Urban aquaculture is aquaculture of fish, shellfish, and marine plants in rivers, ponds, lakes, canals located within an urban environment. [1] [2] Urban aquaculture systems can be associated with a multitude of different production locations, species used, environment, and production intensity. The use of urban aquaculture has increased over the last several years as societies continue to urbanise and demand for food in urban environments increases. [3] Methods of production include recirculating systems; land-based culture systems; multifunctional wetlands; ponds, borrow pits and lakes; cages and culture-based fisheries. [3] [4] Most production in urban environments will include either extensive (productivity is based solely on natural runoff) or intensive (tanks and cages of monoculture production), compared to aquaculture in general which is normally semi-intensive.[ clarify ] [3]
Aquaculture dates to 1000 BCE in China. [5] Early examples of European urban aquaculture could be found in Roman villas, followed by monasteries, castles, manors and millponds” in Medieval Europe. [6] The practice variously represented advancements in technology, ways to demonstrate social status, a means to avoid poor fish capture, and an increasing consumer demand for seafood. [6] Significant historical upheavals, such as the fall of the Roman Empire and both the depopulation and economic regression that occurred during the medieval time period disrupted and undermined the practice. [6]
A reemergence of aquaculture became noticeable during the industrialisation era. [5] Urban aquaculture long existed at some level in many areas, but is considered by some to have emerged from the end of World War II through the 1970s, brought on by consumer demand for more seafood and shifting from small-scale community activity to commercial enterprise during this span. The practice has gone global, and continued to steadily increase around the world [4] in the last decade mostly due to increasing demand for shrimps and prawns by developed countries. Aquaculture also provides an alternative livelihood for fishermen faced with reduction of natural marine populations from overfishing and climate change. [5]
Aquaculture is most dominant in Asia, which represents 33% of the world's total fish production; over 70% of Asian production occurs in China. [4] While aquaculture is commonly practices on an industrial basis, the three most farmed fish[ which? ] are from small scale aquaculture. [4]
Urban aquaculture employs water-based systems, the most common, which mostly use cages and pens; land-based systems, which make use of ponds, tanks and raceways; recirculating systems are usually high control enclosed systems,[ clarification needed ] whereas irrigation is used for livestock fish.[ how? ] [7]
Production methods currently used in Europe include recirculation units, horizontally integrated marine aquaculture facilities[ clarify ], and systems exploiting industrial byproducts.[ clarify ] [6]
Urban aquaculture is practiced on land-based culture systems; multifunctional wetlands; ponds, borrow pits and lakes; cages and culture-based fisheries. [3]
Recirculating aquaculture systems (RAS) employ water reuse systems used in many areas. [8]
Acidity | pH 6–9 |
Arsenic | <440 μg/L |
Alkalinity | >20 mg/L (as CaCO3) |
Aluminum | <0.075 mg/L |
Ammonia (non-ionized) | <O.O2mg/L |
Cadmium | <0.0005 mg/L in soft water; <0.005 mg/L in hard water |
Calcium | >5 mg/L |
Carbon dioxide | <5–10 mg/L |
Chloride | >4.0 mg/L |
Chlorine | <0.003 mg/L |
Copper | <0.0006 mg/L in soft water; <0.03 mg/L in hard water |
Gas supersaturation | <100% total gas pressure (103% for salmonid eggs/fry) (102% for lake trout) |
Hydrogen sulfide | <0.003 mg/L |
Iron | <0.1 mg/L |
Lead | <0.02 mg/L |
Mercury | <0.0002 mg/L |
Nitrate | <1.0 mg/L |
Nitrite | <0.1 mg/L |
Oxygen | 6 mg/L for coldwater fish 4 mg/L for warmwater fish |
Selenium | <0.01 mg/L |
Total dissolved solids | <200 mg/L |
Total suspended solids | <80 NTU over ambient levels |
Zinc | <0.005 mg/L |
The potential opportunities include: underprivileged community members may be able to access more affordable food; local production of fish and aquatic plants may prevent food insecurity; livelihoods may improve; and there may be opportunities for high returns on investment. The vast amount of research that Bunting and Little have conducted on this subject gives great legitimacy to their overview of the costs and benefits of urban aquaculture. [2]
The urban aquaculture is of great and undeniable importance, and has multiple benefits, such as securing food and maintaining the offered goods to meet the market's demand, as well as guaranteeing numerous job opportunities and stable income for many families (Bunting et al.). The most important thing urban aquaculture provides to the society and the environment is the fact that it reuses wastewater and by-products from agriculture (Bunting et al.). This offers a valid solution to the problem of limited access to resources and this is why the urban aquaculture should be more widespread and encouraged for all the benefits it brings to the society as a whole. [10]
Another advantage is definitely for the economy. Aquaculture is a great alternative food source and fuel source. It can increase the number of possible jobs since it provides new products and more labor (Bunting and Little, 455). When talking about environmental benefits, aquaculture helps reduce pollution with the help of mollusks and seaweed. It gives a way for sustainable use of sea resources and helps conserve biodiversity. Finally, it reduces the overall environmental disturbance because there is a decreased need for the fishing of wild stock and it provides alternative farming options. [2]
