The newly constructed Russian avant-port "Bronka", located in the southwestern part of the Neva Bay at the southern tip of the Flood Protection Barrier of St. Petersburg, is designed for relief of the Main Port of St. Petersburg. In 2015 the 1st stage of construction was completed. The hydrotechnical works during the formation of the water area and the approach channel as well as at the underwater dumping site, have been annually increasing the content of suspended matter in water. Some depletion of fish fauna species composition and reduction of fish number and biomass was registered in a monitoring catch in the zone of construction impact. The damage caused during the construction works to aquatic biological resources has been compensated in full by releasing 336.9 thousand yearlings and fingerlings of the Ladoga trout. Also the new Nature Protected Area (NPA) "Southern Coast of the Neva Bay" was organized as a compensation action at the territory adjacent to the avant-port. Results of monitoring showed that the port construction has not influenced the species composition and structural and functional characteristics of the higher aquatic vegetation communities at the nearby coastal sites. The impact of construction works on higher plants was considered negligible at local scale, unaffecting the species composition and reversible. Field ornithological studies showed that species diversity and number of nesting birds at the territory of NPA "Southern Coast of the Neva Bay" did not change.