Widespread flooding from hurricanes Marco and Laura could impact crawfish production this coming season, but the extent of any damage will depend on whether crawfish producers are able to get the unwanted water off their fields in a timely manner.
When storm-related flood waters cover pond levees in July, August or September, crawfish have no choice but to get out of their burrows. Unfortunately, once they come out they usually die because of hot, stagnant water and predation by birds and other predators.
When crawfish ponds are flooded during the summer before egg-laying has begun, crawfish that manage to survive being flushed out of their burrows attempt to go back underground, either using an existing burrow or constructing a new one.
Several years ago, research at the LSU AgCenter’s Rice Research Station confirmed that female crawfish can survive being flushed from the ground several times and still go on to spawn in the Fall if they can get back into a burrow. But if flooding continues for a week or longer with hot temperatures, oxygen levels in the water drop to zero and crawfish are forced out onto the pond banks where they become easy prey.
A producer can suffer heavy losses of the mature crawfish that he or she was counting on to produce the next season’s babies.
What should crawfish farmers do if these storms cause widespread flooding? Do not hold the water. Ponds should be drained as soon as possible. This will help to eliminate predatory fish that often enter with flood waters.
One sunfish can eat the equivalent of a sack of crawfish over the course of the season, so fish control is an important consideration. Once fish have been eliminated, growers should put a couple of inches of water back on the field if they have planted rice as a forage.
In fields where rice has already been harvested, producers are encouraged to manage the rice re-growth but wait until early October to flood up. For ponds where rice could not be planted as a forage crop or ponds with natural vegetation, producers should still drain as soon as possible to get rid of fish.
As always, waiting to flood until temperatures have cooled off in mid-October makes the most sense economically.
Louisiana’s crawfish aquaculture industry has dealt with Hurricane impacts many times over the past 5 decades, and each year producers are more experienced and better prepared to deal with them. Hopefully Marco and Laura will not cause prolonged flooding and producers will see good reproduction this Fall.
If you have any questions, please give me or Dr. Greg Lutz a call and we will be happy to help.
Stay safe in the storms,
- Mark Shirley – 337-296-6864
- Dr. Greg Lutz – 225-223-0371