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Environmental impact of Aquaculture
Transcript of Environmental impact of Aquaculture
Attention! Background photo by t.shigesa The Future of Aquaculture Phosphorus
Antibiotics The Environmental impact of aquaculture Digestibility and Availability of Nutrients in Feed Ingredients FORMULATION OF THE ENVIRONMENTALLY FRIENDLY
FEEDS Approaches to Increasing Digestibility
of Dietary Nutrients Dietary Level
Chelation Environmentally friendly feeds 1. Reduce nutrient levels in the diet to the minimum requirement levels for fish.
2. Select highly digestible feed ingredients (avoid ingredients of low digestibility).
3. Process feed ingredients to improve the digestibility or availability of nutrients. Greenhouse gases aren’t as much of a problem, although the energy consumed by fishing boats and by production of fish does contribute to climate change. However, the biggest problem is overfishing. Aquaculture like many other sectors uses natural resources and interacts with the environment. However, aquaculture is increasingly confronted with issues of environmental protection.
WHY? Global harvest of aquatic organisms in million tonnes, 1950–2010, as reported by the FAO Aquaculture the farming of aquatic organisms, including finfish, shellfish (mollusks and crustaceans), and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, and protection from predators. Farming also implies individual or corporate ownership of cultivated stock (FAO, 2000a). Concept of sustainable feeds.
Environmentally friendly feeds have to meet various other standards Fish feeds nowadays have to meet all of these requirements:
maximizing fish growth & fish quality
minimizing feed cost & waste excretion
These requirements are all endless, yet have critical and direct effects for the sustainability and the development of aquaculture for the future In the second half of the twentieth century, however, additional needs have emerged:
to control final product (fish) quality (marketing requirement)
to reduce excretion of wastes (environmental requirement) Earlier in the twentieth century the goals of nutrition in aquaculture were
to develop feeds that support optimum growth of fish (biological requirement)
to use inexpensive feed ingredients whose supply are stable (economical requirement) Error bars indicate standard errors of three replicate tanks. Pretreated (right end columns in the figure) indicates that soybean meal was treated with phytase before mixing with other ingredients (200U phytase/kg soybean meal; equivalent to 100U/kg dry diet, for 24 hours at 50°C or 122°F, pH 5.3, soybean meal/water ratio 2 : 1). The amount of citric acid added was 5% in the diets (dry basis).
Source: Sugiura Phosphorus content in the feces of rainbow trout fed soybean meal-based diet supplemented with varied levels of phytase with/without citric acid. Error bars indicate standard errors of three replicate tanks. The apparent availability of phosphorus in the diet was 70.6% (0% citric acid), 90.9% (5% citric acid), and 96.6% (10% citric acid). Source: Sugiura Phosphorus content in the feces of rainbow trout fed fish meal-based diet supplemented with citric acid at 0, 5 or 10% in the diet (dry basis). Concept of Sustainable Feeds the cost of the feed (economical requirement), fish growth, feed efficiency, disease resistance of the fish (biological requirement), and the final product quality and safety (marketing requirement) Ingredient Selection advantages: the supply of plant protein sources is more stable and feasible compared
disadvantages: with animal by-product materials most plant protein sources contain less phosphorus than fish meal
reduction in the growth of fish due to low palatability (low feed intake or the phosphorus content in blood meal is low and the digestibility of protein and the availability of many minerals in it are high) Balanced Formula Protein Levels
Fat Levels (the deficiency in phosphorus increases the retention of dietary fats due to the inhibition of the beta-oxidation of fatty acids)
Carbohydrate Levels (Increasing DE value by increasing digestible carbohydrate may reduce feed intake and reduce growth rate of the fish, especially in carnivorous species) Finishing Feeds Deficiencies of micronutrients in diets do not cause immediate clinical deficiency of fish
Fish can subsist considerable periods using the body store without showing any deficiency signs Quality Assurance The compounds can catalyze the oxidation of fish oil, while others counteract it.
Inorganic copper and iron are known to be strong pro-oxidants for unsaturated fatty acids and for certain labile vitamins, to increase rancidity of dietary fats, and to cause a loss of vitamins in feeds during storage Radar, GPS, and other advanced technology Large fish populations “fishing down the food chain,” As our oceans, lakes, and rivers run out of fish, the alternative is aquaculture, or fish farms. Unfortunately, current aquacultural practices are not environmentally friendly. Fish are crammed together in cages, often swimming around in their own wastes, and given antibiotics to avoid disease. A Dall's Porpoise entangled in a fishing net. NOAA (US Federal Government) photo, public domain.
From http://www.nmfs.noaa.gov/pr/interactions/lof/ e.g.
