From its very diversified origin in the different focal areas where aquaculture has developed through long years of tradition, very varied systems of organization have evolved.
Existing aquaculture industries can be classified into: a) small-scale; b) medium-scale; and c) corporate or large-scale operations. In general, worldwide, most aquaculture operations are of small-scale nature. This is particularly true in most developing countries where aquaculture is characterized by the use of small-land areas, perhaps varying from a fraction of hectare to at most 10 ha. The owner-operator or caretaker for this operation, handles the management alone or with the help of his family members, or at most, one or two casually-hired helpers. The management is crude and traditional resulting in relatively low production equivalent or equal to the natural fertility of the water and land of about 300 kg/ha/year or at most a fraction more or twice that of natural productivity but not much more. The operator is generally unschooled or attained limited schooling, and though with a large family, does not have ambition to progress economically. His standard of life is simple and his means of sending his children to school and improving his lot is limited.
The medium-scale aquaculture operation uses slightly bigger areas, say 10 to 50 ha. The. operator may have higher schooling than the former class and is more aggressive in initiating new innovations and modernizing his operations. Normally, his average production is higher, perhaps about 3 or 4 times natural productivity or about 1 ton/ha/year.
Large-scale or corporate aquaculture operators manage hectarage of 50 or more or even by the hundreds of hectares. Here, the operator usually adopts higher scale technology, skilled manpower and attains higher production or produces a specialized high value crop which brings in bigger profits. Production of from 5 to 20 tons/ha/year is not uncommon under this management. The economics of this set-up, however, should be assessed with cost of operation.
In aquaculture, both horizontal as well as vertical integration of management or operation may be possible. Horizontal integration can be characterized by consolidation of all types of aquaculture belonging to one kind of operation, say, milkfish culture, or cage culture, etc.
Vertical integration means the bringing together under one management the operation of one type of the aquaculture industry starting from the selection and acquisition of site, the production of seeds, the rearing in the grow-out, the preparation of feeds, post-harvest processing and marketing of the crop. This is a system that has been starting to develop in corporate aquaculture operations specially for high-investment, high value and export product. This is also the major type of organization suited and adapted in aquaculture in many developed countries.
The environment or sites for the establishment of aquaculture did not have the benefit of a clear legal basis at the start of their establishment. It is only when the industry expanded and became of economic consequence in the different countries that laws or statutes to recognize the legal status of aquaculture establishments were looked into. To start with, the sites for aquaculture were labelled as public domains for the common use of the population in the surrounding communities. When an individual in that community, however, develops an aquaculture industry in a specified site within this public domain, the government authority involved should provide a privilege right for the developer for such a site through laws, orders or special regulations. If this is not provided, there will be conflict or chaos. So far, three systems of granting sites for aquaculture purposes are presently adopted, each with their advantages as well as disadvantages. These are: a) government lease - short-term or annually, or long-term, say 10 to 25 years, and renewable; b) granting of title - this may be granted after the satisfaction of certain conditions and after a certain period; and c) government concession - this is granted for a specific privilege over a definite area for a given duration. Milkfish fry collecting concessions in designated coastal waters in the Philippines is a good example.
Certain aquaculture industries, in the course of their development have evolved a specialization of functions contributing to its rapid progress. For example, the shrimp hatchery production in Taiwan, China has a specialized industry for: a) obtaining adequate and good quality brood-stock; b) hatchery production for nauplii; c) rearing of nauplii up to post-larvae (PL), PL10 and PL20; and d) nursery-rearing of PLs to juvenile.
To attain maximum production from aquaculture establishments, increased investments to implement intensification is resorted to. The levels of intensification can be classified into: a) traditional; b) extensive; c) semi-intensive; and d) intensive. The organization in the traditional system is simple and can be managed by one entrepreneur. In the semi-intensive and intensive systems, the organization is more complex, more diversified and utilizes a large amount of inputs in performing different functions. Investment is also high, including expenditures for engineering and infrastructure improvements and purchase of varied equipments. Using penaeid shrimp culture as an example, a comparison of the different levels of intensification is shown in the following table.
Elements of different intensity levels of management of penaeid shrimp culture in Southeast Asia
| Type | Development/equipment cost (  /ha) | Annual Operating cost ( /ha/crop) | Stocking rate (PL/ha/crop) (No. of crops/yr) | Production (kg/ha/yr) |
| Traditional | 20 000–50 000 | 5 000–10 000 | Variable, mixed species (variable) | 100–400 |
| Extensive | 50 000–100 000 | 10 000–50 000 | 10 000–50 000 (2) | 500–2 000 |
| Semi-intensive | 200–000–500 000 | 100 000–200 000 | 50 000–100 000 (2.5) | 2 500–6 000 |
| Intensive | 500 000–1 000 000 | 200 000–500 000 | 100 000–300 000 or over (2.5) | 7 000–20 000 |
Note: This table is taken from H.R. Rabanal. Development of the aquaculture industry in Southeast Asia: An overview. Contributed to the Seminar on Aquaculture Development in Southeast Asia sponsored by the South-east Asian Fisheries Development Center, Aquaculture Department (SEAFDEC/AQD), Iloilo City, Philippines, 8–13 September 1987 (Table 11).
