• By Mark Shirley •
Survival of the brood stock is critical in order to populate the pond with crawfish in the fall. The following are a few tips that may help.
■ The rice stand needs to be dense enough and have at least 4-6 inches of water before you add crawfish to the field. Crawfish need cover for a few days or weeks before they burrow into the sides of the levees. If the rice is thin, the crawfish are easy prey for birds. Also, the sun and heat can cause high mortality.
■ Select healthy crawfish for stock and be sure that at least 50% are females. Many of the mature females have already buried, leaving a higher percentage of males and immature crawfish left in the field. Check every sack to be sure no White River Crawfish are present!
■ Crack open a few female crawfish to check overall health and egg development. Bright yellow fat indicates a healthy crawfish that is likely to survive until the fall. Greenish brown colored fat is an indication of poor health, which could mean poor survival during the summer.
■ Mature female crawfish will have developing eggs that will be yellow to dark brown in color. Very small ovaries with tiny, white eggs are an indication of an immature female crawfish.
■ If possible, move stock crawfish into the new pond on a cloudy or even a rainy day. The longer the crawfish are out of the water, exposed to heat, sun and wind, the higher the initial mortality. Don’t use crawfish that have been stored in a cooler overnight.
■ Source, size and genetics are not factors when selecting stock. Maturity, health and survival are much more important. Many studies over the past 40 years have shown that population density, water quality and food supply are by far the most important influences on size of the crawfish next season.
A more lengthy discussion of stocking can be found on pages 22-25 of the Crawfish Production Manual. There are also some good pictures on page 6 that show the egg development in female crawfish.
If you have questions about your particular operation, you can reach me by phone at 337-898-4335 or by email at Mshirley@agcenter.lsu.edu.
Mark Shirley is Louisiana State University AgCenter and Louisiana Sea Grant crawfish, aquaculture and coastal resources specialist based in Abbeville, Louisiana. he may be reached at Mshirley@agcenter.lsu.edu.