沙柳河青海湖裸鲤早期资源发生量及时空分布

为了掌握青海湖裸鲤(Gymnocypris przewalksii)资源补充状况, 于2019年5月26日至9月2日逐日在青海湖第二大支流沙柳河开展了青海湖裸鲤早期资源丰度时空变化特征的调查研究, 共采集青海湖裸鲤鱼卵3386粒, 仔鱼4690尾。调查发现, 亲鱼自5月底开始洄游, 鱼卵6月初出现, 6月底至7月初达到高峰, 随后逐渐下降, 至8月中旬基本消失。仔鱼数量自7月初呈波动式上升, 8月达到高峰, 9月初逐渐消失。经估算, 沙柳河鱼卵径流量为25.58×106粒, 仔鱼径流量为62.00×106尾。鱼卵仔鱼空间分布为从河口往上丰度依次递减, 断面水平分布为右岸>左岸>中心。Kruskal-Wallis检验表明, 昼夜鱼卵丰度存在显著差异(P<0.05); 昼夜仔鱼丰度存在极显著性差异(P<0.01), 鱼卵仔鱼漂流高峰期均集中在夜间。鱼卵丰度与流速呈显著正相关(P<0.05), 仔鱼丰度与流速呈极显著正相关(P<0.01), 与径流量日上涨率呈极显著正相关(P<0.01)。研究报道了沙柳河青海湖裸鲤早期资源现状, 填补了该水域青海湖裸鲤早期资源研究的空缺, 为青海湖裸鲤上溯亲本资源量和入湖幼鱼资源量估算提供了数据支撑, 可为青海湖裸鲤资源管理与保护提供科学依据。

THE SPATIAL AND TEMPORAL DISTRIBUTION IN EARLY LIFE HISTORY STAGES OF GYMNOCYPRIS PRZEWALSKII IN SHALIU RIVER

Gymnocypris przewalskii is a typical plateau cold-water fish with saline-alkali tolerance,and the only aquatic economic animal in Qinghai Lake.It is the core of the entire ecosystem of Qinghai Lake that was once endangered,which is gradually recovering.To investigate the spatiotemporal variation characteristics of eggs and larvae of G.przewalskii in the Shaliu River,the second largest tributary of Qinghai Lake,a total of 3386 eggs and 4690 larvae of G.przewalskii were collected from 26 May to 2 September,2019.The results indicated that the parents fish began to migrate at the end of May,and the eggs appeared in early June.The egg production peaked from late June to early July,then gradually decreased,and basically disappeared in mid-August.The number of eggs peaked in July,tapered off in mid-August,and then disappeared.The number of larvae increased from early July,peaked in August and gradually disappeared in early September.It was estimated that the eggs runoff of the Shaliu River was 25.58×10⁶,and the larvae runoff was 62.00×10⁶.The spatial distribution of eggs seedlings was that the abundance decreased successively from the estuary upwards,and the horizontal distribution of cross section was the center>on the right bank and>on the left bank.Kruskal-wallis test showed that there was a significant difference in eggs abundance between day and night(P<0.05);the abundance of larvae between day and night was significantly different(P<0.01);the floating peak of eggs seedlings were all concentrated at night.There was a significant positive correlation between eggs abundance and flow rate(P<0.05),and the abundance of larvae was significantly positively correlated with flow rate(P<0.01),which was significantly positively correlated with the daily increase rate of runoff(P<0.01).This first study filled in the gap of the abundance of eggs and larvae of G.przewalskii in this water area to provide basic data for estimating the amount of upstream parents and juvenile fish entering Qinghai Lake of G.przewalskii and scientific basis for protecting the resources management and protection of G.przewalskii.