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 G