著者
小山 直人 北川 忠生
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.56, no.2, pp.153-157, 2009 (Released:2014-03-05)

In order to examine genetic introgression from the orange-red type commercial strain of Oryzias latipes (himedaka) to wild medaka populations, a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the mitochondrial cytochrome b gene was conducted for 45 populations from the Yamato River system, Nara Prefecture and two fish farm populations from special product grounds of himedaka (Yamatokoriyama and Yatomi Cities). Orange-red type fish only were collected from three sites, and a mixture of wild and orange-red types from sympatric populations at four other sites in theYamato R. system. Most orange-red type specimens had the B27 mitotype, being identical with that of the typical orange-red type Hd-rR strain. Although most of the wild type fish individuals had mitotype B1a, inferred as one of the native mitotypes in the Yamato R., four from three sites had mitotype B27, implying genetic introgression from himedaka to wild medaka populations.
著者
馬渕 浩司 瀬能 宏 武島 弘彦 中井 克樹 西田 睦
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.57, no.1, pp.1-12, 2010 (Released:2014-03-05)
参考文献数
22

A recent mitochondrial (mt) DNA survey revealed that the native Japanese population of the common carp has been endangered by the introduction of non-native domesticated strains: more than half of the haplotypes detected so far in Japanese waters originated from Eurasian strains. In expectation that Lake Biwa, the largest freshwater body in Japan, contains a relatively pure native population, we conducted a survey of mtDNA haplotypes in the lake, collecting 856 common carp from 40 localities in the lake. Of these, 606 specimens were caught by various nets (gill net, set net, net trap, etc.) used at depths from 1 to 5 m, 148 specimens were caught by a trawl net used at depths from 30-70 m, and 102 specimens that had washed ashore during mass mortality caused by Koi herpes virus (KHV) in 2004 were collected by hand. For each of the specimens, the mitochondria- encoded cytochrome b gene was genotyped (Japanese native or non-native haplotypes) by PCR using allele-specific primers. Analysis of haplotype frequencies showed that the native Japanese haplotype was significantly more frequent in deep off-shore waters and waters along the steep northern coast of the North Basin (about 80% on average), than in shallow coastal waters in the South Basin and waters along the eastern coast of the North Basin (less than 50% on average). These results indicate that the deep waters of the lake may contain a relatively pure native population that is of prime importance for conserving the native Japanese common carp. Among the results, it is notable that more than 90% of the KHV-killed specimens had native Japanese haplotypes.
著者
加藤 文男
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.28, no.2, pp.184-186, 1981-08-15 (Released:2011-02-23)
被引用文献数
1 or 0

Three specimens of the amago salmon, Oncorhynchus rhodurus, were caught off Chikubu Island in Lake Biwa, Shiga Prefecture, Japan. These specimens were females measuring 260-375 mm in standard length, with red spots on both sides of the body.The transverse scale counts above the lateral line were 27-32.Ridges of scales had disappeared in the apical margin of the scales.These characters resemble those of the amago salmon found in the Nagara River or Lake Suwa, and differ from those of the Biwa salmon found in Lake Biwa (Kato, 1973a, 1975a, b, 1978).Therefore the author identified the specimens as amago salmon.They are presumed to have descended in the smolt stage into Lake Biwa and to have grown there.
著者
澤志 泰正 西田 睦
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.41, no.3, pp.253-260, 1994-11-21 (Released:2010-06-28)

