Happy Birthday, Cajun Crustacean! You’re 200 million years old, give or take a few millennium.Louisiana’s commercial species of crawfish, the red swamp crawfish (Procambarus clarkii) and the white river crawfish (Procambarus zonangulus) must be plenty smart little animals to have existed on Terra for such a long time.
Dr. Jay Huner, the retired director of the University of Louisiana at Lafayette’s Crawfish Research Center, agreed.
“Crawfish are from the Jurassic Period or before,” he said. “They’re not foolish.”
In late summer and early fall, crawfish habitat is drying up and Louisiana’s famous decapods are looking to hunker down in the ground. Ground hunkering is also known as burrowing. The swampy wetlands, once covered with water, begins to sprout vegetation. The crawfish don’t mind this at all. They’re used to it (remember, they’re 200 million years old). They can survive dry periods. What they’re really worried about is predators. Digging a hole in the ground thwarts a lot of crawfish predators.
Throughout crawfish season, the lady crawfish have been looking for boyfriends and mating generally occurs in open water. Crawfish, however, are plenty adaptable. Dr. Robert Romaire, the former head of the Louisiana State University aquaculture program, said crawfish can also mate in the burrow. The whole process goes something like this: after singing romantic crawfish songs to each other, the male crawfish gives the female crawfish some crustacean sperm. The females, disciples of planned parenthood, store the sperm in a protective receptacle until they’re good and ready to have a family. And they aren’t ready to have a family until they have a safe place to have babies.
In crawfish world, the best place to have babies is in a nice burrow. The mommas are remarkably easy to please. They don’t need a fancy house. They just need a vertical tunnel 40 to 90 centimeters deep, moist, but not too moist, and above the water line. When they know they can have a nice home, they spawn, which is a fancy aquaculturish way of saying she has become “with child.” Make that “with up to 500 children.” She’ll make eggs that will hatch at the proper temperature (a cool 70.4F) in about three weeks. The hatchlings will cling to the swimmerets under her tail through two moltings and then instinctively remain with her for several weeks. But at the end of several weeks, the momma and children are driving each other crazy, and if they don’t leave the burrow, or if there isn’t enough food in the burrow, the mommas will perhaps eat, uh, er, how to put this delicately? Well, she’ll begin to eat her young. (We never said they were great mothers, just wise mothers). That’s why human mothers can’t wait for school summer vacation to end).
Folk wisdom says the momma crawfish won’t release her young until she hears thunder. Now that may sound like an old wive’s tale but some of those old wives were pretty smart too. Crawfish mommas don’t like to release their young until they’re reasonably sure there’s a lot of water around.
“The crawfish will come out (of their burrows) in the late fall when they get the signal that it’s raining,” Doc Huner said. And despite the fact that some sneaky crawfish farmers flood their crawfish ponds in September for November fishing, the burrowed female crawfish will not release her eggs into the wild until they are signaled by rainfall that it is safe to do so.
As mentioned earlier, crawfish sex can happen at any time but most of it occurs in autumn in in several waves.
So have a Happy 200,000,001st Birthday, Cajun Crustacean! We love you in so many ways…let’s see, there’s boiled, etouffee, stew, bisque….
Source: “Crawfish Culture: A Louisiana Aquaculture Success Story” by W. Ray McClain and Robert P. Romaire.
Louisiana Market Bulletin, January 20, 2004; “The Wetter the Fall, the Better the Crop,” by Sam Irwin.