Farmed salmon has been shown to have high levels of PCBs and insecticides (Hamerschlag); however, its greenhouse emissions are lower than most livestock, at 4.14 kilograms of CO2 equivalent per kilogram of edible salmon (Hamerschlag and Venkat). The main environmental effects of marine aquaculture Biological Pollution Fish for Fish Feeds Organic Pollution
and Eutrophication Chemical Pollution Habitat
Modification Eutrophication is the process by which a body of water becomes enriched with organic material from algae and other primary producers (e.g., photosynthetic organisms). Eutrophication can be stimulated to harmful levels by the anthropogenic introduction of high concentrations of nutrients such as nitrogen and phosphorus. http://www.iatp.org/files/Marine_Aquaculture_in_the_United_States_Enviro.htm Animals and other organisms themselves can be an important form of "pollution." Aquaculture facilities in the United States unintentionally release farmed fish and their parasites and pathogens into the environment. Some of these escaped organisms can harm native fish populations.
Introduced species are animals released through human activities in areas outside their natural range. By feeding on native species or competing with them for food and habitat, introduced fish can reduce levels of biodiversity and even cause the displacement or extinction of native populations
Escapes of native species of farmed fish can also harm wild stocks, particularly when substantial genetic differences exist between the farmed and wild populations. Genetic differences often occur when farmed fish are specifically bred for aquaculture or are moved from one area to another.
Transgenic organisms have genes from other species inserted into their DNA via genetic engineering techniques, usually to introduce or to amplify an economically valuable trait such as faster growth. Farming of transgenic fish will likely heighten concerns about escapes of farmed fish. Scientists have genetically engineered at least 35 species of fish worldwide (Reichhardt, 2000), although no transgenic fish products are yet commercially available (FAO, 2000). In the United States, the company Aqua Bounty Farms™ has applied to the FDA for permission to market genetically engineered Atlantic salmon* (Reichhardt, 2000; Zitner, 2001). These fish have an added growth-hormone gene from chinook salmon that may cause them to grow significantly faster than nontransgenic fish (CEQ, 2000) aquaculture is sometimes promoted as an alternative to capture fisheries, some types of aquaculture use huge quantities of wild-caught fish as feed in the form of fish meal and fish oil, and thus indirectly affect marine ecosystems thousands of miles from fish farms Nutrient pollution. The adverse effects of eutrophication include low dissolved oxygen levels, murky water, death of seagrasses and corals, fish kills, low- or no-oxygen "dead zones," and possibly harmful algal blooms
Nutrient loading from aquaculture can be significant on a local scale. A salmon farm of 200,000 fish releases an amount of nitrogen, phosphorus, and fecal matter roughly equivalent to the nutrient waste in the untreated sewage from 20,000, 25,000, and 65,000 people, respectively (Hardy, 2000) A wide range of chemicals are used in aquaculture, including antibiotics, parasiticides (parasite-killing drugs), pesticides, hormones, anesthetics, various pigments, minerals, and vitamins. Aquaculture will continue to be one of the most viable methods to supply growing world population needs
the challenge to maintain profitability and environmental compatibility is daunting
Growth of aquaculture was fueled initially by governments eager only for economic success, but many governments have started to implement strict regulatory guidelines addressing environmental and social issues to ensure sustainability
Despite such progress, there are still major aquaculture producing countries that do not have appropriate legal frameworks and policies for aquaculture
All to often, governments fail to provide the needed economic, legal, and social support to ensure economic and environmental sustainability
Politically, food production will remain an overriding priority, and aquaculture will continue to grow. Models must be developed to clearly predict whether the socio-economic benefits of aquaculture are worth the environmental cost Like other forms of food production, aquaculture requires space. Predation, or "depredation," is a serious problem at marine aquaculture facilities. In marine netpens, mammals such as seals, sea lions, and river otters often prey on farmed fish, by reaching through the nets and gouging them. Populations of some seals are on the rise, and seal predation at netpens may worsen. Environmental Impact of Aquaculture by G. Dukhta
Msc Animal Nutrition and Feed Safety “The average trawling operation throws 80 to 90 percent of the sea animals it captures as bycatch overboard” (Foer).Indeed, “Many scientists predict the total collapse of all fished species in less than fifty years” (Foer)—the empty ocean is a real possibility. World Aquaculture Production by Species in 2006 World Salmon Culture Production by Country in 2006 World Shrimp Aquaculture Production by Country in 2006 World Aquaculture Production by Continent in 2006 World Tuna Aquaculture Production by Country in 2006 Many governments promote aquaculture for foreign exchange earnings, income, and employment generation. Aquaculture development in the world has been closely associated with trade. Although seafood trade has been dominated by three species: shrimp, salmon and tuna, shrimp is a typical species produced in the south and exported to the north. This sea foam is abnormal. It is dense and greasy and it coagulates and separates like oil on water. It is not light and fluffy and full of air like bubble bath, like normal sea foam that forms from water and air.
It is an industrial pollutant from a fish farm in Port Mouton Bay that also contains chemical contaminants like toxic copper. It is full of mucus from sick fish that have vomiting and diarrhea from feed that is too oily, as farmers try to pump them full of fatty oils (to meet consumer demand for "omega oils"). from 22.04.2013