According to Bunting and Little the constraints of urban aquaculture include, production variations, denying access to underprivileged members of a community; urban sprawl; user competition; theft; resource contamination; environmental pollution; high capital costs; financial risks; susceptibility to disease; technical failures; and volatile market conditions. [2] According to one of the authors assessment on urban aquaculture, the world's population residing in cities exceeded half of the total in 2007 and a lot of them getting by in poor economic status. [3]
Bunting and Little (2003) recommends a system-based approach for aquaculture. In the annotated bibliography provided, it was also notable that soil fertility is quickly declining. In addition, by 2030 about ¾ of Latin American will be in cities. [2] This makes it all the more important for urban means of food production. Twenty percent of the food produced by the world is from urban. [2]
Those against aquaculture claim that this method does not help in reducing waste, but rather cause it. In this way, aquaculture becomes a threat to the coastal ecosystem. Many say that it actually contaminates water and threatens the health of those who use that water. Also, some fish food can be contaminated by pesticides and chemicals used to feed the fish. It is said that aquaculture generally has a negative impact on the environment since it has to destroy in order to build fish cages and tanks. [2]
Schreibman and Zarnoch discuss the potential results of implementing urban aquaculture. To do so they use New York City, United States as a model site. They provide great detail on the process of moving “urban aquaculture from concept to practice…” in this specific location. [8] Schreibman and Zarnoch (2009) states that the United States’ strict standard for food production is an open door for good food production from aquaculture. [8] They discuss the potential impacts such systems might have on the environment and economy in metropolitan areas. According to the authors, the success of aquaculture is dependent on the financial support it receives. [8]
Aquaculture was implemented in Cape Town to produce more than two tons of fish annually. Some entrepreneurs like Alan Flemming, whose aim is to provide food to low income communities through an innovative urban aquaculture system, which already received global recognition. With the technology applied, the aquaculture farm supplied Cape Town's 39 top restaurants. [11] Places like Cape Town tried to implement aquaculture and are now producing more than two tons of fish annually. [12]
Successful implementation of aquaculture would mean it is a sustainable and functioning method of aquaculture use. Implementation requires careful and concise planning with emphasis on environment preservation, rather than destruction. In Brazil, the government has been promoting studies on zoning and demarcation of aquaculture parks, which could, if successfully carried out, make Brazil the largest producers of fish in net-cages in the world. [12]
As urban aquacultures are starting to become more wide spread, especially in coastal areas, it is only logical to observe and study the systems used in the production of the fish and all the other products. There are three systems that differ from one another in the intensity they are managed by. The systems are; extensive, semi-intensive, and intensive. The extensive aquaculture is mainly characterized by increased dependence on natural food in the process of producing the stock (Bunting et al.). The Semi-intensive production, on the other hand, is primarily based on the fertilizer applications; this is done in order to improve the natural food production and to maintaining the use of low-protein supplements (Bunting et al.). As for the intensively managed systems, however, they depend on externally sourced high protein input feed. Also, the by-products and waste resources are utilized and used to produce food of high protein value and level such as tubifex worms and fly larvae to supply aquaculture producers (Bunting et al.). This shows and highlights the different means of production of the urban aquaculture and how they are maintained and integrated in the process of farming the fish and the other products. [10]
There are three general types of aquaculture systems based on the way they are managed. They include extensive, semi-intensive and intensive systems. [13] Extensive aquaculture systems are usually conducted in medium-to-large-sized ponds or water bodies. The fish production depends on the natural productivity of the water, making this system low cost and maintenance. With semi-intensive fish farming, the production of fish per unit is low. However, they tend to be incomplete and are rarely used as a sole food source. Intensive fish farming involves that the quantity of fish produced per unit of rearing area is great. To intensify the culture, production factors have to be controlled to improve the production conditions. [13]
Aquaculture, also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants. Aquaculture involves cultivating freshwater, brackish water, and saltwater populations under controlled or semi-natural conditions and can be contrasted with commercial fishing, which is the harvesting of wild fish. Aquaculture is also a practice used for restoring and rehabilitating marine and freshwater ecosystems. Mariculture, commonly known as marine farming, is aquaculture in seawater habitats and lagoons, as opposed to freshwater aquaculture. Pisciculture is a type of aquaculture that consists of fish farming to obtain fish products as food.
