In recent years the subject of pollution of natural waters by aquaculture has received considerable attention. With increasingly stringent regulation of wastewater quality from fish farms around the world, those involved in the industry need to be aware of the causes of pollution from fish and shellfish farms and of methods by which this pollution may be prevented. This work aims to bring the principles of wastewater treatment and other pollution control techniques for fish and shellfish farming to a wide audience of farmers, students, scientists, engineers - in fact anyone with an interest in aquaculture or pollution control. The text is written with both the specialist and those new to the subject in mind. It should be of interest to fisheries scientists, fish farmers, and aqualculturists.