Aquaculture , also known as aquafarming , is farmed fish, crustaceans, mollusks, aquatic plants, algae and other organisms. Aquaculture involves the cultivation of freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the harvesting of wild fish. Marga cultivation refers to aquaculture conducted in the marine environment and underwater habitats.
According to the Food and Agriculture Organization (FAO), aquaculture "is understood to mean the agriculture of aquatic organisms including fish, molluscs, crustaceans and aquatic plants.This implies some form of intervention in the maintenance process to increase production, such as ordinary stocking, feeding, etc. Agriculture also implies individual or corporate ownership of cultivated stocks. "The reported output from global aquaculture operations in 2014 supplies more than half of fish and shellfish consumed directly by humans; However, there is a problem about the reliability of the reported numbers. Furthermore, in current aquaculture practices, the product of several pounds of wild fish is used to produce a pound of fish that is like a salmon.
Certain types of aquaculture include fish culture, shrimp culture, oyster cultivation, marine aquaculture, algae (seaweed farming), and ornamental fish cultivation. Specific methods include aquaponics and integrated multi-trophic aquaculture, both of which integrate fish culture and aquaculture.
Video Aquaculture
History
Gunditjmara indigenous peoples in Victoria, Australia, may have raised eel as early as 6000 BC. The evidence shows they developed about 100 km of volcanic floodplains around Lake Condah into a duct and dam complex, and used a wicker trap to catch eels, and preserved them for eating throughout the year.
Fish cultivation operates in China around <2000/BC>. When the water recedes after a river flood, some fish, especially goldfish, trapped in the lake. Early aquaculture feeds their mothers using nymph and silkworms, and eats them. A beneficial genetic mutation of the goldfish led to the emergence of carp during the Tang dynasty.
Japan cultivates seaweed by providing bamboo sticks and, later, oyster nets and shells serve as a retaining surface for spores.
The Romans kept fish in ponds and farmed oysters in the beach lagoon before 100 AD.
In central Europe, early Christian monasteries adopted Roman aquaculture practices. Aquaculture spread in Europe during the Middle Ages as far from the coast of the sea and large rivers, fish had to be salted so they did not rot. Transport improvements during the 19th century made fresh fish readily available and inexpensive, even in rural areas, making cultivation less popular. Fish farms of the 15th century in the Trebon Basin in the Czech Republic are preserved as UNESCO World Heritage Sites.
The Hawaiians built a fish pond. An outstanding example is the "Menehune" fish pond dating from at least 1,000 years ago, in Alekoko. Legend has it that it was built by Menehune mythical dwarves.
In the first half of the 18th century, German Stephan Ludwig Jacobi experimented with external fertilization of brown trout and salmon. He wrote the article "Von der kÃÆ'¼nstlichen Erzeugung der Forellen und Lachse". In the last decade of the 18th century, oyster farming has begun in the estuary along the Atlantic Coast of North America.
The word aquaculture appeared in a newspaper article in 1855 regarding the ice harvest. This also appears in the description of sub-agricultural agriculture practices on land at the end of the nineteenth century before being associated primarily with the cultivation of plant and aquatic species.
In 1859, Stephen Ainsworth of West Bloomfield, New York, began an experiment with brook trout. In 1864, Seth Green had established a commercial hatchery operation in Caledonia Springs, near Rochester, New York. In 1866, with Dr.'s involvement W. W. Fletcher from Concord, Massachusetts, an artificial fish hatchery is underway in Canada and the United States. When Dildo Island fish hatchery opened in Newfoundland in 1889, it was the largest and most advanced in the world. The word aquaculture was used in the description of hatchery experiments with cod and lobster in 1890.
In the 1920s, American Fish Culture Company of Carolina, Rhode Island, founded in the 1870s was one of the leading trout producers. During the 1940s, they have perfected the method of manipulating the day and night cycles of fish so that they can artificially lay eggs about a year.
