| In order to assess the impacts of dredging activities on early life of fishes in the channel zones of Yangshan harbor, a 48 h acute toxicity test on the embryo and larva of Acanthopagrus schlegelii and larva of Larmichthys crocea was conducted using the eluates from dredged sediments from three sites of dredging zones. Chemical analyses showed that water quality of eluates from the site 3 was the best, but the worst from the site 2. The eluates from all three sites had no significant influences on hatching rates of A. schlegelii embryos, but showed acute toxicity to the larvas. In the group with highest concentrations, the 48 h mortality of A. schlegelii larvas was 14.76%, 25.46%, and 29.81%, and that of L. crocea larvas was 20%, 20%, and 40% for the site 3, 1, and 2, respectively. In the middle concentration group, the 48h mortality of A. schlegelii larvas was 9.45%, 15.41%, and 22.38%, and that of L. crocea larvas was 15%, 20%, and 20% for the site 3, 1 and 2, respectively. The mortality was slightly higher for L. crocea larvas than A. schlegelii larvas, and was significantly positively correlated with eluate concentrations. The results indicate dredged sediments from the site 2 has the highest toxicity to fishes and the least from the site 3. |