Mariculture, sometimes called marine farming or marine aquaculture, is a branch of aquaculture involving the cultivation of marine organisms for food and other animal products, in seawater. Subsets of it include, fish farms built on littoral waters, or in artificial tanks, ponds or raceways which are filled with seawater. An example of the latter is the farming of plankton and seaweed, shellfish like shrimp or oysters, and marine finfish, in saltwater ponds. Non-food products produced by mariculture include: fish meal, nutrient agar, jewellery, and cosmetics.
Fish farming or pisciculture involves commercial breeding of fish, most often for food, in fish tanks or artificial enclosures such as fish ponds. It is a particular type of aquaculture, which is the controlled cultivation and harvesting of aquatic animals such as fish, crustaceans, molluscs and so on, in natural or pseudo-natural environments. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a species' natural numbers is generally referred to as a fish hatchery. Worldwide, the most important fish species produced in fish farming are carp, catfish, salmon and tilapia.
Aquaponics is a food production system that couples aquaculture with hydroponics whereby the nutrient-rich aquaculture water is fed to hydroponically grown plants.
Marine shrimp farming is an aquaculture business for the cultivation of marine shrimp or prawns for human consumption. Although traditional shrimp farming has been carried out in Asia for centuries, large-scale commercial shrimp farming began in the 1970s, and production grew steeply, particularly to match the market demands of the United States, Japan and Western Europe. The total global production of farmed shrimp reached more than 1.6 million tonnes in 2003, representing a value of nearly 9 billion U.S. dollars. About 75% of farmed shrimp is produced in Asia, in particular in China and Thailand. The other 25% is produced mainly in Latin America, where Brazil, Ecuador, and Mexico are the largest producers. The largest exporting nation is India.
Inland saline aquaculture is the farming or culture of aquatic animals and plants using inland sources of saline groundwater rather than the more common coastal aquaculture methods. As a side benefit, it can be used to reduce the amount of salt in underground water tables, leading to an improvement in the surrounding land usage for agriculture. Due to its nature, it is only commercially possible in areas that have large reserves of saline groundwater, such as Australia.
Tilapia has become the third most important fish in aquaculture after carp and salmon; worldwide production exceeded 1.5 million metric tons in 2002 and increases annually. Because of their high protein content, large size, rapid growth, and palatability, a number of coptodonine and oreochromine cichlids—specifically, various species of Coptodon, Oreochromis, and Sarotherodon—are the focus of major aquaculture efforts.
Integrated multi-trophic aquaculture (IMTA) is a type of aquaculture where the byproducts, including waste, from one aquatic species are used as inputs for another. Farmers combine fed aquaculture with inorganic extractive and organic extractive aquaculture to create balanced systems for environment remediation (biomitigation), economic stability and social acceptability.
Fishing in India is a major sector within the economy of India contributing 1.07% of its total GDP. The fishing sector in India supports the livelihood of over 28 million people in the country, especially within the marginalized and vulnerable communities. India is the third largest fish producing country in the world accounting for 7.96% of the global production and second largest producer of fish through aquaculture, after China. The total fish production during the FY 2020-21 is estimated at 14.73 million metric tonnes. According to the National Fisheries Development Board the Fisheries Industry generates an export earnings of Rs 334.41 billion. Centrally sponsored schemes will increase exports by Rs 1 lakh crore in FY25. 65,000 fishermen have been trained under these schemes from 2017 to 2020. Freshwater fishing consists of 55% of total fish production.
