Salt Water Intrusion Threatens Crawfish Farmers

Salt water intrusion is dangerous to the cultivation of crawfish, a fresh water species.

It’s the perfect storm for southwest Louisiana crawfish farmers.

An extended drought, damaged lock gates within the Intracoastal Waterway and breaches from a bayou have all contributed to salt water intrusion from the Gulf into the 700-mile freshwater Mermentau Basin. Unless there is significant rainfall this winter, Basin crawfish farmers may be in serious trouble, which is why Vermilion Parish declared an emergency in late November.

“It’s a big problem for Vermilion Parish,” said Wayne Touchet, Vermilion Parish Police Jury President.

Salt water is entering lower Vermilion, lower Jefferson Davis and the southeastern sections of Cameron and Calcasieu parishes, said Mark Shirley, an aquaculture specialist with LSU AgCenter in Abbeville. Salt water intrusion is dangerous to the cultivation of crawfish, a fresh water species.

The causes of the salt water encroachment are many. The drought that has lingered in southwest Louisiana means less rainwater to flush out the fields. With fresh water in the crawfish ponds evaporating without rainfall to replace it, and salt water leaking in, the soil’s salinity levels go up, Shirley said.

“We’re still in a drought that has been going on for two years,” he said.

The salt water leaks have been occurring along breaches on Freshwater Bayou that connects the freshwater marshes to the Gulf of Mexico. In late September, an oil barge damaged the Leland Bowman Lock near Intracoastal City, which is now allowing salt water into the Basin from that channel. The Corps of Engineers is estimating February or March, 2012, before the locks are fixed.

“It is kinda complicated because it’s not just one thing causing the problems,” Shirley explained.

Crawfish can tolerate small amounts of salt water, Shirley said, so it’s likely the spring crops will be spared. Significant rainfall this winter will help flush the salt out of the freshwater marshes.

If winter doesn’t bring adequate rain, however, future years may be bleak.

Meanwhile, Touchet, state leaders and farmers are developing plans to divert Red River water from the middle of the state should a drought occur again.

“We want to be ahead of the game,” he said. “Diversion will definitely solve our problems.”

For now, however, it’s a battle against time to fix the lock gates and the bayou and channel breaches.

“It’s going to take a huge effort,” Touchet said, “and a lot of rain and prayers.”

Tags: crawfish, Featured, Gulf of Mexico, Intracoastal Waterway, Mark Shirley, Mermentau Basin, saltwater intrusion, Vermilion Parish, Wayne Touchet