Aquaculture is the culture of the natural product of water (fish, crustaceans, algae and other aquatic organisms). The term is distinguished from fishing by the idea of an active human effort to maintain or increase the number of organisms involved, as opposed to simply taking them into the wild. Aquaculture include subsets mariculture (aquaculture in the ocean); Algaculture (the production of kelp / seaweed and other algae); Fish farming (raising fish – cat, tilapia and milkfish in freshwater and brackish ponds or in salmon ponds); and culture of cultured pearls. Extensive aquaculture is based on local photosynthetic production while intensive aquaculture is based on fish fed with an external food supply.
Aquaculture has been used since ancient times and can be found in many cultures. Aquaculture has been used in China c. 2500 BC. When the waters subsided after the floods of the river, some fish, mainly carp, were retained in artificial lakes. Their brood was then fed with nymphs and silkworm excrement, while the fish themselves were consumed as a source of protein. The Hawaiian people practiced aquaculture by building fish ponds (see Hawaiian Aquaculture). A notable example of ancient Hawaii is the construction of a fish pond, at least 1000 years old, in Alekoko. The Japanese cultivated seaweed by providing bamboo poles and later nets and oyster shells as spore anchors. The Romans often raised fish in ponds.
The practice of aquaculture gained prevalence in Europe in the Middle Ages, because fish were rare and therefore expensive. However, improvements in transportation during the 19th century made fish readily available and inexpensive, even in inland areas, causing a decline in practice. The first North American hatchery was built on Dildo Island, Newfoundland and Labrador, in 1889. It was the largest and most advanced in the world.
Americans were rarely involved in aquaculture until the end of the 20th century, but California residents harvested wild kelp and made legal efforts to manage supply by starting c. 1900, later even producing as a war resource. (Peter Neushul, Seaweed for War: California’s First World War Kelp Industry, Technology and Culture 30 (July 1989), 561-583)
Unlike agriculture, the rise of aquaculture is a contemporary phenomenon. According to Professor Carlos M. Duarte About 430 (97%) of the aquatic species currently in cultivation have been domesticated since the beginning of the 20th century, and about 106 aquatic species have been domesticated during the last decade. The domestication of an aquatic species usually involves about ten years of scientific research. The current success of domestication of aquatic species is the result of increased knowledge of the basic biology of aquatic species in the 20th century and lessons learned from past successes and failures. The stagnation of the world’s fisheries and the overexploitation of 20 to 30% of marine fish species have given an additional impetus to the domestication of marine species,
In the 1960s, the price of fish began to rise as wild fish catch rates peaked and the human population continued to increase. Today, commercial aquaculture exists on an unprecedented scale. In the 1980s, open sea salmon farming also developed; this particular type of aquaculture technology remains a minor part of the production of farmed fish around the world, but possible negative impacts on wild stocks, which have been questioned since the late 1990s, have led to a major controversy. 
In 2003, total world production of fishery products was 132.2 million tonnes, of which 41.9 million tonnes or about 31% of total world production. The growth rate of global aquaculture is very fast (over 10% per year for most species) while the contribution to total wild fisheries has been essentially zero in the last decade.
In the United States, about 90% of all shrimp consumed is grown and imported.  In recent years, salmon farming has become a major export in southern Chile, particularly in Puerto Montt and Quellón, Chile’s fastest growing city.
Farmed fish are kept in concentrations never seen in the wild, for example 50,000 fish in an area of 2 acres (8,100 m 2 ),  with each fish occupying less space than the average bath. This can cause several forms of pollution. Packed tightly, the fish rub against each other and the sides of their cages, damaging their fins and tails and becoming ill with various diseases and infections. 
Some sea lice species target farmed coho salmon and farmed Atlantic salmon in particular.  Such pests can have an effect on nearby wild fish. For these reasons, aquaculturists often need strong drugs to keep the fish alive (but many fish still die prematurely at rates up to 30%  ) and these drugs inevitably enter the environment.
The lice and pathogen problems of the 1990s facilitated the development of current treatment methods for sea lice and pathogens. These developments have reduced stress caused by pest and pathogen problems. However, being in an ocean environment, the transfer of pathogens from wild fish to aquaculture fish is an ubiquitous risk factor. 
The large number of fish kept in one place in the long term produces a significant amount of condensed faeces, often contaminated with drugs, which again affect local waterways. However, these effects appear to be local at the actual fish farm site and may be minimal or unmeasurable in high intensity sites. [ citation needed ]
Integrated multitrophic aquaculture
Integrated Multi-Trophic Aquaculture (IMTA) is a practice in which the by-products (wastes) of one species are recycled to become inputs (fertilizer, feed) for another. Fed aquaculture (fish, shrimp) is combined with inorganic extraction (eg algae) and extraction of organic matter (eg shellfish) from aquaculture to create balanced systems for a sustainable environment (biomitigation), the economic stability (product diversification and risk reduction) and social acceptability (better management practices). 
The term “multi-trophic” refers to the incorporation of species from different trophic or nutritional levels into the same system.  This is a possible distinction from the age-old practice of aquatic polyculture, which could simply be the co-cultivation of different fish species of the same trophic level. In this case, these organisms can all share the same biological and chemical processes, with few synergistic benefits, which could potentially lead to significant changes in the ecosystem. In fact, some traditional polyculture systems may incorporate a greater diversity of species occupying several niches, as large (low intensity, poor management) crops in the same pond. The term “integrated” in IMTA refers to the more intensive cultivation of different species in close proximity to one another, linked by the transfer of nutrients and energy through water,
Ideally, the biological and chemical processes in an IMTA system should be balanced. This is achieved through selection and appropriate proportions of different species providing different ecosystem functions. Co-cultivated species should be more than just biofilters; they should also be exploitable crops with commercial value.  An IMTA operational system is expected to result in higher production for the whole system, based on mutual benefits for co-cultivated species and better ecosystem health, even if individual production of some species is lower. to what could be achieved in short-term monoculture practices. 
Sometimes the more general term “integrated aquaculture” is used to describe the integration of monocultures by the transfer of water between organisms.  For all intents and purposes, however, the terms “multinational aquaculture” and “integrated aquaculture” differ mainly in their descriptive character. These terms are sometimes interchanged. Aquaponics, fractional aquaculture, IAAS (Integrated Agriculture-Aquaculture Systems), IPUAS (Integrated Peri-Urban Systems-Aquaculture) and IFAS (Integrated Fisheries-Aquaculture Systems) can also be considered as variants of the IMTA concept.
A shrimp farm is an aquaculture enterprise for growing shrimp or shrimps for human consumption. Commercial shrimp cultivation began in the 1970s and production increased sharply, especially to meet the demands of the United States, Japan and Western Europe. Total world production of farmed shrimp reached more than 1.6 million tonnes in 2003, worth nearly US $ 9 billion. About 75% of farmed shrimp are produced in Asia, particularly in China and Thailand. The other 25% is produced mainly in Latin America, where Brazil is the largest producer. The largest exporting nation is Thailand.
Shrimp farming has moved from China to Southeast Asia into a meat packing industry. Technological advances have led to the growth of shrimp at ever increasing densities, and broodstock are shipped worldwide. Virtually all farmed shrimp are Penaeids (that is, the family Penaeidae) and only two species of shrimp – Penaeus vannamei (Pacific white shrimp) and Penaeus monodon (giant tiger shrimp) – account for about 80% of all farmed shrimp. These industrial monocultures are very sensitive to diseases that have caused several regional erosion of shrimp populations. Growing environmental problems, repeated epidemics, pressures and criticism from NGOs and consumer countries led to changes in the industry in the late 1990s and generally stronger regulation by governments.