Shrimp Polyculture in Existing Farms
For family farms to survive and grow, alternative income opportunities must be found. Although universities are working on sustainable agriculture opportunities, ideas that work well in a research system are often impractical when applied to the family farm. Freshwater shrimp polyculture research has been confined to university-level trials with astounding production success, but little information has been gathered as to the economics, practicality or commercial product utilization of freshwater shrimp as a farm product. This project applied university-level research to demonstrate an on-farm shrimp culture.
Shrimp is the world’s most valuable aquaculture industry. The United States alone imports an estimated $1 billion in farm-raised shrimp annually. Strong economic growth in many Asian countries is fueling additional demand, while production increases are limited by disease problems in a number of countries. These factors have resulted in increased shrimp prices over the last two years. United States shrimp imports are expected to remain in the 500-million-pound range for the next several years. Continued international price increases could cause restaurant and food service companies to look for substitute products and increase the demand for domestic catch (Aquaculture Outlook, 1995).
1.) Establish a freshwater shrimp production system in an existing farm pond.
2.) Collect water quality, production and cost data on shrimp production systems.
3.) Host a field tour to demonstrate the integration of shrimp production into sustainable agriculture systems.
On a 93-acre swine and beef farm, two existing livestock ponds were used to demonstrate that raising shrimp can provide extra income and not affect the ponds’ ability to provide stock water. In 1994 the ponds were cleaned, fitted with a three-to-one slope on the sides to minimize growth of cattails and other hydrolytic vegetation and fitted with drain pipes that allowed complete drainage. The 0.2-acre pond, which was to be managed intensively with daily feeding and aeration when necessary, was wired for electricity allowing connection for an aerator. The one-acre pond was managed extensively. Both ponds were allowed to fill naturally with winter rain and run-off.
In early June the ponds were stocked with embryonic shrimp shipped from Texas. The 0.2 acre pond was stocked with 3,200 shrimp scheduled for daily feeding. The one-acre pond was stocked with 7,000 shrimp. Regular water sampling for dissolved oxygen indicated early that an aerator was going to be needed in the intensively managed pond. Even with a ram pump bringing in fresh water from a third pond, the heat and drought in late June depleted oxygen levels so that a larger aerator had to be purchased. Problems with excessive aquatic vegetation required weekly hand cleanings.
Feeding levels in the small pond began at three pounds per day and rose to 12 pounds per day for the last three weeks. There was no way to know at the time how much of the pelleted feed was eaten and how much went into organic biomass that fed the plankton and thus fed the shrimp. Total feed consumption was 750 pounds. Also some phosphorus fertilizer was added to increase biomass in the pond. Oxygen levels were sampled by chemical titration methods weekly throughout the season and every three hours the last week when the cold weather necessitated turning off the aerator at night.
Harvest took place September 26. Early unseasonably cold weather reduced the yield. Also because of the cold weather, when the ponds were drained for seining, the shrimp burrowed into the mud rather than jumping into the seine as they would have in warmer weather. Harvest could only be completed by hand harvesting the shrimp out of the mud and then dumping them into a stock tank for cleaning. Despite the problems, nearly 200 pounds of shrimp were harvested.
The shrimp, which started the project weighing one gram each, averaged at harvest 42 grams each. That’s approximately 10-12 per pound live weight. Since tail weight is one half of live weight, the tails were approximately 20 per pound.
Through previous sales of sweet corn and tomatoes, lamb and pork the farm already had in place a customer base for quality foods. Taking advantage of this, the producers announced they would sell the shrimp right out of the pond—live weight at $6.00 per pound. The price was based on processor prices and prices at grocery stores. Although a few were held for sale to a Kroger store, the participants are of the opinion that direct sales from the pond or from a tank at a farmers market will be the most effective marketing strategy.
A survey was mailed to those who bought or received shrimp from the pond. All the responses were positive and enthusiastic about the flavor, texture and size. At $6.00 a per pound, 27 responders said they would purchase a combined total of 540 pounds per year.
The producer plans to expand the shrimp operation by digging three more ponds and adding paddlefish as an additional crop. All the ponds will be aerated and intensively managed so that aquatic vegetation levels can be minimized and oxygen supplies can be maintained. They will also be investigating the best method of developing algae bloom which limits sunlight entrance into the pond, a major factor in vegetation control. Although water and soil sample analysis is not yet complete, it appears shrimp have little impact on water quality. The producers observed that because the shrimp consumed bottom dwellers and algae, the pond water was actually cleaner looking than in previous years.
A field day is scheduled for June 1996. A large crowd is expected since the shrimp project has sparked a lot of local interest.