Dear Crawfish Farmers:
A new season is approaching and everyone is hoping for a better production year. The combined effects of drought and hurricanes impacted almost all producers in all parts of the state last year. At least we have had a little more rain this summer which should help the survival of the burrowed brood stock. That should, could, might mean more crawfish than last year. In a few months we’ll find out.
Flooding
Based on years of research findings and observations throughout the state, researchers at the LSU AgCenter still recommend flooding in early October. Flushing ponds or holding shallow floods (4-6 inches) during September helps rice grow and starts the straw and weeds to decompose. This shallow water is fine and sets the stage for a better food supply later in the season. Farmers should wait until sometime in October to bring the water level to 12 inches or more. Briefly flooding to a deeper level can encourage the emergence of crawfish buried higher on the slope of the levee. Otherwise keep the flood about 12 inches deep for the first 4-6 weeks. Monitor the water quality and flush as needed.
October is the time when more of the brood stock are actually spawning and hatching young. Only a very small percentage of the brood stock actually spawn in September. Early flooding does not speed up the spawning process. You may see a few female crawfish with babies crawling around after a big rain in September but many more will emerge with young in October and November.
Fields planted with rice just for crawfish should flood only as deep as the young rice can take at this time. As the rice grows taller, the depth can be increased. Where sorghum-sudangrass was planted, keep these fields dry until the forage reaches about 3 to 4 feet tall. Once flooded the sudangrass will stop growing and begin to slowly deteriorate. Ponds with natural vegetation (weeds) should delay flooding until mid or late October since most weeds die and decompose rapidly in the first few weeks covered with water.
Soil Amendments
Over the years, there have been several research projects that looked at soil and water chemistry factors as they relate to crawfish production, particularly with respect to calcium, phosphorus and other minerals. None of the studies indicated the need for any fertilizer or soil supplements to enhance crawfish production. The amount of calcium or other minerals taken out of the field by harvesting crawfish is extremely small compared to the amount of calcium in the soil already and the amount of calcium added to the pond each year through flooding. Soils would have to have a pH less than 5 and very soft water (hardness less than 50 ppm) to possibly have a measurable affect on crawfish production.
If you are concerned about the soil or water chemistry, have an analysis run to determine if something is needed. Researchers suggest having an analysis done to see if the vegetation in the pond (rice, sorghum-sudangrass or weeds) may need something. Routine soil tests are only $7.00 per sample, irrigation water analysis is also $7.00 per sample. Contact your parish Extension office for details on sampling procedures.
Besides the cost involved, adding fertilizer or other things to the soil or water can have negative affects on the pond ecosystem. Too much nitrogen can stimulate the growth of filamentous algae that can cover traps and lead to oxygen problems. Too much calcium may raise the soil pH to the point that rice growth is affected.
LCFA Events
The Louisiana Crawfish Farmers and Ranchers Association have two upcoming events planned. On Tuesday, October 10, there will be an Annual Meeting, Banquet and Social beginning at 6:00 p.m. at the Rayne Civic Center. Then on Tuesday, November 7, the association will host their Crawfish Expo at the Rayne Civic Center. This year the Expo will be held indoors with a large number of exhibitors and vendors displaying their products. For more information about tickets to these events or joining the LCFA, call the association office at (337)394-8182 or visit their website at: www.crawfishfarmer.com.
If you have any questions about production practices or particular problems in your ponds, contact me at (337) 898-4335 or by email at: mshirley@agctr.lsu.edu
Sincerely,
Mark Shirley
SW Region Aquaculture Specialist
LSU AgCenter