Crawfish should be stocked into the ponds in the spring by early June. At this point, pond construction should be fully completed such that no more earth moving is necessary. Ponds should be flooded to a depth of at least 12 inches for the stocking. 50 to 100 lbs. of freshly caught crawfish are needed per acre for stocking. When possible, crawfish to be used for stocking should be sampled to determine adequate egg development. 20 randomly selected female crawfish should be sacrificed by removing the tail. Looking into the now open thorax area between the two lobes of hepatopancreas (or "fat"), at least 4 of the female crawfish should have dark brown to black eggs. The black eggs will be about the size of 12 shot (or rat shot). Egg development in crawfish can be determined by absence of eggs and color. The egg stages go from no eggs to eggs that progress in color from white to yellow to tan to brown to black and then the eggs are laid. Ideally, 20% of the females should have the gravid eggs, or the brown or black eggs.
The reason for 50 to 100 lbs. of crawfish for stocking is that this is the number that need to be stocked to in order to have the potential for a yield the following year of 1000 lbs. per acre or more. Marketable size crawfish are generally considered to be 4 inches in length or better. A 4 inch crawfish weighs about 1.1 oz. or is about a 15 count crawfish (15 to the lb.). In order to produce 1000 lb. of crawfish per acre, you need to have 15,000 crawfish present to begin with. In a fairly well managed pond, an average survival is going to be about 50%, so you now need 30,000 crawfish per acre to produce that 1000 lb./ac yield. A female crawfish generally produces about 100 eggs per inch of body length, so a 4 inch female crawfish will produce about 400 eggs. Therefore, you need 75, 4 inch female crawfish to be able to produce 30,000 needed crawfish. 75, 4 inch female crawfish will weigh about 5 lbs. Stocking ratios of male to female should also be about 1:1, so you also need 5 lbs. of male crawfish. Also, as mentioned earlier, only 20% of the females need to be gravid, so you need an additional 40 lbs. of crawfish to get that 20% gravid female crawfish average. So, you need a minimum of 50 lbs. per acre of crawfish to stock in order to have a chance of producing 1000 lbs. per acre yields. Many crawfish producers in North Carolina hedge the bet by adding 25-50 lbs. per acre to the minimum stocking rate to ensure good production.
When stocking the crawfish into the pond, the crawfish should be distributed as evenly as possible throughout the pond. This is usually accomplished by walking through the pond carrying a 30-40 lb. sack of live crawfish and "sprinkling" them out a few at a time into the water.
After the pond is stocked, the pond water level can be dropped slowly, no more than 1 inch per day, to encourage the crawfish to burrow. The crawfish will begin to burrow into the pond levee at the high water mark. As the water level drops, newly exposed pond bottom will become the high water mark and the remaining crawfish will burrow into it until the pond is completely drained and all of the crawfish have burrowed. Cover from the sun will encourage crawfish to burrow. Some producers will add this cover in the form of hay or straw or pieces of cardboard. A consideration for good survival during stocking is to remember that the maximum lethal temperature for crawfish is about 95oF.
When the crawfish burrow into the high ground, such as a levee, they will generally burrow laterally for a short distance to get out of the direct sunlight and then proceed to burrow down to the where the ground moisture is located. The crawfish will then remain at this level and breath the air within the burrow as long as there is adequate moisture or humidity to keep the gill moist.