The Californians harvested the wild seaweed and tried to manage supplies around 1900, then labeled it a source of wartime.
Maps Aquaculture
21st-century practice
Harvesting stagnation in wild fisheries and the excessive exploitation of popular marine species, combined with the demand for high-quality protein, encourages aquaculturists to tame other marine species. At the beginning of modern cultivation, many are optimistic that the "Blue Revolution" can occur in aquaculture, just as the 20th century Green Revolution has revolutionized agriculture. Although terrestrial animals have long been domesticated, most species of seafood are still caught from the wild. Concerned about the impact of increasing demand for seafood in the world's oceans, prominent sea explorer Jacques Cousteau wrote in 1973: "With an enlarged human population on earth to feed, we must move into the sea with new insights and new technologies."
Approximately 430 (97%) of the species cultivated in 2007 were domesticated during the 20th and 21st centuries, where an estimated 106 came in the decade to 2007. Given the long-term importance of agriculture, to date, only 0.08% of ground plant species known and 0.0002% known terrestrial animal species, compared with 0.17% of known marine species and 0.13% of known marine species. Domestication usually involves about a decade of scientific research. Cultivating aquatic species involves less risk to humans than land animals, who take large casualties in human life. Most human diseases come from pets, including diseases such as smallpox and diphtheria, which like most infectious diseases, migrates to humans from animals. No human pathogens have comparable virulence emerging from marine species.
Biological control methods for managing parasites have been used, such as cleanser fish (eg lumps and wrasse) to control sea lice populations on salmon farms. Models are used to assist spatial planning and fish pond location determination to minimize impact.
The decline in stocks of wild fish has increased the demand for cultivated fish. However, searching for an alternative source of protein and oil for fish feed is needed so that the fish farming industry can grow sustainably; otherwise, it is a big risk for excessive forage exploitation.
Another recent issue following the 2008 ban on organotin by the International Maritime Organization is the need to find compounds that are environmentally friendly, but still effective, with antifouling effects.
Many new natural compounds are discovered each year, but producing them on a scale large enough for commercial purposes is almost impossible.
It is likely that future developments in this field will depend on microorganisms, but greater funding and further research is needed to address the lack of knowledge in this field.
Group of species
Aquatic plants
Microalgae, also referred to as phytoplankton, microfit, or planktonic algae, constitute the majority of cultivated algae. Macroalgae commonly known as seaweed also have many commercial and industrial uses, but because of their size and special requirements, they are not easily cultivated on a large scale and most often taken in the wild.
Fish
Aquaculture is the most common form of aquaculture. This involves keeping fish commercially in tanks, fish ponds, or sea cages, usually for food. A facility that releases teenage fish into the wild for recreational fishing or to supplement the natural number of a species commonly referred to as a fish hatchery. Around the world, the most important fish species used in aquaculture are, in order, carp, salmon, tilapia, and catfish.
In the Mediterranean, light bluefin tuna netted in the sea and pulled slowly toward the shore. They are then interned in the offshore cages where they are planted for the market. In 2009, researchers in Australia managed for the first time to persuade southern bluefin tuna to breed in landlocked tanks. Southern bluefin tuna is also caught in the wild and fattened in a fish cage grown in South Spencer Bay, South Australia.
A similar process is used in the salmon farming section of the industry; teenagers are taken from hatcheries and various methods are used to assist them in their maturation. For example, as stated above, some of the most important fish species in the industry, salmon, can be grown using a cage system. This is done by having netted nets, preferably in open waters that have strong flow, and feeding the salmon mixture of special foods that help their growth. This process allows for the growth of fish throughout the year, so the harvest is higher during the correct season. Additional methods, known sometimes as farms, have also been used in industry. The marine farms involve keeping the fish in the hatchery for a short time and then releasing them into the ocean waters for further development, where fish are recaptured when they are grown.
crustacea
Commercial shrimp cultivation began in the 1970s, and production grew sharply afterwards. Global production reached more than 1.6 million tonnes in 2003, worth about US $ 9 billion. About 75% of cultivated shrimp are produced in Asia, especially in China and Thailand. The other 25% is produced mainly in Latin America, where Brazil is the largest producer. Thailand is the largest exporter.
