Physical and biological impact on marine benthic Polychaetes due to dredging in the Mormugao harbour, Goa and its restoration after dredging

Abstract

Recolonization of benthos following dredging operations was studied in Mormugao Port Trust Harbour, Goa Six stations were fixed for sampling within the radius of the dredging site Three samples each were collected during dredging and after dredging The proportion of gravel in the sediment of the dredged site increased after-dredging, while that of organic matter decreased The impact on community was estimated at species level, using both univariate and multivariate analyses Maximum negative effect was observed during dredging where a reduction by 60-70% on macrofauna was evident Within six weeks after dredging the density of the polychaete Clymene annadalei increased in the dredging site, while typical 'opportunistic' species such as Capitella capitatu was not favoured by dredging Favourable condition for resettlement of benthic communities is probably available in about four months.