Aquaculture
In 2019, global aquaculture operations produced over 120 million tonnes of aquatic organisms. This output was valued at US$274 billion. By 2022, production had risen to 130.9 million tonnes and reached a value of USD 312.8 billion. The Food and Agriculture Organization defines this practice as the farming of aquatic organisms including fish, molluscs, crustaceans, and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production. Regular stocking, feeding, and protection from predators are common interventions. Individual or corporate ownership of the stock being cultivated is also required for it to be considered aquaculture. This controlled cultivation contrasts sharply with commercial fishing which harvests wild fish without such management. Aquaculture involves cultivating freshwater, brackish water, and saltwater populations under controlled or semi-natural conditions. It serves as an environmental source of food and commercial products that help improve healthier habitats. The industry is used to reconstruct the population of endangered aquatic species. Technology has increased the growth of fish in coastal marine waters and open oceans due to the increased demand for seafood.
The Gunditjmara people in south-western Victoria, Australia, may have raised short-finned eels as early as about 4,580 BCE. They developed about 10 hectares of volcanic floodplains in the vicinity of Lake Condah into a complex of channels and dams. Woven traps were used to capture eels and preserve them to eat all year round. Oral tradition in China tells of the culture of the common carp as long ago as 2000, 2100 BCE. The earliest significant evidence lies in literature, specifically The Classic of Fish Culture by Fan Li written around 475 BCE. Another ancient Chinese guide to aquaculture written by Yang Yu Jing around 460 BCE shows that carp farming was becoming more sophisticated. Ancient Egyptians might have farmed fish from Lake Bardawil about 1,500 BCE and traded them with Canaan. Romans bred fish in ponds and farmed oysters in coastal lagoons before 100 CE. In medieval Europe, early Christian monasteries adopted Roman aquacultural practices. The 15th-century fishponds of the Trebon Basin in the present-day Czech Republic are maintained as a tentative UNESCO World Heritage Site. In the first half of the 18th century, German Stephan Ludwig Jacobi experimented with external fertilization of brown trout and salmon. By 1864, Seth Green had established a commercial fish-hatching operation at Caledonia Springs near Rochester, New York. When the Dildo Island fish hatchery opened in Newfoundland in 1889, it was the largest and most advanced in the world.
Worldwide, the most important fish species used in fish farming are carp, salmon, tilapia, and catfish. Commercial shrimp farming began in the 1970s and production grew steeply thereafter. Global production reached more than 1.6 million tonnes in 2003 worth about US$9 billion. About 75% of farmed shrimp is produced in Asia particularly in China and Thailand. Aquacultured shellfish include various oyster mussel and clam species. These bivalves are filter and/or deposit feeders which rely on ambient primary production rather than inputs of fish or other feed. Abalone farming began in the late 1950s and early 1960s in Japan and China. Since the mid-1990s this industry has become increasingly successful. In May 2017 a Belgian consortium installed the first of two trial mussel farms on a wind farm in the North Sea. Microalgae constitute the majority of cultivated algae while macroalgae commonly known as seaweed have many commercial uses but are not easily cultivated on a large scale. Mariculture is the cultivation of marine organisms in seawater variously in sheltered coastal waters open ocean and on land. Farmed species include algae shellfish lobster oysters clams and marine finfish.
About 20 percent of mangrove forests have been destroyed since 1980 partly due to shrimp farming. An extended cost, benefit analysis found that external costs were much higher than external benefits over four decades. Of Indonesian mangroves have been converted to shrimp farms. Most of these farms are abandoned within a decade because of toxin build-up and nutrient loss. A farm with 200,000 salmon discharges more fecal waste than a city of 60,000 people. This waste is discharged directly into the surrounding aquatic environment untreated often containing antibiotics and pesticides. There is also an accumulation of heavy metals on the benthos near the salmon farms particularly copper and zinc. In 2016 mass fish kill events impacted salmon farmers along Chile's coast and the wider ecology. Increases in aquaculture production and its associated effluent were considered possible contributing factors to fish and molluscan mortality. Whole-lake experiments at the Experimental Lakes Area in Ontario Canada displayed potential for cage aquaculture to source numerous changes in freshwater ecosystems. Significant increases in ammonium and total phosphorus were measured in the hypolimnion of the lake. Annual phosphorus inputs from aquaculture waste exceeded that of natural inputs from atmospheric deposition and inflows.