Shrimp farming has shifted from its traditional small-scale form in Southeast Asia into a global industry. Technological advances have led to ever increasing densities per unit area, and sires are sent around the world. Almost all shrimp cultivated are penaeids (ie, shrimp from the Penaeidae family), and only two species of shrimp, Pacific white prawns and gigantic tiger shrimps, covering about 80% of all shrimp cultivated. The monoculture industry is highly vulnerable to disease, which has wiped out shrimp populations throughout the region. Increased ecological problems, recurrent epidemics, and pressure and criticism from both non-governmental organizations and consumer countries led to changes in industry in the late 1990s and generally stronger regulation. In 1999, the government, industry representatives and environmental organizations initiated a program aimed at developing and promoting more sustainable farming practices through the Seafood Watch program.
The cultivation of freshwater prawns has many characteristics with, including many problems with, the cultivation of the lobsters. This unique problem is introduced by the life cycle of the major species development, the giant river shrimp.
The annual global production of freshwater shrimp (excluding shrimp and crab) in 2003 was about 280,000 tons, of which China produced 180,000 tons followed by India and Thailand with 35,000 tons each. In addition, China produces about 370,000 tons of Chinese river crabs.
Molluscs
Sea shells consist of various types of oysters, shellfish, and shellfish. These bivalves are filter and/or deposit feeders, which depend on the primary production of the ambient rather than the input of fish or other feed. Thus, shellfish culture is generally regarded as benign or even beneficial.
Depending on the species and local conditions, bivalve molluscs are planted on shore, in longline, or suspended from rafts and harvested by hand or by dredging. In May 2017 the Belgian consortium installed the first of two experimental farms experiments at a wind farm in the North Sea.
Abalone farming began in the late 1950s and early 1960s in Japan and China. Since the mid-1990s, the industry has been increasingly successful. Overfishing and hunting has reduced the wild population to the extent that abalone farms now supply most of the abalone meat. Sustainable farming mollusks can be certified by Seafood Watch and other organizations, including the World Wildlife Fund (WWF). WWF started the "Aquaculture Dialogue" in 2004 to develop performance-based and measurable standards for responsible farming seafood. In 2009, WWF established the Aquaculture Supervisory Board with the Netherlands Sustainable Trade Initiative to manage global standards and certification programs.
After trials in 2012, a commercial "marine farm" was established in Flinders Bay, Western Australia, to lift abalone. This farm is based on an artificial reef consisting of 5000 (In April 2016) a separate concrete unit called abitats (abalone habitat). The 900Ã, kg abitats can host 400 abalone each. This reef is seeded with young abalone from a hatchery on land. Abalone eats seaweeds grown naturally in abitats, with enrichment of the bay ecosystem also resulting in a growing number of dhufish fish, pink snapper, wrasse fish, and Samson fish, among other species.
Brad Adams, of the company, has emphasized similarities with wild abalone and the distinction of coastal-based fisheries cultivation. "We are not aquaculture, we are gardening, because once they are in the water, they take care of themselves."
Other groups
Other groups include water reptiles, amphibians, and various invertebrates, such as echinoderms and jellyfish. They are separately illustrated in the upper right part of this section, as they do not contribute enough volume to be clearly displayed on the main graph.
Commercially harvested echinoderms, including sea cucumbers and sea urchins. In China, sea cucumbers are cultivated in an artificial pond of 1,000 hectares (400 ha).
Worldwide
In 2012, the world's total fishery production is 158 million tons, where aquaculture contributes 66.6 million tons, about 42%. Worldwide fisheries growth rates have persisted and are rapid, averaging about 8% per year for more than 30 years, while extracting from wild fisheries] have been essentially flat over the last decade. The aquaculture market reached $ 86 billion in 2009.
