3.2 Impacts on the ecosystem, and the natural and cultural landscape

Technical installations, pollution, spreading of new species and spreading of fish diseases may, alone or combined, cause such drastic environmental impacts that the original ecosystems are changed. This can affect other forms of economic exploitation of these areas. The occurrence and the produced amount of other utilizable species can be altered, and the suitability of the water body for other uses can be changed.

Special care should be taken if the farm is situated in, or near, vulnerable or conservation-worthy ecosystems, e.g. mangrove swamps or coral reefs. Mangrove swamps have in some places been under great stress, because they are attractive for shrimp and oyster production. Great harm can be done to their natural function as propagation and growth areas for other valuable species.

Large aquaculture farms in marine coastal areas can be so attractive to sea birds that they may migrate from their natural habitats.

The scope of likely impacts on the ecosystem depends on the scale and intensity of the project. Generally speaking, extensive and semi-intensive aquaculture projects are more adaptable to the ecosystem than are the intensive ones.

Large aquaculture farms may entail considerable encroachments on the landscape.

The visual character of the natural and cultural landscape may alter so that it becomes less attractive for recreation and tourism etc.. Historic remains, buildings and other landscape elements that are important to the local population can also be affected. In order to reduce the impacts on the landscape, one ought to make values of landscape part of the planning process with respect to mitigative and reconstructive measures.