As the Spanish entered the capital city of Tenochtitlan they were astounded at the many marvels of the city but one of the things that most caught the eyes of the foreigners was the extensive plant growth on the lake surrounding the city. These images were describe the among the first recorded descriptions of large scale mariculture. Mariculture, or aquaculture, refers to the rearing of the aquatic organisms under controlled or semicontrolled conditions. Although there is a simple difference between the two, aquaculture generally refers to the exploitation of freshwater fish and mariculture more generally refers to the culture and farming of marine organisms. Simply put mariculture is underwater agriculture. There are many possibilities for the realm of mariculture, it has the potential to be a great help in the production of the food supply in the world.
Mariculture is not a new development in mankinds history but it is a largely ignored form of food production. In a broad sense mariculture includes the rearing of tropical fishes, the production of minnows, koi, and goldfish; the culture of sport fishes for stocking into farm ponds, streams, reservoirs, and even the ocean; production of animals for augmenting commercial marine fisheries; and the growth of aquatic plants. Mariculture is a myriad of possibilities that involve organisms and the seas.
The history of mariculture can be traced back way into the past, the Greeks and Romans were known to have fattened fish in ponds and Egyptian carvings suggest that the Egyptians may have practiced it as well. So we know that the potential for the exploitation has been there for a very long time. Why then has this type of food procurement not been used more extensively? There can be a few good reasons for this such as the availability of technologies, the difficulty of harvesting the seas, and the knowledge of the workings of the sea in order to fully use the capabilities of the ocean. We now have the technology, knowledge, and capability to successfully implement large scale mariculture. Historians say that agriculture made it possible for man to grow and expand as it has done over the last few thousand years so now one can wonder what the future holds if and when mariculture is implemented into the everyday workings of society. Could it be the next giant leap for mankind?
There are many different methods to mariculture. For the most part mariculture entails the confinement of fish to earth ponds, concrete pools, or cages suspended in open water. In these enclosures, the fish can be supplied with adequate food and protected from natural predators. Some of the most common methods for mariculture are transplantation, hatchery stocking, and enclosures and retainers. Transplantation involves the movement of fish populations from a good fishing area to a location that does not exhibit a great fishing catches. In this way areas of low fish concentration are injected with an influx of fish that help to make the average much higher and thereby bring the overall population to a higher state.
The next method of mariculture is hatchery stocking this process happens when people create a safe environment such as tanks, pools, or concrete or earth ponds into which they pour fish eggs. These eggs are cared for and are provided with the essential things such as nutrients and correct temperatures in which to thrive. The fish are born and raised to a certain stage and then are moved to open waters or such places as lakes, streams, and ponds. In this way these habitats are provided with ample supplies of fish and other marine organisms. Another method involves the use of enclosures and retainers. This certain method can be described in three separate ways, natural feed, supplemental feed, and no natural feed. The natural feed method works by separating the desired fish and the food providers of the fish from there predators in there own natural waters by the use of netted embayments and cages, thereby allowing the provider to grow and multiply in its own habitat and this in turn allows the fish to multiply. The second way is supplemental feed and this method works by isolating fish in tanks or concrete ponds. In these tanks or ponds fish are reared through the use of supplemental feeds along with natural feed that is pumped in from the sea. This allows the fish to have a lot of food supply making sure the fish get nice and fat for the market that they are being primed for. The third method works much like the second involving the tanks and ponds but this time there is no natural feed pumped in instead fertilizers take the place of natural feed along with the supplemental feed that is provided to the fish. Examples of these types of mariculture include young oysters and clams that can be moved from areas where they settled to more favorable areas to fatten for market appeal. Another common technique is to enclose oysters or mussels in mesh containers, attach the containers to ropes, and suspend the ropes beneath floats. Suspended and protected this way, the shellfish can mature away from predators. Algae are also cultured. These algae are often used as protein supplements in foods. One such example is the red algal seaweed called nori, this is especially popular in Japan.
