Production Units: a Classification
The aim of the production unit is to create a restricted area where aquatic organisms can be reared under the best possible growth conditions. A habitat must be created for the aquatic organisms within a body of water. In the unit the organisms (apart from eggs) need to have access to food and oxygen; in addition, the waste products must be removed. Optimal performance of the production units is of major importance because they constitute the production system on the farm.
When starting to develop production units, the aim is to create an environment that resembles natural conditions as much as possible. Over a period of time after the species have gone through breeding programmes and become more adapted to farming conditions, the production units may also be developed to increase cost effectiveness by achieving greater production coupled with reduced investment and operating costs.
The design of the units depends on the organ-isms, for instance whether fish or shellfish are being farmed, and will also vary with the species. For instance, requirements for flatfish are different from those of pelagic fish, the former requiring a larger bottom area. Requirements may also change with the development stage and will be different for eggs and on-growing fish.
During the past few years, animal welfare considerations have been introduced into fish farming. Therefore the production units should be designed to allow the fish to behave as naturally as possible.
In the production unit oxygen and eventually feed are consumed by the organism, and waste products are released. The amount of oxygen consumed depends on the fish density, amount of feed supplied and the growth rate.