Aquaculture is a very important economic activity in China. Between 1980 and 1997, the China Fisheries Bureau reported, aquaculture harvests grew at an annual rate of 16.7%, jumping from 1.9 million tonnes to nearly 23 million tonnes. In 2005, China accounted for 70% of world production. Aquaculture is also currently one of the fastest growing food production areas in the US.
About 90% of all US shrimp consumption is farmed and imported. In recent years, salmon aquaculture has become a major export in southern Chile, especially in Puerto Montt, the fastest growing city in Chile.
A United Nations report titled The World of Fisheries and Aquaculture released in May 2014 maintains fisheries and aquaculture supporting the livelihoods of about 60 million people in Asia and Africa.
National laws, regulations and management
The laws governing aquaculture practices vary widely in each country and are often not strictly regulated or easily traced. In the United States, terrestrial and near-shore aquaculture is regulated at federal and state levels; however, no national law regulates offshore aquaculture in the US exclusive economic zone waters. In June 2011, the Ministry of Commerce and National Oceanic and Atmospheric Administration issued a national fisheries policy to address this issue and "to meet the growing demand for healthy seafood, to create jobs in coastal communities, and restore important ecosystems." In 2011, Congresswoman Lois Capps introduced the National Sustainable Offshore Aquaculture Act of 2011 to establish a regulatory and research program for sustainable offshore cultivation in the exclusive US economic zone "; However, the bill was not passed into law.
Exceeded reporting
China dominates the world in its reported aquaculture output, reporting a total output that is twice that of the rest of the world put together. However, there are some historical issues with the accuracy of China's return.
In 2001, fisheries scientists Reg Watson and Daniel Pauly expressed concern in a letter to Nature that China has reported its capture of illegal fisheries in the 1990s. They say that it makes it seem that global catches since 1988 are increasing every year by 300,000 tons, whereas it actually shrinks every year by 350,000 tons. Watson and Pauly suggest this may be related to Chinese policy in which the economic entity that monitors the economy is also tasked with increasing output. Also, until recently, the promotion of Chinese officials was based on increasing production from their own regions.
China denies this claim. The official Xinhua News Agency quoted Yang Jian, director general of the Ministry of Agriculture's Fisheries Bureau, saying that Chinese figures "are basically right". However, the FAO accepts there are problems with the reliability of China's statistical returns, and for periods of data treated from China, including aquaculture data, apart from the rest of the world.
Aquaculture method
Mariculture
Mariculture refers to the cultivation of marine organisms in seawater, usually in coastal waters or sheltered offshore. Marine fish farming is an example of marine aquaculture, and so is marine crustacean farming (such as shrimp), molluscs (like oysters), and seaweed. Salmon and Atlantic molluscs for example are famous in the US.
Mariculture can consist of raising the organism in or in an artificial cage as in a floating net for salmon and shelves for oysters. In the case of closed salmon, they are fed by the operator; oyster shelves filter baits on naturally available foods. Abalone has been planted by eating artificial seaweeds that grow naturally in the reef unit.
Integrated
Multi-trophic integrated aquaculture (IMTA) is a practice in which the by-product (waste) of a species is recycled to become input (fertilizer, food) for others. Aquaculture fed (eg, fish, shrimp) is combined with organic extraction and organic extractive (eg, shellfish) cultivation to create a balanced system for environmental sustainability (biomitigation), economic stability (product diversification and risk reduction) and social acceptance (preferably practice management).
"Multi-trophic" refers to the incorporation of species from different trophic or nutritional levels in the same system. This is one of the potential differences from the practice of ancient water polyculture, which may be a co-culture of different fish species from the same trophic level. In this case, these organisms all share the same biological and chemical processes, with few synergistic benefits, potentially causing a significant shift in the ecosystem. Some traditional polyculture systems may, in fact, incorporate greater species diversity, occupy multiple niches, as a broad culture (low intensity, low management) within the same pool. The term "integrated" refers to the more intensive cultivation of different species in proximity to one another, linked by the transfer of nutrients and energy through water.
