Wetlands’ Decline Fuels Unsustainable Harvests
Burgeoning Productivity Disguises Disaster in the Wetlands

He’s fished the waters of the Barataria Basin all his life, but in the past five years or so, says Eric Williamson, he just doesn’t catch fish like he used to.

The fish aren’t nearly as big or as plentiful as they’ve been in decades past. “I’m not sure what’s causing the decline,” Williamson says, “although it’s obvious that the habitat is changing. When I was a kid you could see solid marsh from the Leeville bridge to Grand Isle. Now, 30 years later, you look out at bits of broken marsh and a lot of open water. A change that dramatic has to affect the fish.”

The Barataria Basin may be suffering the effects of land loss that scientists have been predicting. As wetlands continue to disappear, every hunter and fisherman in the sportsman’s paradise may soon be sharing Williamson’s experience.

Of all the nicknames by which Louisiana is known — the Pelican State, the Bayou State, the Child of the Mississippi — the most popular throughout the years has been “The Sportsman’s Paradise.” Certainly to the state’s nearly 300,000 annual visitors who come to hunt and fish, the phrase is richly descriptive. It is so apt a moniker that the 2003 Louisiana Legislature passed a bill directing its inclusion on the state’s license plates.
Courtesy of Louisiana Office of Tourism

Boom Before Bust?

For decades the region’s size has hidden the effects of Louisiana’s coastal land loss from sportsmen’s notice: If there were no longer any speckled trout here, there were still plenty of them — and maybe more — over there. Paradoxically, wetland disintegration enhances marsh edge habitat. As the length of interface between land and water increases, populations of many species swell before the ecosystem collapses altogether.

Consider a healthy marsh one mile square. That marsh has four miles of edge habitat, where land and water intersect — prime territory for fish and reptiles, wading birds and waterfowl. Imagine a pipeline canal bisecting this square of marsh. Suddenly the amount of edge real estate is increased by two miles. With a 50 percent increase in edge habitat, marsh populations flourish.

But more edges — longer interfaces between land and water — cause more erosion. Water works its way among large chunks of the marsh and creates yet more edge that in turn supports larger marsh populations but causes yet more erosion, until the marsh becomes more water than land. Water bodies join together, edges vanish, habitat disappears, and the marsh-dependent fish and wildlife populations crash.

Dependent on marshes in its larval and juvenile stages, spotted sea trout is among the species that move into more open water as adults.
Courtesy of Louisiana Office of Tourism

Species Move In and Out as Conditions Change

“When wetlands disappear, different fish move into the area,” says Harry Blanchet, a specialist in marine fisheries with the Louisiana Department of Wildlife and Fisheries (LDWF). “As a marsh converts to open water, we lose the species that develop in the quiet lakes and tidal sloughs of a wetland — brown and white shrimp, blue crab, red drum, speckled trout. They are replaced by fish that live and grow in an open water column, such as anchovies, blue fish, lady fish and mackerel.”

“Ducks and geese are adaptable to a variety of marsh conditions,” says Larry Reynolds, waterfowl expert with LDWF. “They can thrive in freshwater or intermediate marshes, in wetlands with a land-water ratio of 10 to 90 percent. But the basis of the waterfowl food chain is marsh vegetation. As it washes away, the numbers of waterfowl that the Louisiana coast can support will plummet.”

Things Are Not Always as They Seem

The boom-before-bust model might lead to the expectation that hunting and fishing results improve in direct relationship to land loss, but records from the past five decades do not support such a correlation. Does this invalidate the theory? “No,” says Reynolds. “The information is not contradictory; it is our understanding of it that is incomplete.”

“There’s a lot of noise in the signal,” Blanchet says. “Naturally there are good years and bad years, with numerous factors influencing the fluctuation of wild populations. You might expect a deteriorating marsh to increase fisheries but see instead a decline due to an unusually long cold spell, or because storm damage to commercial fleets translates into fewer reports of landings.”

The circumstances of speckled trout in 2006 exemplify the complex influences interacting in a coastal ecosystem. “Very dry conditions have increased salinity in the marshes,” Blanchet says. “Speckled trout are spawning further up the estuary where it is easier for eggs and post-larvae to reach the marsh ponds and tidal sloughs that are ideal for their growth. The result should be a short-term increase in the trout population. But in the long term, high salinity will destroy marshes that are normally fresh or of intermediate salinity. When the marsh disappears, the trout that depend on the marsh disappear too.”

As young fish increase in size, they become less vulnerable to other fish, but more so to birds. At this stage they tend to migrate from their shallow marsh-edge habitats to deeper water.
Courtesy of Louisiana Office of Tourism

Habitats Respond to Restoration

Habitats change not only when wetlands convert to open water, but also when restoration techniques succeed and build new land or reverse saltwater intrusion.

“In the short run, some restoration activities may degrade waterfowl habitat,” Reynolds says. “Consolidating areas of broken marsh can produce a higher land-to-water ratio than ducks favor. But in the long run, healthy, resilient wetlands are crucial to a flourishing waterfowl population.”

“Changing conditions affect the distribution of fish,” says Blanchet, “and the intent of wetland restoration is to change conditions. Rebuilding healthy marshes can be disruptive, costly and inconvenient, but it’s fundamental to sustaining the sportsman’s paradise.”

Few people welcome changes to a familiar marsh or a favorite fishing hole. In the past, objections of sportsmen and other stakeholders have sometimes succeeded in restricting or delaying restoration projects. But following the devastating hurricanes of 2005, many people are beginning to see the enormity of the problem facing coastal Louisiana and to understand that giving up the way things are today may be necessary if paradise is to have any future at all.