Status of early resources in Yujiang Jinling River section

We investigated and monitored the drifting eggs, larval fish supplementary group in Yujiang Jinling River section during March to September, 2012−2013. The results show that there were 21 species of eggs and larval fish in Jinling River, belonging to 4 orders and 8 families. The dominant species were Heniculter leucisculus (22.2%), Gobiidae (15.0%), Hemibarbus Bleeker (14.4%), Squalidus argentatus (7.2%) and Xenocypris argentea (5.5%). The average amount of eggs per year through the Jinling section was 1.29×10⁸, among which the drifting eggs accounted for 22.3% of the total amount of eggs. We failed to find four major Chinese carps and their eggs. The larval fish had appeared during May to August, whose highest density appeared in June, and the average monthly density of larval fish was 0.041 4 ind·m^–3. The density of larval fish and runoff had very significant positive correlation (P<0.01, n=270). The runoff and density of H.leucisculus, Hemibarbus Bleeker and S.argentatus also had significant positive correlation (P<0.05, n=270). Compared with the historical data, the function of Yujiang fish spawning field had changed a lot, and the spawning grounds of four major Chinese carps disappeared basically. Squaliobarbus curriculus, Cirrhinus molitorella, S.argentatus and other fish with small production of drifting eggs could be supplemented successfully, but their amount of resources is small. The annual fluctuation of runoff is an important factor affecting the early resource supplementation in the middle reaches of Yujiang River.