Periphyton, as described in this book, refers to the entire complex of attached aquatic biota on submerged substrates, included associated non-attached organisms and detritus. Thus the periphyton community comprises bacteria, fungi, protozoa, algae, zooplankton and other invertebrates. Periphyton is important for various reasons: as a major contributor to carbon fixation and nutrient cycling in aquatic ecosystems; as an indicator for changes occurring in the aquatic environment; it is used to improve water quality in lakes and reservoirs; it increases food availability in aquatic systems; it provides food for fish and shellfish; it can be used for waste water treatment. This book provides an international review of periphyton ecology, exploitation and management. The ecology part focuses on periphyton structure and function in natural systems. The exploitation part covers its nutritive qualities and utilization by organisms, particularly in aquaculture. The final part considers the use of periphyton for ecology, exploitation and management. The ecology part focuses on periphyton structure and function in natural systems. The exploitation part covers its nutritivequalities and utilization by organisms, particularly in aquaculture. The final part considers the use of periphyton for increasing aquatic production and its effects on water quality and animal health in culture systems.