关键词: 长江口, 鱼卵, 仔稚鱼, DNA条形码, COI, 潮汐, Yangtze River estuary, ichthyoplankton, larvae and juveniles, DNA barcoding, COI, tide

Abstract: To clarify the relationship between species composition of ichthyoplankton and tides in the Yangtze River estuary，we set 2 survey stations, L1 and L4, respectively on July, 2017. The sample was collected continuously for 24 hours. A total of 19 fish eggs and 201 juveniles were collected at the L1 station and a total of 17 fish eggs and 92 juveniles were collected at the L4 station. We totally obtained 70 mtCOI, sequences 26 species were identified, of which 19 were identified to the species level, 1 was identified to the genus level, and 6 were identified to the level of the genus, the average genetic distance within the species is 0.007. The results of species diversity analysis based on DNA barcode showed that:There are 14 species at L1 station and 21 species at L4 station. Tide has a great influence on the abundance of ichthyoplankton in the Yangtze estuary, but has little to do with species composition. The abundance of inshore station decreases at flood tide and so does that of offshore station. Inshore station havs higher abundance than off-shore station, but offshore station has higher species richness. The results show the reliability of DNA barcode technology in the study of fish eggs and larvae diversity, and reveals the influence of tidal waves on the species composition of fish eggs and larvae in the Yangtze River estuary.