长江上游江津江段鱼类早期资源时空分布特征研究

于2009年5—7月对长江上游江津江段卵苗的时空分布进行了调查。结果显示:在5月14日、6月3日及6月9日前后该江段有卵苗汛发生,卵苗的平均密度为9.36 ind/100 m3,最大密度为37.73 ind/100 m3;经威氏符号秩次检验,卵苗密度的昼夜分布没有显著性差异(P>0.05);卵苗密度垂直分布没有显著性差异(P>0.05);在水平分布上,南岸和北岸之间的卵苗密度没有显著性差异(P>0.05),两岸和江中间的卵苗密度均存在极显著性差异(P<0.01)。

Spatial and temporal distribution of larval resources of fishes in the upper reaches of Yangtze River

For the purpose of spatial distribution of drifting eggs and larvae at Jiangjin cross-section in the upper reaches of Yangtze River,the surveys were carried out from May to July in 2009.The results showed that there were drifting eggs and larvae flood around May 14,June 3 and June 9,the average density for drifting eggs and larvae was 9.36 ind/100 m3,the maximum density was 37.73 ind/100 m3;Wilcoxon signed rank test indicated no significant difference in distribution between day and night for drifting eggs and larvae(P>0.05);it was the same in the vertical distribution density for drifting eggs and larvae(P>0.05);besides,there was no significant difference in horizontal distribution density between north bank and south bank(P>0.05).However,there were dramatic differences in horizontal distribution density between two banks and middle area(P<0.01).