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A Great Blue Heron flies over a row of crawfish traps in a  pond off of La. 13 just north of Crowley.

It’s almost time to flood crawfish ponds and get started on another season, said Mark Shirley, aquaculture specialist with the LSU AgCenter and Louisiana Sea Grant.

But he recommended farmers wait until temperatures moderate a bit before beginning to flood. 

“When the lows at night dip into the 60s and the highs are no longer in the 90s, then it’s time to raise the water level and get the brood stock out of the burrows to drop their young and populate the pond,” he said. “This usually happens in the first couple of weeks in October.”

Shirley added that “flood up” means putting a deep enough flood to saturate the levees to the height where the brood stock buried in at the end of last season. That may be 12, 14 or 16 inches of water across the pond.

If rice was planted solely for crawfish forage or if a farmer is dealing with a ratoon crop, the pond has probably been flooded with 2-4 inches of water since sometime in August.

“In general, a light flood like that does not stimulate any large numbers of crawfish to emerge from their burrows,” Shirley said.

Not until the levees get saturated, either from raising the water level or a big rain, do the crawfish dig out of their burrow and enter the pond. The water quality and vegetation that the crawfish find when they emerge will determine their survival and growth, he said.

Warm water and lots of dead or dying vegetation will cause the dissolved oxygen to drop to near zero, and any surviving crawfish will be so stressed that their growth will be delayed and stunted, Shirley said.  Pond management will determine if it has a healthy habitat for crawfish or if it has created a dead zone.

“It all depends on the amount of decaying vegetation in the water," he said. "Just a little rotting rice straw or dead weeds will rapidly consume all the oxygen, and all the pumping in the world cannot overcome the oxygen demand.”

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