Ideally, the biological and chemical processes in the IMTA system must be balanced. This is achieved through the selection and proportion of different species that provide different ecosystem functions. The cultured species are usually more than just biofilters; they are crops that can be harvested from commercial value. A functioning IMTA system can result in greater total production based on reciprocal benefits for coordinated species and improved ecosystem health, even if individual species production is lower than in monocultures during short-term periods.
Sometimes the term "integrated aquaculture" is used to describe monoculture integration through water transfer. However, for all intents and purposes, the terms "IMTA" and "integrated aquaculture" differ only in the level of description. Aquaponic, fractionate cultivation, integrated aquaculture farming systems, integrated peri-urban-aquaculture systems, and integrated aquaculture-aquaculture systems are another variant of the IMTA concept.
Netting material
Various materials, including nylon, polyester, polypropylene, polyethylene, plastic-coated welding wire, rubber, patented rope products (Spectra, Thorn-D, Dyneema), galvanized steel and copper are used for nets in cage farms worldwide. All of these materials are selected for a variety of reasons, including design feasibility, material strength, cost, and corrosion resistance.
Recently, copper alloys have become an important mesh material in aquaculture because they are antimicrobial (ie, they destroy bacteria, viruses, fungi, algae, and other microbes) and hence they prevent biofouling (ie, accumulation, adhesion, and growth of microorganisms undesirable plants, algae, tube worms, barnacles, mollusks, and other organisms). By inhibiting microbial growth, the copper alloy cultivation avoids costly clean changes required with other materials. The growing resistance of organisms to copper alloys also provides a cleaner and healthier environment for aquaculture to grow and develop.
Problem
If undertaken without consideration for potential local environmental impacts, aquaculture in inland waters can result in more environmental damage than wild fisheries, albeit with the waste generated per kg on a global scale. Local concerns with aquaculture in inland waters may include waste handling, antibiotic side effects, competition between farm animals and wildlife, and the introduction of potential invasive plant and animal species, or foreign pathogens, especially if untreated fish are used to feed more valuable. carnivorous fish. If non-local live bait is used, aquaculture can introduce animal plants. Improvements in methods resulting from progress in research and the availability of commercial feed have reduced some of these concerns since their prevalence was greater in the 1990s and 2000s.
Fish waste is organic and consists of nutrients needed in all components of aquatic food webs. Aquaculture in the ocean often produces higher concentrations of ordinary fish waste. Waste collects on the seabed, destroying or eliminating life that lives below. Waste may also decrease dissolved oxygen levels in the water column, placing further pressure on wild animals. An alternative model for food added to the ecosystem, is the installation of artificial reef structures to enhance the available habitat, without the need to add more than feed and nutrition. It has been used in abalone "farms" in Western Australia.
Fish oil
Tilapia from aquaculture has been shown to contain more fat and a higher ratio of omega-6 to omega-3.
Impact on wild fish
Some species of carnivorous and omnivorous fish fish are fed wild forages. Although carnivorous fishes represent only 13 percent of aquaculture production by weight in 2000, they represent 34 percent of aquaculture production by value.
The agriculture of carnivorous species such as salmon and shrimp causes high demand for forage fish to match the nutrients they get in the wild. Fish do not actually produce omega-3 fatty acids, but instead accumulate them from consuming the microalgae that produce these fatty acids, as well as forage fish such as herring and sardines, or, as with fatty predatory fish, such as salmon, by eating prey fish that have collected omega-3 fatty acids from microalgae. To meet this requirement, more than 50 percent of world fish oil production is fed to cultivated salmon.