現在の唯一の生息地である奄美大島において, リュウキュウアユは不連続な東西2地域 (住用・伊須湾域と焼内湾域) に分布する.この両地域の集団がどの程度独立であるかを明らかにするため, 生態学的側面および遺伝学的側面の両面から検討を試みた.まず, 遡上期における稚魚の分布を全島的に調査したところ, 東西2地域では従来通り本亜種の生息が確認できたが, それらを隔てる南部や北部地域の河川では本亜種は全く出現せず, 沿岸海域を通じての東西間の仔稚魚の移動の証拠は得られなかった.次に, 両地域の集団から得た標本にっいて電気泳動分析を行ったところ, 調べた28遺伝子座のうち多型的な2遺伝子座で, 遺伝子頻度の顕著な差異 (それぞれp<0.001) が認められた.以上の結果は, 東西両集団は, 相互の間でほとんど交流のない, 相対的に独立したものであることを示唆する.本亜種の保護を考える際には, こうした奄美大島における遺伝的多様性を慎重に考慮することが重要であると考えられた.
著者
岡田 弥一郎
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.5, no.3-6, pp.174-174, 1957-02-25 (Released:2010-06-28)
著者
望岡 典隆
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.61, no.1, pp.33-35, 2014-04-25 (Released:2016-05-22)
著者
工藤 孝浩
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.58, no.1, pp.99-104, 2011 (Released:2014-03-07)
著者
亀甲 武志 岡本 晴夫 氏家 宗二 石崎 大介 臼杵 崇広 根本 守仁 三枝 仁 甲斐 嘉晃 藤岡 康弘
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.61, no.1, pp.1-8, 2014-04-25 (Released:2016-05-22)
被引用文献数
1 or 0

To clarify the reproductive ecology of the endangered cyprinid Honmoroko, Gnathopogon caerulescens, endemic to Lake Biwa, the occurrence of eggs in inlets, sex ratio and monthly changes in gonad somatic indices (GSI) were investigated in the Nishinoko lagoon, adjacent to Lake Biwa, from March to May, 2012. Eggs of Honmoroko were found on gravel and vegetation in two inlets, suggesting that not only the reed zone of Lake Biwa and its lagoons but also inlets of the lagoons are important spawning habitats of that species. The sex ratios of individuals collected in the two inlets were more malebiased (11.2–32.1 : 1) than that in the reed zone of the lagoon (1.5–2.7 : 1). The GSI of males gradually decreased as the breeding season progressed, those of females not showing any significant statistical changes, except for individuals collected around the reed zone and inlet in April. It was concluded that males remain in inlets and the reed zone during spawning, whereas females migrate to the inlets only for spawning, subsequently returning to the reed zone until the next spawning session.
著者
桑原 雅之
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.60, no.1, pp.63-67, 2013-04-25 (Released:2015-05-05)
被引用文献数
1 or 0
著者
桑原 雅之 井口 恵一朗
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.40, no.4, pp.495-497, 1994-02-15 (Released:2010-06-28)
被引用文献数
3 or 0
著者
岸野 底 米沢 俊彦
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.60, no.2, pp.91-101, 2013-11-05 (Released:2015-12-26)

The longitudinal distribution of Ryukyu-ayu Plecoglossus altivelis ryukyuensis in the Katoku River, a small stream on Amami-oshima Island, southern Japan, was observed from December 2003 to November 2004. The number of Ryukyu-ayu in pools was greater than in glides or riffles in each life history season [spawning (Nov. to Feb.), up stream migration (Mar. to May) and growth (Jun. to Oct.) seasons], an analysis by Spearman’s correlation coefficient by rank test indicating that such abundance in pools tended to be consistently greater in lower reaches. This suggests that large pools in lower reaches are an important habitat for Ryukyu-ayu in the Katoku River. Accordingly, for the future conservation of the lower reaches and creation of large pools may be a positive step of this endangered fish.
著者
石崎 大介 谷口 義則 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.59, no.1, pp.49-54, 2012-04-25 (Released:2014-05-16)

Brown trout Salmo trutta, a well-known game fish, has had considerable adverse effects worldwide on native aquatic organisms in waters to which it has been introduced. Although the establishment of brown trout and its impact on native biota have been frequently reported in Japan, such reports have been primarily limited to Hokkaido. In 2008 and 2009, 11 juvenile and 6 adult brown trout, including a mature female, were captured in the Odori Stream, Jinzu River system, central Japan, a mating pair of brown trout swimming near a redd also being observed in 2009. It is now considered that the species has become established, following an accidental introduction from a local hatchery in 2004 during a severe flood indicating that future possible introductions of this species must remain a concern, even in central Japan.