Study on the Population and Effect of Fish Passing Through the Fishway in Cao’e River Gate

Abstract

Abstract Fishway is one of the important ways to solve that gate dam obstructs fish migration. Through the monitoring and sampling of the right bank fishway of the Cao’e River Gate during May to November 2019, a total of 27 species of nektonic organisms were captured, totaling 2,926, belonging to 10 orders and 15 families, including mostly coilia ectenes, secondly minnow and others (crucian carp, bighead carp, silver carp, carp, and lateolabrax maculatus, etc.); the average species diversity index of nektonic organisms is 2.278, the average species richness index is 1.704, the average uniformity is 1.12, and the average dominance is 0.728. The data show that the effect of fish passing through fishways in different seasons, hydrological conditions, and weather conditions is very different. In general, the number of fish passing in spring and summer is much higher than that in autumn and winter. Of which, the number (individuals accounted for 91.41% of all) monitored in May, June, and July far exceeded that in other months. From May, the species and number of fish passing gradually increased, and by July, they reached their peak. Comparing the historical monitoring data in this region and the effects of fish passing through other typical fishways at home and abroad, the Cao’e River fishway provides a channel for the exchange of upstream and downstream fish of the gate, becoming an important channel to resolve the migration of blocked fish. It is recommended to strengthen the long-term monitoring and study of fishway, providing scientific basis for the collection of fish fry by opening the sluice gate, and also laying the foundation for further evaluation of the fish-passing effect of the sluice dam project in the Yangtze River Delta.