A single oyster can filter 15 gallons of water a day removing microscopic algal cells. By removing these cells shellfish remove nitrogen and other nutrients from the system. Raising and harvesting kelp and other macroalgae directly remove nutrients such as nitrogen and phosphorus. Regenerative ocean farming grows a mix of seaweeds and shellfish while sequestering carbon decreasing nitrogen in the water and increasing oxygen. One study estimated that 10 square meters of oyster reef could enhance an ecosystem's biomass by 2.57 kg. Shellfish beds or cages provide habitat structure used as shelter by invertebrates small fish or crustaceans. Increased shelter raises stocks of prey fish and small crustaceans by increasing recruitment opportunities. Seaweed farming is a carbon negative crop with high potential for climate change mitigation. The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate recommends further research attention as a mitigation tactic. Filter-feeders filter pollutants as well as nutrients from the water improving water quality. Seaweeds extract nutrients such as inorganic nitrogen and phosphorus directly from the water.
Under guidelines advised by the Farm Animal Welfare Council good animal welfare means both fitness and a sense of well-being in the animal's physical and mental state. This can be defined by the Five Freedoms including freedom from hunger thirst discomfort pain disease injury fear and distress. Recent studies conclude that fish do have the necessary receptors to sense noxious stimuli and so are likely to experience states of pain fear and stress. Sea lice are the primary parasitic problem for finfish in aquaculture causing widespread skin erosion and haemorrhaging. High stocking densities may constrain normal swimming behaviour and increase aggressive competitive behaviours such as cannibalism. Crowding can result in water flow being insufficient creating inadequate oxygen supply and waste product removal. Ammonia is highly toxic to fish at accumulated levels particularly when oxygen concentrations are low. Many interactions cause stress which can facilitate fish disease. Vaccination methods such as injection induce stress because of extra handling. Biological control uses cleaner wrasse to remove lice from farmed salmon. During transport water needs to be maintained to high quality with regulated temperature sufficient oxygen and minimal waste products.
Recirculating aquaculture systems recycle water by circulating it through filters to remove fish waste and food then recirculating it back into tanks. Scientists associated with the Agricultural Research Service found a way to rear saltwater fish using RAS in low-salinity waters. They produced healthy pompano in tanks with a salinity of only 5 parts per thousand while typical ocean salinity is 35 parts per thousand. Some 16 countries now use geothermal energy for aquaculture including China Israel and the United States. In California 15 fish farms produce tilapia bass and catfish with warm water from underground. Collectively these California farms produce 4.5 million kilograms of fish annually. The UN Sustainable Development Goal 14 includes aquaculture aiming to increase economic benefits to small island developing states by 2030. DNA vaccines have become the most cost-efficient method of preventing infectious diseases. mRNA vaccines are alternative to DNA vaccines because they are more safe stable easily producible at large scale and offer mass immunization potential. Uncrewed vessels like ROVs and AUVs are now being used in aquaculture for site planning cage inspection environmental monitoring disaster assessment and risk reduction.
Common questions
What is the definition of aquaculture according to the Food and Agriculture Organization?
The Food and Agriculture Organization defines aquaculture as the farming of aquatic organisms including fish, molluscs, crustaceans, and aquatic plants. This practice requires some form of intervention in the rearing process such as regular stocking, feeding, and protection from predators.
When did the Gunditjmara people begin raising short-finned eels in Australia?
The Gunditjmara people in south-western Victoria may have raised short-finned eels as early as about 4580 BCE. They developed about 10 hectares of volcanic floodplains near Lake Condah into a complex of channels and dams to capture and preserve eels for year-round consumption.
How much global aquaculture production was recorded in 2022?
By 2022 global aquaculture operations had risen to produce 130.9 million tonnes of aquatic organisms. The value of this output reached USD 312.8 billion during that same year.
What environmental impacts are associated with salmon farming waste?
A farm with 200000 salmon discharges more fecal waste than a city of 60000 people directly into the surrounding aquatic environment untreated. This waste often contains antibiotics and pesticides leading to an accumulation of heavy metals like copper and zinc on the benthos near the farms.
Which countries use geothermal energy for aquaculture systems?
Some 16 countries now use geothermal energy for aquaculture including China Israel and the United States. In California alone 15 fish farms produce tilapia bass and catfish using warm water from underground to generate 4.5 million kilograms of fish annually.