A view from the air--Where have the forests gone? (Sierpe River Area, SW Costa Rica)
Farm raised fish that escape their habitat into a larger body of water are dangerous to the native fish that live nearby. After escaping, the farmed fish have the opportunity to mate with native fish when this occurs. When stock escape this negatively affects the gene pool of the wild fish because farm raised fish are not bred for survival. Instead they may be bred for characteristics like size (lb. on scale) and color (fancy fishes) or perhaps another variation of characteristics that seem attractive in the markets. Breeding the fish and plant organisms using a selective method like the one used by aquatic farmers creates a weaker gene pool for the organism overall, because it does not allow the process of natural selection to take place. The environment is completely controlled not allowing the idea of the survival of the fittest to occur. The escaping fish issue has brought on particular guidelines known as “codes of containment”, created by the U.S. Environmental Protection Agency, for aquaculture farmers to follow.
Drug-laced fish foods provide the fish with parasite control. Disinfectants are used to kill bacteria; herbicides are used for killing excess vegetation. Resulting from this, some farmed fish have been discovered to be carrying the same chemical residues of hormones and drugs found in cattle. There are also vaccines given to prevent infections. This naturally creates a completely controllable environment for the fish. Some people consider this a good thing, because of the fishes guaranteed wholesomeness. Others do not consider this good, because it is so unnatural.
Supplying the habitats for a large number of farmed fish in a small place is not
environmentally ideal. It is not an ecosystem that would be naturally supported. It far too compact, and lacking in so much diversity. A massive amount of waste material is created from this habitat. Wastes are created from uneaten fish feed and the high amounts of excreted wastes that go along with densely stocked habitats. The resulting wastes are high in nitrogen and phosphorus and when they are released in rivers or oceans they can cause the growth of algal blooms, which deplete oxygen.
Degradation of the Environment:
Lots of the mangroves that used to exist are no longer around. One major reason is because the habitats are not very “attractive” and another reason is because the habitats are so nutrient rich and create excellent breeding grounds and hatchery environments. As with any other resource that uses the land, there are slash and burn techniques used by some that use up the land quickly and leave it in no shape to still be worked with afterwards.
Health-conscious people are increasing their consumption of fish and shellfish. Ocean fish catches are also declining, so naturally production to fill the demand for these fish is taking place. There is a market for fish not only in the grocery store, but in pet stores too.
A lot of money must go into to starting up an aqua farm. A proper facility for the aquatic organisms to grow in must be built, in a practical area, and it must also follow regulations set by the government. In the South there is a long growing season for aquatic organisms. There are several facilities that can be used for aquaculture: levee ponds, watershed ponds, cages, raceways and flow through tanks, and recirculating systems, of which levee and watershed ponds are the most greatly used. Levee ponds are shallow bodies of standing water created by humans that must have less than 5 percent of slope and a soil/clay content of atleast 20 percent. Watershed ponds are built by damming ravines or small valleys. From 5 to 30 acres of watershed is needed to supply the water for one surface acre of pond. These are cheaper to create than levee ponds are, but they are also more risky for the animals and plants living in the habitat, because of less oxygen there. The most important factor in aquaculture is water quality. Dissolved oxygen levels in water can drop quickly and fish suffocate and die. Wastes produced by fish can build up, harm their delicate gills and lead to other problems. That is why fish farmers must learn how to use water quality test equipment.
There are positive changes that are taking place in aquaculture including new methods such as the integration of plants in the farming environment, the use of species such as mussels (that feed on droppings), and the usage of large bags for living species) and capture wastes for collection instead of dispersal. As more time using these methods goes by more safe productivity will take place. Overall, more awareness about the flaws and misuse along with the correct way to aqua farm will be helpful to aqua farmers in the future.
Bardach, John E., John H. Ryther, and Willion O. McLarney. Aquaculture; the Farming and Husbandry of freshwater and Marine Organisms. New York, Wiley-Interscience, 1972.
Lee, Jasper S., and Michael I. Newman. Aquaculture: An Introduction. Danville, IL: Interstate Pub. 1992.
Pillay, T.V.R., Aquaculture and the Environment. New York: Halsted Press, 1992.
Harrell, Jackie, "Florida Aquaculture, Live on the Web!" 25 May, 2000. Online. Internet. March 5, 2003. Available http://www.doacs.state.fl.us/press/2000/05252000.html.
"Global Aquaculture Alliance." Feeding the World through Responsible Aquaculture.
Northwest fisheries Science Center. National Oceanic and Atmospheric Administration.
Environmental Protection Agency Online. http://www.epa.gov/agriculture/anaqupro.html
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