The (0) TERM aquaculture is defined as 'the art of increasing and rearing aquatic animals and plants'. It covers activities whose main object is the production of fresh-water, (1) ............ and marine species by man under controlled or semi-controlled conditions. The production of living matter from the aquatic medium is fundamental (2) ............ all aquaculture activities; aquaculture is based on the manipulation of the natural or (3) ............ aquatic environment for the production of species which are useful to man. It (4) ............ involves all aspects of production of living matter in water. There is no (5) ............ and fast distinction between the culture of plants and the rearing of animals as on land where plant crops and animals can be considered separately, but there are different (6) ............ imposed by the characteristics of the species being cultured. The ongrowing of fish at high density has all the characteristics of animal rearing while that of mussels or oysters, depending more on natural seasonal rhythms, is more similar to terrestrial plant crops. In the (7) ............ sense, aquaculture includes activities associated (8) ............ the preparation of animals and plants for sale and their marketing.