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Reproduction of Japanese anchovy in the Kuroshio Extension and transition waters.

日本鳀鱼在黑潮延伸区和过渡水域的繁殖。

基本信息

批准号：
09660195
负责人：
AOKI Ichiro
金额：
$ 1.6万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09660195/
关键词：
Japanese anchovy Spawning Fish larvae Growth Kuroshio Extension Transition region

项目摘要

Spawning frequency, which is represented by the fraction of females with postovulatory follicles, and batch fecundity were higher in offshore populations than in coastal ones. This suggests that anchovy in offshore waters adopt a reproductive strategy in which they assign more energy to reproduction and produce more eggs in a certain period than those in coastal waters. Anchovy spawn in the temperature range of 8-22ﾟC with batch fecundity varied in proportion to temperature. This enables anchovy to utilize offshore extensive areas as their spawning grounds. On the other hand, the analysis of mtDNA showed that several anchovy populations off the coastsfrom northern and western Kyushu to Honshu-Hokkaido were not distinguished genetically.Anchovy larvae and juveniles were distributed widely as far offshore as 160 deg.E.They migrated offshore, growing at a rate similar to those in coastal waters. The daily mortality rate decreased with growth, being lowest for larger Jarvae offshore. Stomach content analysis revealed that occurrence of empty stomach was very high in larvae <30mm SL and reduced for juveniles> 35mm SL.Food organisms were predominated by copepods. With increase in fish size, occurrence of warm water species of copepods and amphipods increased. It was suggested that juveniles > 55mm SL feed on conspecific small larvae.

产卵频率，这是代表的女性与排卵后卵泡的比例，和批量繁殖力在近海人群比在沿海的。这表明，近海沃茨的鱼采取了一种生殖策略，即在一定时期内分配更多的能量进行生殖，比沿海沃茨的鱼产生更多的卵。鳀鱼在8-22 ℃的温度范围内产卵，批量繁殖力随温度的变化而变化。这使鱼能够利用近海广阔的地区作为其产卵场。另一方面，线粒体DNA分析表明，从九州北方和西部到本州-北海道沿岸的几个鳀鱼种群在遗传上没有区别，鳀鱼仔、稚鱼广泛分布于160 ° E的近海，它们向近海迁移，生长速度与沿海沃茨相似。每日死亡率随着生长而下降，对于较大的Jarvae近海来说是最低的。胃内容物分析表明，35 mm SL的幼虫空腹发生率很高<30mm SL and reduced for juveniles>，食物生物以桡足类为主。随着鱼体大小的增加，桡足类和端足类的暖水性物种的出现增加。体长> 55 mm的幼鱼可能以同类的小幼鱼为食。