Coastal Louisiana has lost an average of 34 square miles of primarily marsh land per year for the last 50 years. From 1932 -2000 coastal Louisiana lost 1900 square miles – highlighted in red on map. Map: U.S. Geological Survey
by Mark Evans/Louisiana Seafood News
The series of hurricanes that savaged Louisiana’s coast in recent years is not only reshaping how the state responds to them, but also how it combats coastal erosion left in their wakes.
Erosion is destructive on several levels, it harms Louisiana’s fisheries – and consequently, its seafood industry. Photo: CPRA
Since the 1930s, the state has lost 1,880 square miles to coastal erosion, according to Louisiana’s Coastal Protection and Restoration Authority (CPRA). That area is equivalent of losing the landmass of New York City every 13 years
This erosion is destructive on several levels. The most obvious is devastation to coastal communities. It also harms Louisiana’s fisheries – and consequently, its seafood industry – of valuable nursery grounds for finfish, shellfish and other wildlife
Beyond that, ongoing erosion threatens a culture around which many of the state’s long-held traditions were built, such as:
- Its rich culinary heritage that often centers on seafood.
- Louisiana’s reputation as a “sportsman’s paradise” for fishing and hunting.
- Confluence of its Creole and Cajun cultures in the bayous and swamps of coastal areas.
Louisiana Sea Grant marine agent Mark Shirley said coastal erosion is caused – or made worse – by a number of factors. They include land subsidence, rising sea levels, climate change, saltwater intrusion, the cutting of new transportation channels and confinement of the Mississippi River.
Gulf Knocking at Parishes’ Doors
Louisiana’s coast was created over thousands of years by the sediments of the Mississippi River, he said. The confinement of the river means those sediments are no longer available to replenish land that compacts and subsides or is lost to erosion.
The Gulf of Mexico already is knocking at the doors of Terrebonne, Plaquemines and Lafourche parishes.
Jerome Zeringue, CPRA executive director, oversees an agency charged with developing, implementing and enforcing a comprehensive coastal protection and restoration master plan for the 397-mile Louisiana coastline. Photo: CPRA
Jerome Zeringue, CPRA executive director, oversees an agency created after hurricanes Katrina and Rita. It’s charged with developing, implementing and enforcing a comprehensive coastal protection and restoration master plan for the 397-mile Louisiana coastline.
Included in this charge are efforts to combat or minimize the impact of coastal land loss—or even reverse it wherever possible.
Just consider: Louisiana has 40 percent of the nation’s wetlands. Yet, it’s experiencing 80 percent of the total wetland loss in the United States, Zeringue pointed out.
Coastal erosion and wetland loss are significant threats to the state’s seafood industry.
Habitat Disappears with Coastline
Every 38 minutes, the state loses a parcel of wetlands the size of a football field, he said. These same wetlands provide critical nursery habitat for fish and shellfish that form the basis for not only Louisiana’s fisheries and seafood industry, but also those of the entire Gulf region.
“A significant proportion of the fish throughout all of the Gulf of Mexico spend time in the nursery habitat found along the Louisiana coast,” said Louisiana Sea Grant marine agent Mark Shirley (holding fish). “When you lose that coastline, you lose that habitat that provides the basis for the region’s fisheries to grow and survive.” Photo: Mark Shirley
“A significant proportion of the fish throughout all of the Gulf of Mexico spend time in the nursery habitat found along the Louisiana coast,” he said. “When you lose that coastline, you lose that habitat that provides the basis for the region’s fisheries to grow and survive.”
If the wetland loss were to continue unchecked, Shirley said, it would eventually lead to a decline in seafood production. The organic material produced by wetlands serves as food for baby fish, crab and other invertebrates that form the bottom of many aquatic food chains.
“Our estuaries, with all of their small bayous and marsh grasses, create an interface with seawater,” he said. “That edge effect is a vital aspect of the productivity of those estuaries.”
That edge effect is lost as marshes are lost to erosion and become open water bays, he said. Some experts anticipate that Louisiana will eventually start to see a decline in seafood production as the state loses increasingly larger areas of marshland.
Research suggests that the peak of fisheries production occurred in the 1970s and 1980s and that a plateau was hit in the 1990s, he said. Only time will tell whether that comes to pass.
Right now, Shirley said, the state is not yet seeing a decline in seafood production due to erosion and wetland loss. Even so, he said, the Gulf is coming.
$50B to Restore, Protect Coast
Within the next 100 to 200 years, he predicts many of Louisiana’s coastal communities will have to move inland by as much as 100 miles.
“I don’t think anyone thinks we can make the Louisiana coastline like it was in 1940 or 1950 – even with a couple-billion-dollar-price tag,” he said
In May, the Louisiana Legislature unanimously approved the state’s 2012 Coastal Master Plan. The plan calls for $50 billion in coastal restoration and protection projects over the next 50 years. Photo: CPRA
“But, we can spend some money and gain some number of years of seafood productivity and buy time for some of our coastal communities. In many cases, that investment is worth it.
In May, the Louisiana Legislature unanimously approved the state’s 2012 Coastal Master Plan. The plan calls for $50 billion in coastal restoration and protection projects over the next 50 years.
It identifies and prioritizes projects based on their ability to have the greatest long-term impact on the Louisiana coast. The goal is to increase flood protection for communities, save and build land, marsh and barrier islands, and create a sustainable coast.
The plan addresses immediate needs, such as providing protection to communities threatened by erosion. It also lays the foundation for long-term, sustainable efforts that include restoring marshes.
By implementing the plan, Zeringue said the state hopes to be building more wetlands than it is losing within 30 years.
“The plan is an investment in our future,” he said. “We want to create a sustainable coast for generations to come.”
Within the next 100 to 200 years, many of Louisiana’s coastal communities will have to move inland by as much as 100 miles. Photo: Ed Lallo/Louisiana Seafood News
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