated a sharp decrease in marine, estuarine and diadromous species due to an estuarine barrage (Hitachi River floodgate) established in 1973, the disappearance of nine red-list species (e.g., threatened and near threatened species) following various artificial environmental changes from the 1960s to 1980s, and an increase in introduced exotic and Japanese species after the 1980s.

著者

仲谷 一宏

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.20, no.2, pp.120-122, 1973-09-10 (Released:2010-06-28)

参考文献数

9

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1964年1月, インド洋で全長1850mmの白いトラフザメが捕獲された. この個体と正常なトラフザメを比較した結果, この白いトラフザメと正常なトラフザメの間の唯一の差は体色で, 眼の色を含め他の形質にはまったく差異が見られなかった. したがって, 本個体をトラフザメの不完全な白子 (partial albino) と断定した.現在まで板鯉魚類の白化現象は本例を含め10例が報告されているが, 本例のように大きな個体は珍らしく興味深い.

著者

松沼 瑞樹 内田 喜隆 田城 文人

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.66, no.2, pp.253-260, 2019 (Released:2019-11-28)

参考文献数

11

被引用文献数

1

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A single specimen of Scomberoides commersonnianus (Carangidae), previously recorded only from Kagoshima, Miyazaki and Toyama prefectures in Japan, was recently collected off Yamaguchi Prefecture (34˚25.3'N, 131˚21.0'E), southwestern Japan Sea. The newly collected specimen (FAKU 146095, 401.8 mm SL, 424.8 mm FL), representing the fourth Japanese record of the species, was probably transported by the Tsushima Current, flowing northward off the west coast of Kyushu and the Japan Sea coast of mainland Japan. A checklist of 27 carangid fishes found in Wakasa Bay and adjacent waters, central Japan Sea coast of Japan is also provided.

著者

ジョン ビョル 大富 潤 本村 浩之

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

pp.22-018, (Released:2023-03-08)

参考文献数

25

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Four specimens (390.5–576.0 mm standard length; SL) of Etelis boweni Andrews, Fernandez-Silva, Randall and Ho, 2021 (Perciformes: Lutjanidae), collected from the Osumi Islands, Kagoshima Prefecture, Japan, were similar to Etelis carbunculus Cuvier, 1828 in sharing the following characters: dorsal fin with a deep notch and lacking scales; maxilla covered with scales; caudal-fin lower lobe whitish; and length of caudal-fin upper lobe greater than 3.3 in SL. However, the specimens differed from E. carbunculus in having the opercular spine posterior end rounded (pointed in the latter), 14 scale rows below the lateral line (vs. 12), and tip of the caudal-fin upper lobe black in both fresh and preserved specimens (vs. reddish in fresh specimens, yellowish in preserved specimens). Furthermore, a sequence analysis of the mitochondrial cytochrome oxidase I gene of the four Osumi Islands’ specimens showed a divergence of only 0.0–0.5% from the holotype of E. boweni, the five specimens comprising a clade separated by 7.5–8.8% sequence divergence from E. carbunculus. Although E. boweni is widely distributed in the IndoWest Pacific (from the Red Sea and Seychelles to Samoa), the Osumi Islands’ specimens (for which the standard Japanese name “Oo-akamutsu” is newly proposed) represent the first specimen-based records of Etelis boweni from Japanese waters as well as from the northwestern Pacific Ocean. Additionally, the apparently sympatric occurrence of E. boweni and E. carbunculus was evidenced by the collection together of the two species (KAUM–I. 160343, 390.5 mm SL and KAUM–I. 160342, 407.9 mm SL, respectively).

著者

向井 貴彦 橋本 昌尚

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

pp.22-021, (Released:2023-02-24)

参考文献数

41

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The weather loach Misgurnus anguillicaudatus, an important freshwater fish in rural areas of Japan, although comprising both native and non-native mitochondrial DNA lineages, exists in reduced populations in many prefectures and is listed as NT (Near Threatened) in the Red List (Ministry of the Environment of Japan, 2020). On the other hand, the pond loach M. dabryanus, introduced into Japan from continental Asia, is expanding its distribution in various parts of the country. A survey of the spatial distributions of M. anguillicaudatus (native and non-native lineages) and M. dabryanus in Ichinomiya (113.8 km2), Aichi Prefecture, Japan, examined 117 agricultural ditch sites for presence/absence of the loaches from May to August, 2020. Native and non-native M. anguillicaudatus were identified by mitochondrial cytb gene sequencing. Although loaches were collected from 52 of 117 sites, M. dabryanus was dominant (293 individuals from 41 sites) over M. anguillicaudatus (55 individuals from 14 sites), the species co-occurring at only three sites. The relationships between loach presence and several environmental factors were analyzed using the generalized linear model (GLM), which showed that the probability of loach presence (either species) was mainly explained by the presence of ditch vegetation (positive effect) and proportion of agricultural land use (but not paddy fields) (negative effect). The probability of M. anguillicaudatus presence (versus M. dabryanus) was mainly explained by water depth in winter. The results indicated that an increase in concrete ditch construction (no vegetation) and conversion of paddy fields to other agricultural usages, may result in habitat reduction for both species, whereas a decrease in water depth in winter may promote an increase in M. dabryanus. The mtDNA analysis showed that the native lineage of M. anguillicaudatus was found in only 7 sites, thus being critically endangered in the area.