Based on four surveys of eggs and larvae in the Yangtze estuary in 2005 (April and November) and 2006
(April and September), combined with the historical data of the wetland in 1990 (September) and 1991 (March), we
analyzed seasonal changes in fish species composition and quantity of ichthyoplankton. Thirty-six species of egg and
larvae were collected and marine fish species were the highest represented ecological guild. Average fish species and
average abundance in spring were lower than in autumn for every survey. The total number of eggs in brackish water was
higher than in fresh water, but the total number of larvae and juveniles in brackish water was lower. The abundance of
eggs and larvae during from 2005 to 2006 in both spring and autumn was higher compared to those from 1990 to 1991.
Obvious differences in species composition in September between 1990 and 2006 were found, especially for
and Neosalanx taihuensis
. Fish species composition and quantity within the ichthyoplankton
community has obviously changed in the Yangtze estuary over the last 20 years.