v Preface Which of us is not familiar with this situation during the student time: on a Wednesday night, one wants to go out to grab a beer ("just one Duveltje") with friends. Until the end of the night (and several beers later) one was trapped in several discussions about religion, politics, and one's field of study. I have to admit, that I have been involved in plenty of such discussions, which also stems from the fact that I am a very discussion-friendly and curious person. However, I caught myself often saying the same sentence "well, the idea is great, but it actually does not really work as it should" with respect to two topics: Aquaponics and Communism. This might appear to be a somewhat far-fetched statement, however, for those who have neither read Marx nor followed the development of aquaponics the last 30 years: in a nutshell it can be stated that both of these ideas follow bottom-up (i.e. local and circular) approaches (i.e. for small farmers and individuals).Additionally to the above, I honestly believe that in times of the financial crisis -in which multinational corporations such as [think of big corporations that produce GMO seeds that are immune to their pesticides] increase their quasi-monopoly positions on the global food market -a paradigm shift back to human-centred and sustainable agricultural development is required to ensure both (1) healthy (i.e. pesticide free) diets and (2) food independence. In contrast, organic, fair trade, and GMO-free food have recently gained rapidly increasing popularity. Consumers want transparent and extensive information about the origin and manufacture of the foodstuffs they buy. The development of agriculture and how to use (finite) resources efficiently will be crucial with respect to the global development and the future of the earth in general. Right now, we are at a crossroads in our history that will determine whether either the people or the corporations will be empowered. I intended to provocatively illustrate this new class conflict on the book cover with the objective to polarize and thus energize the readers themselves to make thoughts and reflections.So far, I have dedicated over 4 years of my life to study and improve aquaponic systems in the hope that one day their production efficiency will be able to compete with state-of-theart hydroponic food production systems, while improving circularity. In this thesis, I will try to demonstrate why aquaponics does not face the same pitfalls as communism, while sharing the empowering people-minded and bottom-up qualities that are required in the 21st century.