Aquaculture refers to the farming of aquatic organisms such as different types of fish, varieties of mollusks, species of crustaceans and plants in both fresh and salt water. As opposed to Agriculture which takes place on land, Aquaculture is so named as it refers to a similar activity carried out in water. Sometimes referred to as Aquafarming, it involves the production under controlled conditions of fish, seaweed, shrimp and other water organisms (Costa-Pierce, 2002, p2).
Aquaculture Black Brawns
Situated in Port Douglas, North Queensland; the Black Brawns Aquaculture project mainly concentrates on the production of prawns. Prawns are mostly produced in large-scale ponds. The process of this production runs 24 hours a day throughout the year. It is a four-stage process that involves hatching, growing, harvesting and processing of the prawns. Given that the prawns feed at night, most of the activities of feeding run between 11 pm to dawn (Anderson Et al, 2006 p 4).
Prawn farming in Australia is a thriving industry that employs 2,800 people directly and indirectly. It produces 3,500 metric tons of prawns annually in farms covering 900 hectares. It raises a total revenue of US$ 47 million (FAO, 2009). Apart from Port Douglas, other mega producing areas in the region are Mackay, Bundaberg and Sunshine Coast. The main species produced are Black Tiger, Banana and Kuruma Prawns. To regulate and manage the affairs of the industry, the Australian Prawn Farmers Association [APFA] was formed in 1993. Through APFA, interests of the farmers are presented to the regional and state government. The organization is also charged with the responsibility of ensuring that high standards of production are adhered to in order to ensure the health and well being of the ever-growing numbers of prawn consumers (Anderson Et al, 2006 p 17).
Other than prawns, aquaculture products include oysters, crabs and fish species. However all these are produced at a lower level than the Prawns.
According to The International Association for Impact Assessment [IAIA], an Environmental Impact Assessment [EIA] is “the process that helps in identifying, predicting, evaluating and mitigating the biological, physical, social, and economic effects of development proposals before major decisions and commitments made” (Costa-Pierce, 2002, p 14). In order for a complete EIA to be carried out factors such as pollution, destruction of plant and animal life and possible diseases must be carried out.
Since the prawns and other aquaculture products are mainly produced in artificial ponds, their impact on the environment is great. First of all, the ponds are constructed using earthmoving machines, which displace large tracts of coastal land destroying the pre-existing ecosystem (APFA, 2001).
Natural plants and terrestrial animals are displaced thus causing adverse imbalances in the ecosystem. As a result, the natural fauna and flora that supports sea and beach life are either out- rightly destroyed or dumped to dry out where they are of no use to their immediate environment. Moreover, the preferred coastal areas are also the popular locations for residential houses. The ideal location of ponds is 1 kilometer from the marine estuarine environment at least 1 meter above the Highest Astronomical Tide [HAT] (Kinsey, 2006). This kind of location ensures that the marine is reachable for the purposes of water pumping in and out of the pond. Keeping above the tide level naturally controls incidences of direct interaction between the prawns and the wild sea. The inhabitants are therefore displaced bringing to the fore issues of compensation and resettlement. The cooperation of these very people is important if the project is to succeed. They are useful in providing labor and logistical support that will oversee the smooth running of the project. All the same, even with their resettlement, the projects greatly disrupts the lives of coastal inhabitants who are moved away from their preferred activities such as fishing and collection of other sea creatures (Anderson Et al, 2006 p 17).
Secondly, the fact that brood stock is mainly acquired from the ocean via diving operations comes with a steep price to sea life. Collecting the prawns or young fish is a massive operation that involves displacement and death of several other species, which are not the primary target of the operations. For the sake of hatchery operations and to ensure genetic diversity, the sea expeditions are regular and massive in nature (APFA, 2001).
Another effect arises from the manner of operation of the prawn farms. The farms are massive and highly mechanized in nature. In Australia, the main form of affluent treatment is re-circulation that involves the pumping of seawater into the pond and subsequently pumping it out again after use and treatment. A typical farm has a water inlet and outlets. Marine water from the estuarine areas in which the farms are situated is pumped into the huge dams using powerful pumping machines (Costa-Pierce, 2002, p 80).
The water pumped in has to have a PH level of 7.5-8.5. However, before it is pumped out again the firm must ensure that the affluent level has been strictly treated to avoid polluting the sea. If this treatment is wrongly done, the result is extensive pollution of the sea through a high turbidity in the water (Nicholsi, 2009). The result is death of sea organisms through low oxygen levels and change in the chemical composition of the water. In addition, the high levels of turbidity have the effect of reducing light penetration into the water causing the destruction of planktons and other plant life. This can be an especially major problem considering that Australia is the leading country in the world in terms of prawn productivity with an average of 4,500 tons per hectare (FAO, 2009). Typical farms must have among their equipment aerators that are used to always control the levels of air in the water. Inlet screens must also be present to help eliminate unwanted dirt and particles that may find their way into the dam in the process of pumping in the water.
The next resultant factor of prawn farming is the uncontrolled spread of diseases that ultimately affect other forms of marine life. Prawns suffer from three main types of diseases. The first is the Mid-Crop Mortality Syndrome, which causes the death of the prawns before they are mature enough for harvesting. The causes of death are many and varied ranging from changes in the chemical composition of the water to temperature changes. Whatever the causes, the other marine animals which feed on the shrimps may themselves get affected sparking of a circle of death up the food chain (Anderson Et al, 2006 p 62).