Cultivated salmon consume more wild fish than they produce as the final product, although production efficiency increases. To produce a pound of farmed salmon, a product of some pounds of wild fish is given to them - this can be described as a "fish-in-fish-out" (FIFO) ratio. In 1995, salmon had a FIFO ratio of 7.5 (meaning 7.5 pounds of wild fish feed required to produce 1 pound of salmon); in 2006, that ratio fell to 4.9. In addition, the growing portion of fish oil and fish meal comes from the residue (a by-product of fish processing), rather than a dedicated whole fish. In 2012, 34 percent of fish oil and 28 percent fish meal comes from residues. However, fish and oil flour from residues, rather than whole fish, have different compositions with more ash and less protein, which can limit their potential use for cultivation.
As the salmon farm industry grows, more wild forages are needed for feed, as the world's seventy-five percent of the world's monitored fisheries are near or have exceeded the maximum sustainable yield. Extraction of industrial scale wild forage fish for salmon cultivation then affects the survival abilities of wild predator fish that depend on them for food. An important step in reducing the impact of cultivation on wild fish is to shift the carnivore species to the plant-based diet. Salmon feed, for example, has gone from containing only fish meal and oil to 40 percent of plant protein. USDA has also experimented with using wheat-based bait for farmed trout. When properly formulated (and often mixed with fishmeal or oil), plant-based feeds can provide the right nutrition and the same growth rate in carnivorous fish farming.
Another impact of aquaculture production on wild fish is the risk of fish coming out of the coastal cages, where they can interbreed with their wild counterparts, diluting wild genetic stocks. Missed fish can become invasive and competing native species.
Coastal ecosystem
Aquaculture poses an important threat to coastal ecosystems. About 20 percent of mangrove forests have been destroyed since 1980, partly because of shrimp farming. An expanded cost-benefit analysis of the total economic value of shrimp farming built in the mangrove ecosystem found that external costs were much higher than external benefits. Over four decades, 269,000 hectares (660,000 hectares) of Indonesia's mangrove forests have been converted to shrimp ponds. Most of these farms are abandoned within a decade due to the buildup of toxins and the loss of nutrients.
Pollution from aquaculture aquaculture
Salmon farms are usually located in pure coastal ecosystems that then pollute them. A farm with 200,000 salmon takes out more dirt than a city of 60,000 people. This waste is discharged directly into the surrounding aquatic environment, not treated, often containing antibiotics and pesticides. "There is also heavy metal accumulation in benthos (seafloor) near salmon farms, especially copper and zinc.
By 2016, mass fish killings have affected salmon farmers along the coast of Chile and wider ecology. Increased production of aquaculture and associated wastes are considered to be contributing factors to mortality of fish and molluscan.
Aquaculture cages are responsible for the enrichment of the water nutrients in which they are established. This results from fish waste and feed input not eaten. The most feared elements are nitrogen and phosphorus that can increase algal growth, including harmful algae that can be toxic to fish. Flushing time, current velocity, distance from the shore and water depth are important considerations when finding sea cages to minimize the impact of nutrient enrichment on coastal ecosystems.
The extent of pollutant influence from aquaculture to seawages varies depending on where the cage is located, which species are stored, how crowded the stocked cages are and what fish are fed. Key species-specific variables include the conversion ratio of species food (FCR) and nitrogen retention. Studies prior to 2001 determined that the amount of nitrogen included as lost feed to the water and seabed column due to waste varied from 52 to 95%.
Genetic modification
This type of salmon called AquAdvantage salmon has been genetically modified for faster growth, although it has not yet been approved for commercial use, due to controversy. The modified salmon combines growth hormone from Chinook salmon that allows it to reach full size in 16-28 months, instead of 36 months normal for Atlantic salmon, and when consuming 25 percent less feed. The US Food and Drug Administration reviews the AquAdvantage salmon in an environmental assessment plan and specifies that it "will not have a significant impact (FONSI) in the U.S. environment."
