Riverine life history of the amphidromous goby Sicyopterus japonicus (G obiidae : Sicvdiinae) in the Ota River, Wakayama, Japan
Riverine life history of the amphidromous goby Sicyopterus japonicus (G obiidae : Sicvdiinae) in the Ota River, Wakayama, Japan
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日本和歌山太田河双性性虾虎鱼 Sicyopterus japonicus（Gobiidae：Sicvdiinae）的河流生活史
DOI：
10.1007/s10641-012-0055-9
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发表时间：
2013
影响因子：
1.4
通讯作者：
K. TSUKAMOTO
中科院分区：
文献类型：
--
作者：
IIDA;M.;S. WATANABE;K. TSUKAMOTO
为了了解日本和歌山大田河中无洄游虾虎鱼的河流生活史，对该鱼进行了研究。它们主要分布在河口上游3 ~ 23 km处，且中游丰度高于上下游。在冬季，急流中没有观察到鱼类，这表明栖息地的季节性变化。体长范围为24至120 mm SL。雌、雄的年龄均为1 ~ 6岁，且雄的渐近体长大于雌。条件因子在7月和11月出现两个高峰，与产卵期和越冬准备期相对应。性腺体细胞指数在夏季增加，在8月达到高峰，表明夏季产卵季节，证实了收集的新孵化的幼虫迁移下游。直径为0.5mm的卵附着在石头上，初孵幼虫作下沉和向上游动的连续垂直运动，每次运动的距离在淡水中比在海水中长。初孵仔鱼主要在8月份夜间（19：00-24：00）采集。这些幼虫非常小（平均值：1.4 mm TL），有卵黄囊，没有眼睛色素沉着。冬季的低温可能是产卵和补充季节以及该物种活动季节性变化的重要决定因素，该物种生活在比该亚科所有其他物种高得多的纬度。
To understand the riverine life history of the amphidromous goby,Sicyopterus japonicus, studies were conducted in the Ota River, Wakayama, Japan. They were distributed from 3 to 23 km upstream from the river mouth, and abundance was higher in the middle reaches than in the upper and lower reaches. Fish were not observed in rapids during winter, suggesting a seasonal change of habitat. Body length ranged from 24 to 120 mm SL. Both females and males ranged from 1 to 6 years old, and males had larger asymptotic length than females. Condition factor showed two peaks in July and November, which appeared to correspond to the spawning season and preparation for over wintering. Gonad somatic index increased in summer with a peak in August indicating a summertime spawning season that was confirmed by collections of the newly hatched larvae migrating downstream. Eggs of 0.5 mm diameter were attached to stones and newly hatched larvae made continuous vertical movements of sinking and upward swimming and the distance of each movement was longer in freshwater than in seawater. The newly hatched larvae were collected at nighttime (19:00–24:00) mainly in August. Those larvae were very small (mean: 1.4 mm TL) with a yolk sac and no eye pigmentation. Low wintertime temperatures are likely an important determinant of the spawning and recruitment seasons and seasonal changes of activity of this species that lives at much higher latitudes than all other species of the subfamily.