This final thesis presents the impact of cage fish farming on the marine environment and organisms in the vicinity of breeding installations, primarily fish populations. It dwells into the issue of cage farming as part of the mariculture and the potential influences on fish populations, good or bad, that may occur during fish farming. Potential problems can occur due to the impact of waste generated as a by-product of cultivation. Furthermore, it is possible for fish to escape from the cages to the outside environment, which can result in the transmission of disease on wild populations, as well as the change of genetic material. Due to the food intake during breeding, wild populations of organisms are present near the cages, especially fish, which leads to the emergence of predators that can have a major impact on the natural balance in a particular ecosystem. Impact on marine environment must not be overlooked, which can additionally, directly or indirectly, affect wild fish populations.