Crawfish may spend a good part of their life in water, but flooding at the wrong time could affect reproduction and survival. One of the keys to the 2017 season will be how fast producers are able to pump recent floodwaters, along with accompanying predacious fish, off their ponds.
“We really won’t know the extent of damage until we get into the harvest season later this winter,” LSU AgCenter and Louisiana Sea Grant aquaculture and coastal resources specialist Mark Shirley wrote in a recent newsletter to crawfish producers.
Crawfish typically spend summers sealed in burrows along pond levees. At the same time growers are either cultivating this year’s rice crop or planting forage for crawfish.
Between late August and early December, female crawfish lay eggs, which are carried under tails in the sealed burrows.
The female typically doesn’t leave the burrow until a good, heavy fall rain signals to her.
But when ponds are flooded in August, the female has no choice but to leave and face hot, stagnant water as well as predation from birds, fish and other animals.
Surviving crawfish will try to return to burrows or dig new burrows.
Ray McClain, a professor at the AgCenter Rice Research Station near Crowley, has shown that female crawfish can survive several episodes of being flushed from the ground by flooding and still go on to spawn in the fall if they can get back into a burrow.
Whether that happens will depend on how fast farmers are able to remove standing water and predatory fish.
If rice was planted in the past month for crawfish forage, once fish have been eliminated growers should put a couple of inches of water back to help the rice grow and control some of the weeds.
In fields where rice was harvested, rice straw will be decomposing and water should be drained out as quickly as possible.
The wet ground will help the stubble re-sprout, but producers are encouraged to 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.
In general, these ponds will have serious water quality problems in the fall, so waiting until temperatures have cooled off in mid- or late October to flood is recommended.
“We shouldn’t assume that there is going to be a blanket net negative impact for the industry as a whole,” McClain said in a new release. “I really think there will be negative impacts for some producers, yet others probably will see little or no effect.”
The fact that there shouldn’t be any drought-linked impacts this year is probably going to offset some of the negatives from the flooding.
“Bottom line is – neither the farmers nor the consumers should give up on the upcoming crawfish season just yet,” Lutz says.