著者

向井 貴彦 Padhi Abinash 臼杵 崇広 山本 大輔 加納 光樹 萩原 富司 榎本 昌宏 松崎 慎一郎

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

vol.63, no.2, pp.81-87, 2016-11-05 (Released:2018-06-01)

参考文献数

20

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The North American channel catfish Ictalurus punctatus, an invasive freshwater fish introduced to Japan for aquaculture in the 1970s, has become established in several rivers and lakes, with subsequent detrimental effects on local fisheries and other freshwater fauna. The origin and invasive distribution of channel catfish in Japan was assessed from the geographical distribution of mtDNA haplotypes of channel catfish populations, utilizing partial (412 bp) nucleotide sequences of the mtDNA control region from 174 individuals collected from 7 localities. A total of 12 haplotypes (J01–J12) were found in Japanese freshwater systems. Populations in eastern Japan (Fukushima and Ibaraki Prefectures) and a fishing pond in Aichi Prefecture were characterized by many haplotypes, shared among those localities. However, the haplotype compositions of populations in western Japan (Yahagi River, Aichi Prefecture and Lake Biwa water system, Shiga Prefecture) differed from the former and also from each other. A phylogenetic analysis using Japanese (nonindigenous), Chinese (non-indigenous) and United States (indigenous) haplotypes indicated that all of the Asian haplotypes were included in "Lineage VI," distributed over a wide area of the United States, confirming that lineage as the primary source of introduced Asian populations. However, the introduction of channel catfish into Japan occurred on at least three occasions (in eastern Japan, Yahagi River and Lake Biwa water system).

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)

参考文献数

24

被引用文献数

1

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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.