Seasonal variations in diversity and abundance of surface ichthyoplankton in the northern South China Sea

Abstract

The objective of this study was to investigate the seasonal variations of ichthyoplankton diversity and abundance in the northern South China Sea based on the data collected during summer, winter and spring. In total, 95 taxa of larval fishes were identified. The greatest number of species was recorded in spring, followed by summer and winter. The number of species was distributed mainly in the coastal waters from the east of Leizhou Peninsula to the southeast of Hainan Island during the surveyed periods of summer and spring, but in the offshore waters during winter. The abundance of larval fish was lowest in winter, increased in spring, and reached the maximum in summer. High abundance of larval fish was generally restricted to coastal waters with the isobaths less than 50 m. Seasonal variations of larval fish richness, abundance and diversity index were significant (P<0.001). Carangidae was the most common and abundant taxon in summer and winter, while Sardinella sp., Thrissa mystax and Leiognathus sp. were dominant in spring. High diversity and abundance of larval fish might be attributed to increased temperature and coastal upwelling in spring and summer.