Control system for rotifer production

Abstract

Rotifers are used extensively as start feed for many cultured marine fish species and commercial size hatcheries require stable daily supply of high quality rotifers of substantial volumes. This is often done relying on some employees whose knowledge and experience of the process and procedures ensures a stable production. Control techniques have been used in many other industries during many years improving the quality, reliability, predictability and reducing the costs of the production. However, control engineering is not as widely used as in other industries yet and this is the objective of this thesis, study the possibilities of using such techniques in the area of rotifer production at large scale. The benefits of their application will be an increment in the quality and predictability of the production as it becomes less dependant on the experience of people, but on their experience combined with monitoring and control techniques that will maintain the best conditions possible for the cultivation all the time. And also a better use of the resources will be achieved, that leading probably to a reduction of the costs of the production. This thesis makes a study of the biology and cultivation conditions of the rotifers, which is necessary previous to the application of control techniques, and then studies and proposes to different strategies for controlling the growth of the population, one based on the control of the feed density in the cultivation tank and the other based on the egg ratio control. In this work it is mainly done running simulations over a model, but an experiment is also performed for testing the second of the control strategies proposed.