February 15-18, 2009 Washington State Convention Center Seattle ...

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EFFECT OF FEEDING RATE ON SURVIVAL AND GROWTH OF L. vannamei REARED IN
LOW SALINITY WATERS OF WEST ALABAMA
Luke A. Roy*, D. Allen Davis and Greg N. Whitis
Department of Fisheries & Allied Aquacultures
Auburn University
Auburn, Alabama 36849 USA
royluke@auburn.edu
Feeding costs have sky-rocketed worldwide in the last year, negatively impacting shrimp farmers. In most areas of the world,
50-60% of production costs in shrimp farm operations are directly attributed to the feed. The increasing cost of feed and fuel
combined with declining market prices for shrimp is making it more difficult to maintain adequate profit margins in the shrimp
industry. In west Alabama, shrimp farmers are located long distances from feed mills and are also forced to pay high shipping
fees for their feed. Due to these reasons, shrimp farmers are always interested in saving money on feed. The low salinity waters
utilized for shrimp culture in west Alabama are quite productive, providing additional natural food items to shrimp throughout
the production season. In order to determine the possibility of reducing feeding rates, an experiment was devised at Greene
Prairie Aquafarm in west Alabama. The experimental system consists of a series of 600 L tanks fed with water from a low salinity
shrimp production pond. Each tank is equipped with two air stones supplied with air from a regenerative blower. Dissolved
oxygen, temperature, and pH were measured twice daily throughout the experimental period, while salinity, ammonia-nitrogen,
and nitrite nitrogen were measured weekly. Thirty tanks were stocked with 20 shrimp (0.80 g initial weight) per tank. A production
diet (Rangen Inc. 40% protein 5% squid) was utilized as the diet for the experiment. Shrimp were offered the diet at
a rate of 60%, 70%, 80%, 90%, 100%, and 110% of a pre-determined daily ration resulting in 6 treatments with 5 replicates.
The 100% treatment represents a typical amount of feed based on an assumed 1.5 g of growth per week and an FCR of 1.25.
The experiment is presently ongoing and will be harvested after 10 weeks. At harvest, growth, survival, percent weight gain,
and FCR will be determined. Results from this experiment will help determine whether west Alabama farmers can reduce feed
rates and rely on the primary productivity of the pond to supply a portion of their nutritional needs.