Another common cause of death is the Bacterial Septicaemia. This is a bacterial disease that attacks the pawns at any stage of their development. The bacteria generally thrive in a warm and polluted environment such as one with high levels of affluent. It is highly dangerous to other marine life including fishes, crustaceans and mollusks. An outbreak among the prawns can therefore have a devastating chain effect as well. The third type is the Haemocytic Entrtitis that also results from pollution of the water. This disease can be spotted by visible spot marks on the surface of the prawns. It is more readily infectious than the other two and therefore has a potential of an overwhelming outbreak (APFA, 2001).
All these diseases must be controlled using a Hazard Analysis Critical Control Point [HACCP] formula. This process ensures that interventions are made at the critical point to control the disease outbreak before it spirals out of control. Each farm must have a Health Management Program [HMP] through the use of biosecurity. This is the process of ensuring that the prawns are safe and healthy and by extension their environment too is well taken care of (Naylor, et al 2001).The ponds must be subjected to regular dry outs and sludge removal after every major harvest. The bottom also needs to be tilled during such dry outs to remove any affluent integrated into the soil.
This ensures that the accumulation of affluent and soil silt is removed. It is a major housekeeping exercise that every owner of a prawn farm must be ready and properly equipped for (Hepburn, 2002, p 41). A Disease Emergency Plan [DEP] must also be written that clearly states what action shall be taken as soon as a situation occurs that may be the beginning of a disease outbreak (Anderson Et al, 2006 p 64). Such a plan must demonstrate that it is designed to be easily understood and implemented by all the people involved. For instance, hands-on workers should know which chemical to apply when particular symptoms are spotted (New, 2002).
The use of chemicals in controlling diseases is another potential hazard to the environment (Diamond, 2005, p 479). Antibiotics may be useful in controlling bacteria, but they also destroy the simpler forms of life in the sea that generally maintain the marine ecological balance by feeding higher forms of life such as fishes, crustaceans and mollusks. To make matters worse, vaccines that can be used in fish farms are not applicable to the rather tiny and biologically different prawns. So he use of the antibiotics is actually inevitable. Uncontrolled use of such medicine may therefore result in the destruction of sea life in a manner that should be strictly avoided. It is imperative to control these chemicals from seeping into the sea through neutralization before the re-circulation of pond water into the sea (APFA, 2001).
Then, the practice of aquaculture is being carried out at the expense of agriculture. Ponds are constructed that range in size from 0.5 hectare Yabbies to large scale Marron Farms of 20 hectares.
This means that aquaculture products have displaced what was once farming land. The fact that aquaculture is growing rapidly therefore means that it will eat more and more into agricultural land. This shall impact negatively on plant and animal production, which form an integral part of the normal human diet. In the Black Brawns project, profit margins have been increasing thus attracting more investment and expansion at a rate of some 2.5% annually. This will impact negatively on normal agricultural production (APFA, 2001).
Another point is that the presence of such large ponds, which consist of water that is primarily stagnant, provides a rich ground for such waterborne diseases. This leads to incidences of diseases such as bilharzia also find their way into the population as a result of activities carried out within or on the periphery of the water bodies. Extreme care must therefore be taken by all those working on these farms to avoid such dangerous eventualities from occurring. This can be done through avoiding direct contact with the water for elongated periods (Diamond, J 2005, p 480). The water here is not that of a swimming pool that circulates in and out every passing second.
Also, the mechanized system of dam construction comes with oil and fume pollution, which in itself destroys fish breeding grounds by changing the ph level of the water and interfering with the oxidation by choking the water levels. Oil and water are immiscible both literally and symbolically in as far as aquatic life is concerned. Other machinery including pumps and generators further compound this problem extreme care must be taken to ensure that they do not kill off the beach and costal sea life with their oil sediments that can greatly accumulate to dangerous levels after many years of use (Diamond, 2005, p 480).
Another of the major concerns is the interaction between wild and farmed varieties of the prawns. The farm varieties generally live in a controlled environment that ensures their survival as compared to the wild ones. There can be levels of interaction and interbreeding which results in inferior breeds that find it hard to survive in the wild. The accelerated increase in the numbers of prawns in the farms whose main drive is to maximize profit also ensures that a lot of feed is deposited into the water. This in itself causes problems since there may not be a high concentration of prawns to feed on it in once released back into the water. As a result, an ecological imbalance is created which results in the food ending up as a pollutant in the water. The hazard of this is that other sea life may be affected by this very feed (New, 2002).
There is also the problem of competition between wild and farmed varieties of the prawns. With the ultimate natural schemer, man, on the side of the farmed varieties, their wild cousins almost always end up the losers. The harvesting process of the breeders for instance may result in massive deaths of the wild prawns and other forms of life caught in the jaws of the capturing process. The farmed ones also get first priority in terms of any feed that may be derived directly from the sea as the wild types are left to fend for themselves in a severely depleted environment. In addition, the huge, well-fed prawns are a physical threat to their wild cousins if let lose into the sea. They are easily dominant and often attack the others easily killing them. Prawns that grow in such protected environments may also easily succumb to diseases that the wild varieties are resistant to causing a reverse effect of death (APFA, 2001).
Any person who interested in carrying out aquaculture must take all the potential impacts into consideration before venturing into the investment. This is the only way of ensuring that they will operate in a clean and well-balanced environment that will cause as little disruption as possible to the environment and the life it supports. Conversely, ignoring the factors often results in the project itself failing in the long run since it is only possible to raise prawns in a good environment.
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