The ecological study of fish larvae in the Yangtze River Estuary and adjacent waters

Abstract:

The categories composition and abundance distribution of fish larvae in the Yangtze River Estuary and vicinity waters were analyzed based on data from four seasonal surveys at 504 sampling stations during 2006 to 2007. Eighty-two species of fish larvae were collected, belonging to 16 orders, 48 families. Among them, Perciformes was the most diverse group, with 34 species from 21 families. Scorpaeniformes, including 3 families, 10 species, and Clupeiformes, including 5 families, 8 species, were the next diverse fauna. There was clearly seasonal and spatial variation of theabundance of fish larvae and the number of species of fish larvae. The seasonal abundance of fish larvae was listed as summer (185 ind/100m³) > spring (37 ind/100m³) > autumn (6 ind/100m³) > winter (1 ind/100m³), and they mainly centered in spring and summer. The average abundance of fish larvae was higher in summer than in spring and the distribution areas were more to the west in summer. The number of the fish larvae species was in the order of summer (39 species) > spring (38 species) > autumn (25 species) > winter (16 species). The dominant species were Engraulis japonicas, Coiliamystus, Benthosemapterotum in spring, summer and autumn respectively. Multivariate statistical analysis showed that in spring, the distribution of most species of ichthyoplankton was controlled by depth of water and surface salinity. While in summer, most species preferred the estuarine and coastal waters, which was characterized by higher chlorophyll a concentration and surface temperature.