Aquaculture interacts with wildlife through its consumption of resources, the process itself and the release of wastes into the environment. Space is required to establish the farm and feed required to promote growth. Young fish is translocated for stocking. Cage structures and the high densities of fish and feed may act as attractants to scavenging and predatory species while routine farm activities disturb sensitive species. Besides to damage to stocks and equipment, predators and scavengers can spread disease or stress farmed stock. There is evidence indicating that many birds and mammals are killed on farms. Methods for deterrence are discussed. Farmed animals may escape or extend their range (e.g. mollusc) and so cause damage to habitats or compete with, or predate on, indigenous flora and fauna. However, there is little evidence from marine environments, and many of the conclusions about impacts on finfish stocks come from the example of salmon.