Feed should be applied conservatively so that shrimp have an opportunity to consume as much of the feed as possible. This is an important economic consideration, and it also reduces the input of nutrients to ponds. Feed amounts should be based on feeding charts that take into account shrimp biomass.
Estimate of shrimp biomass should be made by frequent samplings with cast nets to determine growth rate. Feeding trays also can be used to ascertain if shrimp are eating most of the feed applied. Some farmers attempt to offer all feed on feeding trays, but this practice seldom is feasible in large, semi-intensive ponds.
Feed should be spread as uniformly over ponds as possible to prevent feed accumulation in specific locations on the pond bottom. Accumulation of feed on the bottom can result in deterioration of soil quality. If possible, feed should be offered more than once per day in order to increase the proportion of applied feed consumed by the shrimp.
Impaired water quality in ponds, and especially low dissolved oxygen concentration, stress shrimp and they do not eat well. They also will be more susceptible to disease, convert feed to shrimp flesh less efficiently, and suffer greater mortality. Therefore, shrimp farmers should strive to maintain good water quality in ponds by maintaining moderate stocking, feeding and fertilization. The pond should be stocked at rates that do not require high feed inputs.
When shrimp are stressed or diseased, they will not consume feed well. Therefore, during periods when shrimp are not eating well, feed inputs should be reduced to minimize waste. However, cloudy weather is not a good reason to reduce feed input if shrimp are eating well and dissolved oxygen concentrations are within the normal range.
The feed conversion ratio (FCR) is one of the most important variables in shrimp farming. Farmers should keep careful records of the amount of feed applied to each pond so that the FCR can be calculated. The goal should be to reduce the FCR to as low a value as practical.
Source: Claude E. Boyd, Ph.D., Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, Alabama 36849 USA – Methods for improving shrimp farming in Central America