Ecological benefits
While some forms of aquaculture can damage ecosystems, such as shrimp farming in mangroves, other forms can be very beneficial. Shellfish cultivation adds substrate filtering capacity to the environment that can significantly improve water quality. One oyster can filter 15 gallons of water a day, eliminating microscopic algae cells. By removing these cells, the shell removes nitrogen and other nutrients from the system and retains it or releases it as waste sinking to the bottom. By harvesting these shells the nitrogen they retain is completely removed from the system. The cultivation and harvest of seaweed and other macroalgae directly remove nutrients such as nitrogen and phosphorus. Repackaging of these nutrients can ease the eutrophic, or nutrient-rich condition, known as low-soluble oxygen which can reduce the species diversity and abundance of marine life. Eliminating algae cells from water also increases light penetration, allowing plants like eelgrass to rebuild themselves and further increase oxygen levels.
Cultivation in a region can provide an important ecological function for the population. The shell bed or cage can provide habitat structure. This structure can be used as a shelter by invertebrates, small fish or crustaceans to potentially increase abundance and preserve biodiversity. Increased shelters increase the stock of small game and crustaceans by increasing the chances of hiring which in turn gives more prey to higher trophic levels. One study estimated that 10 square meters of oyster can increase ecosystem biomass by 2.57 kg. The shells that act as herbivores will also be preyed on. This drives direct energy from the primary producer to a higher trophic level that potentially jumps out at some very expensive trophic leap that will increase the biomass in the ecosystem.
Animal welfare
As with land animal farming, social attitudes affect the need for humane practices and regulations in marine animals cultivated. Under the guidelines recommended by the Animal Welfare Animal Welfare Council, good animal welfare means fitness and well-being in the physical and mental state of animals. This can be defined by Five Freedoms:
- Free from starvation & amp; thirst
- Free from inconvenience
- Free from pain, illness, or injury
- The freedom to express normal behavior
- Free from fear and distress
However, the controversial issue in cultivation is whether marine fish and marine invertebrates are really alive, or have the perception and awareness to experience suffering. Although no evidence of this has been found in marine invertebrates, recent studies have concluded that fish do have nociceptors to feel dangerous stimulation and are very likely to experience pain, fear and stress. Consequently, welfare in cultivation is directed at vertebrates; especially fish.
General welfare issues
Wellbeing in fish farming can be affected by a number of problems such as density of spread, behavioral interaction, disease and parasitism. The main problem in determining the cause of welfare disorder is that these problems are often interrelated and affect each other at different times.
Optimal dispersion density is often defined by the carrying capacity of the dispersed environment and the amount of individual space required by fish, which is very species specific. Although behavioral interactions such as shoaling can mean that high stocking density is beneficial for some species, in many species of high density density cultivation may be of concern. Crowds can limit normal swimming behavior, as well as increase aggressive and competitive behavior such as cannibalism, feed competition, territoriality and hierarchy of domination/subordination. This could potentially increase the risk of tissue damage from abrasion from fish to fish contact or fish-to-cage contact. Fish can suffer from reduced food intake and food conversion efficiency. In addition, high density can lead to insufficient water flow, creating inadequate oxygen supply and disposal of waste products. Dissolved oxygen is essential for respiration and concentration of fish below the critical level can cause stress and even lead to asphyxia. Ammonia, a nitrogen excretion product, is highly toxic to fish at an accumulated level, especially when oxygen concentrations are low.
Many of these interactions and effects cause stress on the fish, which can be a major factor in facilitating fish diseases. For many parasites, infestation depends on the host mobility rate, host population density and host defense system vulnerability. Sea lice are a major parasite problem for fish in cultivation, high amounts cause skin erosion and bleeding, gill congestion, and increased mucus production. There are also a number of prominent viral and bacterial pathogens that can have severe effects on internal organs and the nervous system.
Improving welfare
The key to improving the well-being of marine cultured organisms is to reduce stress to a minimum, because prolonged or repetitive stress can cause a variety of adverse effects. Efforts to minimize stress can occur throughout the cultural process. As long as it grows, it is important to keep stock density at appropriate levels specific to each species, as well as separate class sizes and gradations to reduce aggressive behavioral interactions. Keeping net and cages clean can help positive water flow to reduce the risk of water degradation.
