The study on the conservation and management of ayu, Plecoglossus altivelis, populations in the Kasumigaura Lake system, Ibaraki Prefecture, Japan.

日本茨城县霞浦湖水系香鱼、Plecoglossus altivelis 种群的保护和管理研究。

• 批准号: 13660191
• 负责人: IDA Hitoshi
• 金额: $ 1.79万
• 依托单位: Kitasato University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13660191/
• 关键词: ayu; growth; land locked; DNA; otholith; food selectivity; gene diversity; gill taker length; 成長率依存的死亡; 霞ヶ浦; 日周輪; 陸封化; アロザイム; EPMA; 餌料生物

Ayu, Plecoglossus altivelis recently proliferated in the Kasumigaura Lake was studied. From the allozyme analysis the population was identified as an amphidromous type with the neighboring rivers populations but making slightly different sabcluster. By the electron microplobe analysis(EPMA), Sr/Ca ratio in otolith was measured, and was found that the population of the lake system did not have the stage in the coastal area. In the juvenile stage, nauplius of copepods with other zooplankton were found to be the main food item, but in the later stage in the lake, cyclopoids and then mysids dominated as the main food items. After entering flowing Koise River, Ayu shifted food item to benthic algae with some addition of aquatic insects. From the analysis of daily growth ring on the otolith, the modes of growth of individuals from both the lake system and the neighboring rivers were compared. Because of extreme lowering of the water temperature of the lake system in winter, the growth of Ayu was scanted and the stunted growth resulted making a transparent zone without daily rings on the otolith. But the stunted growth was compensated by the faster growth by warmer water temperature in late spring to early summer and the body size in summer was not less than that of the amphidromous neighboring river groups. Estimation of the spawning date from the daily rugs on the otolith was made using individuals collected by January, thus lacking transparent zone on the otolith, the spawning season was determined as October to November. The growth rates an tie were compared and was found that those after the wintering was higher than those before the wiring. Analysis of mitochondria and genomic DNA suggested the genetic diversity of the Ayu population of the lake system was similar with that of the neighboring river population and there was no trace of the bottle neck effect on the population.

对霞浦湖新近增殖的香鱼进行了研究。等位酶分析表明，该种群与邻近河流种群为两游型，但聚类结果略有不同。通过电子探针分析（EPMA），测量了耳石中Sr/Ca比，发现湖泊系统的种群在沿海地区不存在阶段性。在幼鱼阶段，桡足类无节幼体和其他浮游动物是主要的食物，但在湖泊的后期，剑水蚤和糠虾的主要食物项目占主导地位。进入流动的小濑川后，阿玉将食物转移到了底栖藻类，并加入了一些水生昆虫。通过对耳石日生长轮的分析，比较了湖泊系统和邻近河流中个体的生长方式。由于冬季湖盆水温极低，使阿玉鱼的生长受到限制，耳石上形成一个无日环的透明带。但春末夏初水温升高使其生长速度加快，弥补了其生长的不足，夏季个体大小不小于邻近的无潮性河流群。根据1月份采集的个体耳石上的日纹推算产卵期，由于耳石上缺乏透明带，产卵期定为10 ~ 11月。结果表明，越冬后的生长速率高于结网前。线粒体和基因组DNA分析表明，湖泊系统阿鱼种群的遗传多样性与邻近河流种群相似，不存在瓶颈效应。

项目成果

Kaewsangk K. et al.: "Clarification of the origin of landlocked ayu, Plecoglossus altivelis, populations in the Kasumigaura Lake system, Ibaraki Prefecture, Japan"Fisheries Sciences. 67(6). 1175-1177 (2001)

Kaewsangk K. 等人：“阐明日本茨城县霞浦湖系统中内陆香鱼、Plecoglossus altivelis 种群的起源”渔业科学。

Kaewsangk, K., K.Hayashizaki, T.Asahida, T.Nemoto, H.Ida: "Clarification of the origin of landlocked ayu, Plecoglossus altivelis, populations in the Kasumigaura Lake System, Ibaraki Prefecture, Japan."Fisheries Science. 67. 1175-1177 (2001)

Kaewsangk, K.、K.Hayashizaki、T.Asahida、T.Nemoto、H.Ida：“阐明日本茨城县霞浦湖系统内陆香鱼、Plecoglossus altivelis 种群的起源。”渔业科学。

Kaewsangk, K., K.Hayashizaki, T.Asahida, H.Ida: "Difference in number of comb-like tooth plates in amphidromous and landlocked populations of the ayu Plecoglossus altivelis."Fisheries Science. 67. 752-754 (2001)

Kaewsangk, K.、K.Hayashizaki、T.Asahida、H.Ida：“香鱼 Plecoglossus altivelis 的两栖种群和内陆种群梳状齿板数量的差异。”渔业科学。

根本隆夫, 林崎健一, Krittikar Kaewsangk, 朝日田卓, 井田齊, 猿渡敏郎: "アロザイム分析からみた霞ヶ浦水系におけるアユの由来"茨城県内水面水産試験場調査研究報告. 38. 60-63 (2003)

Takao Nemoto、Kenichi Hayashizaki、Krittikar Kaewsangk、Takashi Asahida、Satoshi Ida、Toshiro Saruwatari：“从同种酶分析的角度分析霞浦水系香鱼的起源”茨城县内河渔业实验站调查研究报告38。60-。 63（2003）

Nemoto, T., K.Hayashizaki, Krittikar Kaewsangk, T.Asahida, H.Ida, T.Saruwatari: "The origin of ayu in the Kasumigaura Lake system deduced from allozyme analysis."Bulletin of Ibaraki prefectural freshwater fisheries experimental station. 38. 60-63 (2003)

Nemoto, T., K.Hayashizaki, Krittikar Kaewsangk, T.Asahida, H.Ida, T.Saruwatari：“通过等位酶分析推导出霞浦湖水系香鱼的起源。”茨城县淡水渔业实验站通报。