Like many new farm enterprises, Steve and Dolores Fratesi's freshwater shrimp operation began slowly.
“We were producing catfish and were ready to try something different. Freshwater prawn production seemed like a natural progression from catfish production,” says Steve Fratesi. “We began raising prawns in 1995, but harvest was problematic in that first year, with yields around 300 pounds per acre.”
The second and third years were better, averaging 450 and 700 pounds per acre, respectively. This past year, average yields were 800 to 900 pounds per acre, and the Fratesi's Lauren Farms in Leland, Miss., has grown along with the Delta's freshwater shrimp industry.
In the Fratesi's first year of prawn production, there were only two growers in the state. Mississippi now leads the nation in freshwater shrimp production, with 200 growers and over 600 acres, according to Mississippi State University data. “The industry is settling down, and the number of commercial prawn producers in the state should start to vary less from year to year,” he says.
Lauren Farms consists of about 11 acres in ponds, with a hatchery — one of only five in the nation — and a nursery. “Prawn production costs are about equal to catfish on a per-acre basis. It also helps that we have a four-month growing season that runs from the end of May to the end of September,” says Fratesi.
“Because of that growing season, we don't have the predatory bird problems associated with catfish production — prawns are harvested before the cormorants come in to the area.”
Each freshwater prawn, when stocked, weighs in at a minuscule .25 grams. At harvest, there are about 13 prawns per pound, each weighing about 35 grams. The females molt and are re-fertilized by males, with each male having 10 to 12 mates.
It's a 90-day hatching and nursing process, he explains, to pull females out their tanks, place them in a hatchery tank, and bring them slowly into a saltwater system. The female releases larva into the saltwater, and infants are collected after 28 to 30 days.
Prawns are introduced into freshwater tanks at the post-larval or mini-adult stage. At 30 to 60-days-old, the juveniles then can be sold to other growers and stocked in ponds.
After 120 days in 1- to 2-acre ponds, the prawns are harvested, says Fratesi, who is president of the United States Freshwater Prawn and Shrimp Growers Association.
“This is a distinctive product, with its own characteristics,” says Delores Fratesi. “Prawns are low in iodine and more like a lobster in taste and texture. And with prawn, we're not competing against anything domestically. The United States consumes $2 billion more in shrimp than is harvested in U.S. coastal waters.”
The Fratesi farm is selling freshwater jumbo shrimp tails for $14 per pound, and the entire prawn is selling for about $6 per pound.
Like other freshwater shrimp producers in the Delta, Lauren Farms handles all aspects of production, packaging and distribution of its prawns. Fratesi says she markets the product to restaurants and grocery stores.
“Growers are developing their own markets,” she says. “And as far as the pricing goes, basically it's going in and seeing the prices of seafood in retail markets and knowing what the market will bear.”
She adds that restaurateurs and consumers appreciate the fact that freshwater shrimp are grown under controlled conditions. “They appreciate the fact that they're grain-fed in clean water.”
There are three phases of culture of the freshwater prawn — hatchery, nursery and pond grow-out.
Extension specialists and researchers recommend that producers considering a freshwater shrimp operation should forego — at least initially — the hatchery phase and possibly the nursery phase by purchasing juveniles from a supplier. As production increases and pond grow-out is successful, growers may want to expand by developing nurseries and hatcheries.
“The hatchery phase is the most labor-intensive aspect of prawn production and may be the most cost-prohibitive facet of production for those new to the industry,” says Steve Fratesi.
Continuing research by Mississippi State University has demonstrated that freshwater prawn production and grow-out of juveniles can be profitable. Unless growers have a hatchery/nursery, they'll have to purchase juveniles for the pond grow-out phase.
A water temperature greater than 68 degrees F for approximately 100 days is necessary for pond grow-out. The grow-out of prawns to market size — 30 to 100 grams — is best accomplished by stocking them into ponds. The average stocking density ranges from 10,000 to 15,000 prawns per acre, and a grower can expect yields of 500 to 900 pounds per acre if everything goes according to plan.
Harvests greater than 1,200 pounds per acre have been accomplished in research ponds but have never been achieved in commercial ponds. Experienced commercial growers are starting to reach that elusive 1,200 yield mark, however. Fratesi says he had one pond in 2003 that yielded 1,100 pounds per acre.
Researchers recommend that ponds be designed to completely drain in less than a day. To accomplish this, there must be a slope of approximately 4 inches per 100 feet of pond length. There must be one or two drain pipes in the deepest part of the pond, depending on the size of the pond.
A drain of approximately 10 inches in diameter is needed for each acre of water. For example, a 3-acre pond may need two 15-inch drains to operate efficiently. “What is most important is that the water is properly regulated as it drains, so that the prawns have time needed to walk out of the pond,” says Fratesi.
However, when the pond reaches approximately 12 inches deep, only one 10-inch drain pipe may be necessary. This prevents water from draining completely before providing an adequate opportunity for the prawns to follow the water through the drain pipe. A catch-basket should be constructed on the outside of the levee to collect any prawns that exit through the drain.
This method of harvesting is efficient if the pond drains at the proper speed, with low volumes of water remaining in the pond. Most prawns can be collected easily in a catch basket on the outside of the levee. The remaining prawns will be concentrated in the catch basin in the pond and can be removed with a net or by hand from the bottom of the pond.
The bottom of the pond should be smooth, without any holes or depressions that would retain water and prawns as the pond drains.
With proper pond design, researchers agree, harvesting can be time- and labor-efficient. The standpipe should be equipped with a swivel valve. The height of the standpipe will determine the depth of the pond. An anti-seep collar should be used on the drain pipe deep in the levee to prevent water from seeping along the edge of the drain pipe.