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Fish-Farming to
Protect the Rain Forest

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What's it all about?

In response to destructive slash-and-burn agricultural techniques, farmers in Peru are moving to something called "integrated aquaculture". Fish-farming, using non-destructive organic methods, is providing a source of food and income for Peruvian farmers, without endangering the fragile ecosystem of the Amazon rain forest.

What's So Special About the Rain Forest??

The earth's climate and atmospheric conditions, its variety of soil and water conditions each supporting unique kinds of life and offering different opportunities for human habitation, all depend on a complex interaction among its different environments - deserts, forests, oceans, ice caps, grasslands, wetlands, and so on. The characteristics of any one kind of environment depend on the other environments that surround it, and even on environments hundreds and thousands of miles away.

As much as every single environment contributes in an important way to maintaining life on earth, a good case can be made for the special importance of the tropical rain forest.

In a tropical forest, nature assumes some of its most extraordinary and beautiful forms. But as striking as forest life is to the human eye, its greatest benefits are harder to see. They have to do with the most basic elements of life -- soil, atmosphere, and climate; food, water, fuel and shelter. It's not only the teeming life of the forest that is threatened when the forest is cut down, but life -- including human life -- everywhere on the globe.

Forests once covered six million square miles of the earth's surface. We've lost more than a third of that already, and the rate of destruction is going up. Today, nearly fifty acres a minute are cut down -- an area the size of Great Britain each year.

In the history of the earth, plants were the first organisms on dry land. In order for other life forms to evolve, energy had to be captured from the nonliving environment.

This task fell to the plants, which accomplished it by photosynthesis. Plants capture the sun's energy and use it to produce foods which other organisms consume.

Peru is a land of dramatic contrasts -- from the broad deserts that line the Pacific coast to the fertile valleys along the western slope of the Andes -- to the towering mountains themselves -- to the Amazon basin, which begins in the streams that descend the mountains' eastern slope.

Here, in the Amazon basin, the tropical forest begins. Like others of its kind around the world, the Amazon forest is a fragile and endangered ecosystem.

Genetic Diversity

On average, an acre in a tropical rain forest is home to ten times as many living species as another environment. This means that the genetic material of the tropical rain forest is richer and more diverse than that of any other environment, both within a given species and across the variety of species.

A tropical rain forest is a reservoir of genetic diversity, and as such it is very important for humans. We are more likely to find a valuable new medicine, a new kind of food, or a new pest-resistant or disease-resistant strain of an already familiar food in a tropical rain forest than anywhere else on earth.

Climate Regulation

Tropical rain forests also play a central role in the regulation of the earth's climate, both regionally and globally. They recycle vast amounts of carbon dioxide into oxygen, a process critical to all kinds of life and which, by removing carbon dioxide from the air, tends to cool the earth's average temperature. They recycle rainfall into new clouds, which provide further needed rainfall not only for the rain forest itself but for agricultural regions far outside the forest's borders. Both the cloud cover and the rain also keep temperatures cooler.


Tropical rain forests are the source of many of the world's most important watersheds as well. The water that is not used by the plants and animals of the tropical rain forest or recycled into clouds finds its way into river systems that sustain, by providing water for irrigation, navigation, and drinking, some of the largest concentrations of people on the planet - in South and Southeast Asia, in Africa, and in South America.

The levels at which the tropical rain forest releases water into its rivers, the seasonal rates at which it does so, and the nutrients with which the forest's abundant life fills the rivers are all features of the rain forest that people who live far from the forest itself depend on for their daily survival.

What Are the Dangers to the Rain Forest?

For all its value, the tropical rain forest is one of the most endangered environments on earth. People seek many things in a tropical rain forest, and two of the most widely sought pose deep risks to the forest's survival.

The first of these is wood, which is harvested and sold, usually for export. In part to save money and realize higher profits, and in part because of the very density of a tropical rain forest, such harvesting is typically carried out by bulldozers. In contrast to the selective cutting done in temperate forests, timber harvesting in tropical rain forests usually leaves a barren landscape that has no chance to regenerate itself.

