Tuesday, June 28, 2011

Freshwater Prawn Production in Missouri


Freshwater prawns

Freshwater prawns (Macrobrachium rosenbergii) are a tropical species of shrimp native to Malaysia. They have been produced in the southern United States since the 1970s. New cultural techniques and management practices for use in temperate climates have dramatically increased the potential for producing prawns commercially in the central United States.

Recent research has been conducted at the Lincoln University George Washington Carver Farm and at the MU Bradford Research and Extension Center to demonstrate that freshwater prawns can successfully and profitably be produced in mid-Missouri. A new MU Extension guide sheet, Freshwater Prawn Production in Missouri, provides research-based information on culture and management techniques that have been successful in producing freshwater prawns and making sound decisions before investing in a prawn production enterprise.

The three defined phases for culturing freshwater prawns are hatchery, nursery and pond grow-out. Producers in Missouri contemplating a freshwater shrimp production enterprise should initially forego the hatchery and nursery phase and purchase juveniles from a reliable supplier to stock ponds for grow-out.

Production of freshwater prawns involves stocking juveniles into ponds, followed by a four- to five-month period of grow-out, until they are ready for harvest. The exact grow-out time depends on the range of water temperatures within the growing season, which in most of Missouri is typically from mid- to late-May until mid-October. Stocking juveniles can begin when water temperatures warm up to 68 degrees F.

Successfully producing prawns in ponds during the grow-out phase begins with planning for a water source, pond site selection and pond construction. The production cycle requires prestocking preparation, stocking juveniles, feeding, and managing water quality until harvest.


Prawn pond half drained for harvest

Stocking rates that will provide a marketable prawn after a four- to five-month growing season generally range from 8,000 to 12,000 per acre. Lower stocking densities may yield larger prawns but lower total harvested poundage.

Like other types of animal agriculture, successful prawn production is dependent on realizing a high-value product (prawns) from low-cost inputs (fertilizer and feed). To achieve maximum growth, prawns must be provided a continuous source of nutrition as economically as possible without being overfed.

The length of the grow-out phase is significantly different between southern Missouri and central and northern Missouri, and will vary from 110 to 170 days, depending on the latitude of the pond. Harvest should occur when daily water temperatures range from 62 to 68 degrees F four to five days in a row, or before an anticipated cold front may cause lethal water temperatures (below 55 degrees F). In a pond where good water quality management has been practiced, survival may range from 60 to 90 percent at the end of the grow-out season. Yields will typically range from 600 to 1,200 pounds per acre. Weights of prawns will range from 10 to 13 per pound.

Freshwater prawns being harvested
Calculating the costs of production and potential returns is extremely important before investing in a prawn production system. The economics of raising freshwater prawns in temperate climates are quite variable. Fixed costs include land, pond construction and equipment. Annual variable costs include such items as fertilizer, feed, chemicals, juvenile prawns, energy and labor. Weather also plays an important role, as temperatures influence the length of the growing season and can impact profitability.

Seasonal demand for freshwater prawns does exist; however, it is important that your production goals and harvesting practices be developed to coincide with your specific marketing strategy. Financial loss due to lack of demand from live sales and not having adequate storage (holding) facilities can be a reality. Market demand suggests that large, live and iced with heads on freshwater prawns have a lucrative but small niche. A large percentage of markets in Missouri are seasonal and short-term. Most sales result from roadside stands or directly marketing products to restaurants and small grocery stores.

Be sure to read the entire guide sheet to get all the details of biology, preparation of the pond beds, feeding, production, harvesting and marketing that are not in this blog.

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