Impact assessment of dredging on fish eggs and larvae: A case study in Caotan, South China

Abstract

Dredging can lead to an increase in suspended sediment concentration, which poses a threat to the survival of fish eggs and larvae.To assess the impact of dredging on fish eggs and larvae, Caotan Fishing Port in south China was chosen as a case in this paper. The threat to the survival of fish eggs and larvae, i.e. the increased suspended sediment concentrations, is identified through analyzing pollution sources in dredging operations; the number and species of fish eggs and larvae were obtained through on-site investigations; the concentration and influence range of suspended sediments are calculated by pollutant diffusion equations; the loss of fish eggs and larvae caused by suspended sediment during dredging is evaluated according to Technical Regulations for the Impact Assessment of Construction Projects on Marine Biological Resources (SC/T 9110-2007) in this paper. It can be preliminarily concluded that the suspended sediments produced during dredging and backfilling have an impact on the survival of fish eggs and larvae, and will reduce their quantity. Currently, loss analysis methods are based on empirical formulas, and more accurate quantitative analysis needs to be further studied.