Abstract:
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 25.58×10
6, and the larvae runoff was 62.00×10
6. 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.