Definitions

The word “aquaculture” is defined by the Food and Agriculture Organization of the United Nations (FAO) as follows:

“Aquaculture is the farming of aquatic organisms including fish, molluscs, crustaceans and aquatic plants. Farming implies some sort of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated. For statistical purposes, aquatic organisms which are harvested by an individual or corporate body which has owned them throughout their rearing period contribute to aquaculture” (FAO 1997b).
Current aquaculture technology allows the commercial and viable production of a number of organisms through the management of their entire life cycles. The “seed” materials (larvae and juveniles) are produced under controlled conditions, starting from the maturation of broodstock, which eliminates the need for the collection of juveniles from the wild.

Closed life-cycle aquaculture involves a thorough understanding of the behaviour, habitat and environmental requirements, reproductive biology, nutritional requirements, and larval and juvenile physiology of each species, as well as its susceptibility to disease under culture conditions. Moreover, it involves the development of all aspects of fish husbandry, such as the facilities required for the various life-cycles stages (broodstock holding tanks/sea cages, nursery tanks/cages, grow-out facilities), feed development, fish handling systems, and disease control. Such procedures and techniques have been developed for several diadromous and marine fish species – notably salmonids, seabass, seabream, and more recently for cod.
Another definition of aquaculture was derived by Beveridge (1996):
“Aquaculture, or the farming of aquatic organisms, is achieved through the manipulation of an organism's life cycle and control of the environmental variables that influence it. Three main factors are involved: control of reproduction; control of growth; and elimination of natural mortality agents. Control of reproduction is an essential step, otherwise farmers must rely on naturally spawning stocks. The supply of fry from the wild may be restricted to a particular season and a particular area, and there may also be shortages due to over exploitation of wild stocks”.

Many species that are commercially important cannot currently be spawned in captivity. For others, the complete life cycle has only been completed at the research and development level, which means that insufficient “seed” material is available for commercial farming operations. Where controlled breeding techniques have not been perfected, farmers have to depend on “seed” available from the wild. In these types of aquaculture practices there is a need to collect “seed” fish directly from the wild, ranging from larvae, small to medium-sized juveniles, or even large individuals.
These “semi-aquaculture practices” have not previously been defined exactly: the terms that are currently used include farming, caging, penning, and fattening, depending on the size, species, and the timescale of the culture practice, i.e. the activities that are related to the on-growing of the fish. When the rearing of tunas caught from the wild is discussed, their culture is denominated in various ways, depending on whether the on-growing/fattening activity is being referred to by working groups, or by those involved in marine aquaculture (mariculture) or fisheries. These differences in terminology have been observed in documents from FAO, the General Fisheries Commission for the Mediterranean (GFCM), and the International Commission for the Conservation of Atlantic Tunas (ICCAT). In the Mediterranean, current practices could be described as “tuna farming” and “tuna fattening”. The first, carried out mostly in Croatia, is where the overall weight of small fish is increased substantially through culture periods ranging from 1 to 3 years. In the latter case, larger fish are kept in cages for a shorter period to increase their fat content, a factor which allows them to be sold for a better price in commercial markets, especially in Japan.
The fundamental difference between the use of the terms “aquaculture” and “farming” by Beveridge (1996) and FAO (1997b) is that the former applies these terms only to practices where the reproduction of the organism is controlled, while the FAO definition is more general: “…some sort of intervention in the rearing process to enhance production...”. Inability to complete the life-cycle in captivity does not bar the farming activity from being considered as aquaculture under the FAO definition.
A more holistic approach is needed, one that acknowledges the links between aquaculture and fisheries. According to Williams (1996): “for too long fisheries and aquaculture have been treated as sectors in isolation, a practice that has ignored important linkages and externalities”. The release of hatchery-reared animals into the wild for capture fisheries enhancement, being aquaculture-driven, is referred to as “culture-based fisheries” (FAO 1997b). However, there is a need for a better understanding of “semi-aquaculture practices” where the farming activity is based on the stocking of wild-caught animals. For this report, it has been necessary to derive and adopt a new term, in order to avoid confusion and to identify the issues related to such farming practices easily. This term is “capture-based aquaculture”. This term represents an overlap between fisheries and aquaculture and is defined as follows:
Capture-based aquaculture is the practice of collecting “seed” material – from early life stages to adults - from the wild, and its subsequent on-growing in captivity to marketable size, using aquaculture techniques.
Capture-based aquaculture has developed due to the market demand for some high value species whose life cycles cannot currently be closed on a commercial scale.