Oyster beds have become less productive and many freshwater species of fish have been driven out of the area due to salinity changes. Residents of St. Bernard and Plaquemines Parishes fear for their safety in the event of a large storm surge during a hurricane or other tropical storm. Wetlands act as a natural sponge to absorb rising waters. Without wetlands, storm surge cannot be slowed and water can directly enter St. Bernard, Plaquemines, Orleans, and Jefferson Parishes, causing massive flooding, property damage, and even death. Tidal action and ship traffic have also caused wetland loss.
Large ships create a suction that pulls water out of adjacent marshes.
After the ship passes, the wave it has created forces water back into the marshes. This crashing wave puts tremendous force on the banks of wetlands causing them to erode. Tidal action is another cause of wetland erosion. Linked to the Gulf of Mexico, the MRGO experiences tidal fluctuations. Due to friction in the wetlands, tidal changes are very severe which causes wetlands to erode.