additionally industrial facilities harbours and shipping routes may occupy large areas following an amendment of the aquaculture act in relocation of sites may be enforced by the central authorities ie the directorate of fisheries when necessary due to environmental or socioeconomic concerns furthermore a licence may be withdrawn in accordance with the aquaculture act if production at a particular site is no longer considered to be environmentally appropriate eg when investigations show that ecosystems have been adversely affected by farming activities withdrawal may also be performed if the disease situation or awareness of disease or fish welfare conditions have changed significantly since the licence was granted