Aquacultural engineering is a multidisciplinary field of engineering and that aims to solve technical problems associated with farming aquatic vertebrates, invertebrates, and algae. Common aquaculture systems requiring optimization and engineering include sea cages, ponds, and recirculating systems. The design and management of these systems is based on their production goals and the economics of the farming operation.
A raceway, also known as a flow-through system, is an artificial channel used in aquaculture to culture aquatic organisms. Raceway systems are among the earliest methods used for inland aquaculture. A raceway usually consists of rectangular basins or canals constructed of concrete and equipped with an inlet and outlet. A continuous water flow-through is maintained to provide the required level of water quality, which allows animals to be cultured at higher densities within the raceway.
Microponics, in agricultural practice, is a symbiotic integration of fish, plants, and micro-livestock within a semi-controlled environment, designed to enhance soil fertility and crop productivity. Coined by Gary Donaldson, an Australian urban farmer, in 2008, the term was used to describe his innovative concept of integrated backyard food production. While "microponics" had been previously used to refer to an obscure grafting method in hydroponics, Donaldson's application of the term was derived from the amalgamation of micro-livestock (micro-farming) and the cultivation of fish and plants, a practice commonly known as aquaponics.
Organic aquaculture is a holistic method for farming fish and other marine species in line with organic principles. The ideals of this practice established sustainable marine environments with consideration for naturally occurring ecosystems, use of pesticides, and the treatment of aquatic life. Managing aquaculture organically has become more popular since consumers are concerned about the harmful impacts of aquaculture on themselves and the environment.
Aquaculture is the farming of fish, shellfish or aquatic plants in either fresh or saltwater, or both. The farmed animals or plants are cared for under a controlled environment to ensure optimum growth, success and profit. When they have reached an appropriate size, they are harvested, processed, and shipped to markets to be sold. Aquaculture is practiced all over the world and is extremely popular in countries such as China, where population is high and fish is a staple part of their everyday diet.
Offshore aquaculture, also known as open water aquaculture or open ocean aquaculture, is an emerging approach to mariculture where fish farms are positioned in deeper and less sheltered waters some distance away from the coast, where the cultivated fish stocks are exposed to more naturalistic living conditions with stronger ocean currents and more diverse nutrient flow. Existing "offshore" developments fall mainly into the category of exposed areas rather than fully offshore. As maritime classification society DNV GL has stated, development and knowledge-building are needed in several fields for the available deeper water opportunities to be realized.
Saltwater aquaponics is a combination of plant cultivation and fish rearing, systems with similarities to standard aquaponics, except that it uses saltwater instead of the more commonly used freshwater. In some instances, this may be diluted saltwater. The concept is being researched as a sustainable way to eliminate the stresses that are put on local environments by conventional fish farming practices who expel wastewater into the coastal zones, all while creating complementary crops.
Valliculture is an ancient fish culture practice that originated in the Mediterranean region namely the Adriatic and Tyrrhenian coasts. People exploit the seasonal migrations of some fish species from the sea into the lagoons by preventing the fish from returning to the sea. The term now applies to fish culture in coastal lagoons or brackish water bodies based on seasonal migrations of fish. The ancient practice of valliculture is not as prominent as before; however, modern aquaculture heavily relies on the venerable principles of the system.
Recirculating aquaculture systems (RAS) are used in home aquaria and for fish production where water exchange is limited and the use of biofiltration is required to reduce ammonia toxicity. Other types of filtration and environmental control are often also necessary to maintain clean water and provide a suitable habitat for fish. The main benefit of RAS is the ability to reduce the need for fresh, clean water while still maintaining a healthy environment for fish. To be operated economically commercial RAS must have high fish stocking densities, and many researchers are currently conducting studies to determine if RAS is a viable form of intensive aquaculture.
Integrated mangrove-shrimp (IMS) aquaculture is a sustainable farming system used as one of the measures for mangrove rehabilitation and can be described as a method of organic aquaculture. Silvoaquaculture or silvofisheries are also terms used to define this farming practice where mangrove trees are planted alongside shrimp ponds allowing for profitable net income from shrimp farming, as it replicates a more natural habitat.
Aquaculture in the Philippines makes up a substantial proportion of the overall output of Philippine fisheries. Aquaculture has a long history in the archipelago, with wild-caught milkfish being farmed in tidally-fed fish ponds for centuries. Modern aquaculture is carried out in freshwater, brackish water, and seawater throughout the country through a variety of methods.