Not surprisingly diseases and parasites can have a profound effect on fish welfare and it is important for farmers not only to manage infected stock but also to implement disease prevention measures. However, prevention methods, such as vaccination, can also cause stress due to extra handling and injection. Other methods include adding antibiotics to feeding, adding chemicals to water for bathing treatments and biological controls, such as using a wrasse cleanser to remove fleas from cultured salmon.
Many steps involved in transportation, including catching, seizing food to reduce contamination of transport water faeces, transferring to transport vehicles via net or pump, plus transport and transfer to the delivery location. During water transport must be maintained at high quality, with regulated temperature, adequate oxygen and minimal waste products. In some cases, anesthesia can be used in small doses to calm the fish before transport.
Aquaculture is sometimes part of an environmental rehabilitation program or as an aid in preserving endangered species.
Prospects
Global wild fisheries are declining, with valuable habitats such as estuaries in critical condition. Aquaculture or fish-eating fish, like salmon, does not help the problem because they need to eat products from other fish, such as fish meal and fish oil. Studies have shown that salmon farming has a large negative impact on wild salmon, as well as forage fish that need to be caught to feed them. Higher fish in the food chain are less energy efficient food sources.
Regardless of fish and shrimp, some cultivation businesses, such as seaweed and mivalat bivalve meals such as oysters, shellfish, mussels and shellfish, are relatively benign and even restorative environments. Filter-feeder filters out pollutants and nutrients from water, improves water quality. Seaweed extracts nutrients such as inorganic nitrogen and phosphorus directly from water, and filter-feeding mollusks can extract nutrients as they feed on particulates, such as phytoplankton and detritus.
Some fishing aquaculture cooperatives benefit to promote sustainable practices. The new method reduces the risk of biological and chemical pollution through minimizing fish stress, cutting down netpens, and applying Integrated Pest Management. Vaccines are increasingly being used to reduce the use of antibiotics for disease control.
Aquaculture systems on land, facilities using polyculture techniques, and appropriate facilities (eg, offshore areas with strong currents) are examples of ways to manage negative environmental effects.
Recirculating aquaculture systems (RAS) recycle water by circulating through a filter to remove fish debris and food and then circulate it back into the tank. This saves water and the collected waste can be used in compost or, in some cases, can even be treated and used on land. While RAS is developed with freshwater fish in mind, scientists associated with the Agricultural Research Service have found a way to raise salted fish using RAS in low-salt waters. Although saltwater fish are raised in offshore cages or are caught with a net in water that typically has a salinity of 35 parts per thousand (ppt), scientists are able to produce healthy pompano, saltwater fish, in a tank with salinity of only 5 ppt. Commercialization of low salinity RAS is predicted to have positive environmental and economic effects. Unwanted nutrients from fish food will not be added to the ocean and the risk of transmission of diseases between wild fish and those raised on farms will be greatly reduced. The price of expensive saltwater fish, such as pompano and combia used in the experiment, will be reduced. However, before all this can be done, researchers must study every aspect of the fish life cycle, including the amount of ammonia and nitrate that fish will tolerate in water, what feeds the fish during each stage of its life cycle, the level of supply that will produce healthy fish , etc.
About 16 countries now use geothermal energy for aquaculture, including China, Israel, and the United States. In California, for example, 15 fish farms produce tilapia, bass and catfish with warm water from underground. This warm water allows fish to grow throughout the year and matures faster. Collectively, this California farm produces 4.5 million kilograms of fish every year.
See also
- Agroecology
- Alligator farm
- Aquaponik
- The blue revolution
- Copper alloys in aquaculture
- Maggots are used as food for fish
- Fish hatchery
- Fisheries science
- Industrial aquaculture
- List of water animals harvested by weight
- Circulating the aquaculture system
Source of the article : Wikipedia
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