CIGR Handbook of Agricultural Engineering, Volume II Animal Production & Aquacultural Engineering, Part II Aquacultural Engineering, Chapter 12 Equipment and Controls

Abstract

First paragraph: Feeding is usually the largest operational cost of growing fish in aquaculture. The feed can represent greater than 50% of the variable costs in growing fish. Labor and feeding equipment must also be considered as contributors to the total cost of feeding the aquacultural crop. Delivering the feed to fish at the right time, in the correct form, and in the right amount is necessary for optimal growth. The choice of feeding equipment depends on factors such as type and life stage of fish, type and size of feed, size of the operation, available labor, and the type of culture system. Therefore, a careful analysis of these factors is essential for successful and profitable fish culture. Feeding regimes in aquaculture can be classified in one of the following three categories [1]: 1. Natural food produced in the growing system: Growing larval stages of many carnivorous fish (for example striped bass) to a size that will accept a formulated diet is most successfully done in ponds in which the fish are presented with natural food. See Geiger and Turner [2] for a more in-depth discussion of pond management techniques for producing live foods. When fish reach the fingerling size (about 2.5 cm), they are trained to feed on a formulated diet for grow-out. If omnivores or herbivores are cultured, the plankton bloom in a pond is manipulated with fertilizer additions similarly to that for carnivores. However, this bloom is continued as the fish grow to provide food for the larger fish. 2. Acombination of natural and formulated food: In some extensive or semiextensive systems, fish are allowed to graze on natural foods available in the water and are also fed formulated feed to supplement their diet. 3. All formulated food: Fish in intensive systems are fed their complete nutritional requirements in a formulated diet that has been found to meet desired growth requirements. Proper nutrition is not only a function of feed compositionthe fish will not grow unless they get and consume the feed [3]. Formany cultured species, dry, pelleted formulated diets have been developed to meet total or supplemental dietary requirements. There are some special cases in which feeds other than natural or formulated dry diets are used, but these are beyond the scope of this review. This section focuses on the delivery of dry diets.