At the present rate of population growth it is estimated that humans will soon run out of areas that will be able to produce enough food to provide for the entire population of earth. Therefore it would make sense to turn to the ocean for help in this regard especially after one considers that the oceans cover 70% of the planets surface. The oceans have often been seen as an endless source of protein that is available to the worlds population only if it can be properly harvested. Mariculture had been proposed as a means of supplementing natural marine and freshwater productivity, and has actually increased to the point where it may account for nearly 15% of the plants and animals harvested from water. Under the right circumstances, densities of animals that can be maintained per unit volume are higher in mariculture systems than those found in nature. This presents an interesting point since we see that it is plausible to create an environment in which food production is maximized. This also brings into focus the need to further develop these ideas and technologies to help foster the kind of production that will soon be needed. There are however problems with mariculture just as there are with agriculture. One such problem is the availability suitable, nonpolluted waters that can successfully harvested. So it is imperative that our coastal waters are preserved not only for health and environmental reasons but also because soon enough it will become important to produce large quantities of food from the ocean and we will not be able to do so if we do not have the water space for the suitable production of mariculture.
Mariculture presents some advantages over traditional fishing methods and also over agriculture. The advantages of mariculture over traditional fishing include the efficiency involved in the cultivation of the fishes, the quantity of the food that it can potentially produce, and maricultures potential for enhancing the natural ecosystem. The efficiency of mariculture is obvious since it is much easier to cultivate a species of fish rather than going around and trying to locate and catch the fish. Mariculture provides an opportunity to create an environment in which the product is kept stationary and its diet can be controlled and in this way the fishes safeness can not be questioned. The second advantage is the sheer quantity of food that can be potentially produced. New technologies and rearing methods help to establish the species and to help them to survive diseases and to allow them to produce more food. The ocean is very large and in its confines are a multitude of foods that can easily help to greatly reduce the world hunger problem. Fish protein is a great source of the essential proteins needed by most starving peoples. The last advantage over normal fishing methods lies in the fact that mariculture rather than exploiting existing fish stocks, aquatic husbandry can be used to supplement depleted resources.
Mariculture also has a few advantages over agriculture. Such benefits include the availability of areas for harvest and physical constraints. Agricultural expansion has been made stagnant because of the lack of land available to help produce the required food. Because of this constraint agricultural growth is seriously impeded. The lands that are still available are questionable because of their origins and their anticipated ability to sustain large scale food production for extended periods of time. Unlike agricultural expansion, cultivating fishery products will not create severe additional strains on terrestrial resources. The area of cultivation in mariculture is generally higher than that of agriculture. Another advantage of mariculture is the simple physical constraints on dry land. In the sea there is a three dimensional area that is available for harvest instead of a simple 2 dimensional one. In the sea three dimensional space allows for wider use of the area and thereby allowing a significant increase in the sheer volume of product produced.
Currently there are many organisms that are farmed from the sea. These include seaweeds, oysters, clams, mussels, scallops, abalones, shrimps, and certain fishes such as salmon and trout. Each type of organism has its own distinct way of being reared and grown to produce maximum food product. These organisms all will be very valuable because as each day passes it seems to become more and more clear that mariculture is the way to go in the future. These organisms represent only a little bit of the food available to be farmed, as time passes we learn more and more about new species with the potential for great food sources.
The future of mariculture seems very bright since there is such a big demand for cheap food and that demand will only keep growing. The potential for the growth of the industry is so large it is baffling. However there are still issues that will present a great deal of problems for the development of this mariculture. Legal issues concerning the viability of using drugs and enhancers in the rearing of the organisms. Also advances in science will have to be made in order to help accommodate the sicknesses that afflict mariculture organisms. Humans will have to learn when and how apply the new technologies that seem to be helping to create new system of growing and protecting the desired organisms.
Over all mariculture is a very potentially useful tool which must be examined and studied in more detail.
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2) Shupe, Steven J. Coastal Aquaculture. Oregon State University Press. Printed in
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4) National Research Council. Marine Aquaculture. National Academy Press. Washington D.C. 1992
5) Iversen, E.S. Farming the Edge of the Sea. The Whitefriars Press Ltd. Printed in London. 1976
6) McVey, James P. Handbook on Mariculture: Vol 1. CRC Press. Printed in Austin, Texas. 1983