Aquaculture is a fast-growing, essential industry that provides food and income to millions of people. It offers the only prospect of expanding food supply from freshwater or sea because capture fisheries have reached their limits. However, many features of aquaculture as currently practiced are ecologically unsustainable. Aquaculture: the ecological issues is written by an international team of researchers. Their aim has been to give an accessible account of the scale and diversity of aquaculture and the impact that it has on habitats and ecosystems throughout the world. Controversial topics such as habitat loss, the introduction of alien species, genetic pollution by escapees from fish farms and spread of disease from farmed to wild populations are covered. Attention is drawn to the heavy reliance of the industry on fishmeal and fish oil derived from industrial fishing that in turn impacts on the food supply of seabirds and fish such as cod and haddock. Aquaculture generates wastes and uses antibiotics and other drugs to stave off disease. The authors show how effects of these problems have been ameliorated and look to a future where improved technology, better regulation and integrated resource management can combine to make the industry more sustainable. This booklet is aimed at policy makers, environmental managers and professional scientists who seek a compact overview. It will also be an invaluable reference book for undergraduates and Masters' level students. It takes a worldview and so is relevant to acquaculture across the globe.