Louisiana’s Gulf Coast salt marshes support an unimaginable bounty of aquatic life, from shrimp to redfish to sharks, but their ability to do so literally shrinks every year, as the marsh on which these species depend vanishes.
Louisiana loses 25 to 35 square miles of coastal marsh each year. The reason for the recession is two-fold, says state Marine Fisheries Division biologist Harry Blanchet. The primary culprit goes back to 1927, when the U.S. Army Corps of Engineers installed levees along the Mississippi River to prevent floods. Before that, each spring the vast coastal marsh would receive a shot of freshwater, mud and nutrients washed in by the floodwaters. That would add a new layer of nutrients and material to the marsh grass and that would renew the marsh.
That hasn’t happened since the Great Depression, and the problem is exacerbated by the fact that the land, including that which holds up all that aquatic vegetation is sinking. Without new mass being pumped in, the marsh is being swallowed by the Gulf.
Another problem is the change in salinity caused by the building of roads, channels, highways, etc.
“Eighty-five to 95 percent of our fishery is dependent on marshes.”
The hope is that since the 2005 hurricanes, there’s been a new federal initiative to recognize the benefits of healthy coastal marshlands to serve as hurricane protection.
“We’re looking at seeing some funding coming for marshland production and we at Louisiana Fisheries are going to work to ensure that the Feds are designing these marshes for habitat—not just mud.”