The double hammerblows of hurricanes Katrina and Rita each ripped more than 100 square miles of marshland from the Louisiana coastline -- an ecosystem already in serious trouble as a result of erosion.

In both cases, the salty storm surge, nearly 30 feet in some areas, flooded prime freshwater and brackish marshes. As salt water poured into fragile wetlands, it killed marsh plants, fish and animals. When the floodwaters receded, people found plenty bass, redfish, catfish and many other species all over the place -- in their homes, cars, on the streets, parking lots and roofs!

Bass and other freshwater fish suffered more mortality than did saltwater species, as the briny surge poisoned formerly fresh areas. Some redfish and speckled trout, trapped in isolated pockets, died from a lack of oxygen.

"We had some mortality in areas," said Harry Blanchet, a marine biologist for the Louisiana Department of Wildlife and Fisheries. "In salt water we had a few sporadic kills where fish got trapped in isolated ponds and died from a lack of oxygen, but nothing like fresh water. Saltwater systems are more open. Saltwater fish have a good ability to hunker down. The tidal surge brought a lot of salty water far inshore, and it stayed inshore for a long time. People were catching redfish and speckled trout farther inshore than they normally would find them, in places like the Tickfaw River."

More troubling and potentially more permanent than the number of fish actually killed by the storm was the horrible damage that the habitat suffered. Salt water killed vegetation. Dying marsh grass left gaping holes in a coastal ecosystem already in peril. When the storm surge returned to the Gulf of Mexico, it carried huge chunks of marsh with it.

"Our long-term concern from the storms is what happened to the marshes themselves," Blanchet said. "We had a lot of marsh loss, but it's still unclear exactly how much we lost. Habitat is what supports the tremendous fishing that we have down here. Redfish are dependent on the brackish marsh habitats. If you don't have the brackish marshes, then you won't have the redfish resource that we had in the past. Assuming that the habitat survives, fish and wildlife can recover quickly, but the entire geography of the affected area changed."

Debris, including entire houses, barges and ships, clogged many bayous and channels, especially in Cameron, Plaquemines and St. Bernard parishes. New channels formed while some formerly deep bayous silted in, making them impassable. Islands in Breton Sound and other coastal bays disappeared. In other areas, islands appeared in places where solid marsh once stretched to the horizon.

Even in good times, Louisiana accounts for about 80 percent of the wetland loses in North America. The state, which contains more than 40 percent of the wetlands in the contiguous United States, normally loses between 20 to 30 square miles of coastal marsh per year. About every 30 minutes, about one football field of marshland disappears forever, Blanchet said.

In the southwestern part of the state, Rita left utter devastation in Cameron, Calcasieu and Vermilion parishes. Debris choked huge swaths of the Calcasieu and Sabine estuaries. However, much of the marsh remained relatively intact. Created by eons of backwash from the mushrooming plume of the Mississippi and Atchafalaya rivers, hard-packed sand beaches along the Cameron coast and hard-bottomed marshes can endure storms better than can alluvial delta splay marsh.