The second threat to the rain forest comes from attempts to convert it to agricultural uses, ranging from small single-family farms to vast cattle ranches run by multinational corporations. Because the nutrients in a tropical rain forest are held mostly in the foliage, these efforts, too, soon leave behind an empty and lifeless terrain. Topsoil in the rain forest is very thin and must be held in place by trees and other forest plants; when those are cleared away the land rapidly becomes eroded, hard and rocky, unsuitable for continued ranching or farming.

Tropical rain forests tend to be located in countries where sources of immediate income are needed, from the individual to the national levels. They are often countries with large populations, whose governments seek to open up new territories where people can get food and livelihood from farming. That desire, and the desire on the part both of private companies and of governments to realize a profit from the forest and its land - either from lumbering or from other activities, such as mining - put the rain forest at risk.

Getting a short-term livelihood or profit from the rain forest can bring troubling long-term consequences. Most rain forest species can live only in the rain forest environment, so the loss of that environment means the loss of the species. Since there are more species in the rain forest than anywhere else, rain forest destruction presents the greatest single danger to genetic diversity in the world today.

Because tropical forests are so dense with plant life, they are often shrouded by clouds. When a stretch of forest is destroyed, the loss of these clouds beings a dramatic increase in rainfall over a wide territory.

When trees are cleared and crops planted, only a season or two of farming is possible. Then the plot is abandoned. All around the world, land cleared in rain forests will never be fertile again: the heavy rains have washed away the topsoil, and the layer below, now exposed to the sun, takes on a brick-like character. Less than one percent of the Amazon basin can support sustained cultivation.

The loss of large amounts of plant material when the rain forest is cut down means less carbon dioxide is taken from the air; in addition, the air gains carbon dioxide when the cleared plant material is burned, which it usually is once the tree trunks have been removed. Both of the processes contribute to the greenhouse effect and add to the possibility that the earth's climate will be disturbed by excessive warming.

The disappearance of root systems means that the abundant rain water cannot be held; this water washes away and adds to the risk of floods. Clearing the forest brings erosion. Erosion is more than a scar on the landscape. It creates silt, which clogs rivers, damages irrigation, and leads to flooding.

The rocky earth that is left behind reflects more light and heat into the atmosphere, adding to the likelihood that the climate will get warmer. The likelihood goes up further when the loss of plant material brings diminished cloud cover. This means not only less cooling but also less rainfall.

Within the rain forest's original boundaries, the process known as desertification results from the loss of clouds, rain, and topsoil; outside the forest's edges, deserts form because clouds and rain that once blew in from within the forest no longer do so.

While there is still some debate over the extent of global warming - it is known that carbon dioxide concentrations in the atmosphere have gone up by one fifth in this century, but the evidence for actual changes in temperature are suggestive but not conclusive - there are well-documented cases of desertification and of flooding due to siltation from a number of rain forest regions that have undergone extensive cutting.

What's it All About?

Many nations are taking steps to protect the tropical rain forests within their borders by creating parks and nature reserves. But it is clear that this kind of action can protect only a fraction of the world's rain forest lands. Maintaining parks and reserves is expensive, especially for governments who are trying to meet the competing needs of other people for income and for land on which to live.

Juan Guevera's job is to help the farmers who live in the area around the city of Pucallpa, in the part of the Amazon Basin that lies in Peru, meet their needs for food and income. For many years, these farmers have relied on a kind of agriculture known as slash-and-burn, which involves burning the rain forest plant cover to create plots for cultivation. Because land cleared in this way is only good for a couple of growing seasons, and because the population in the area is rising rapidly, the net effect of this kind of agriculture is a significant loss of rain forest, and no significant improvement in income or nutrition.

Among the effects of damage to the rain forest in the Peruvian Amazon has been a change in the annual patterns of river flooding, and this change in turn has put the survival of a number of native species of Amazonian fish at risk. They face a further challenge from species introduced for commercial purposes from outside of the Amazon Basin, some of whom are better adapted to the new river patterns. Fish catches from area rivers have declined in recent years.

What is Aquaculture?

Fish-farming, or "aquaculture", is an ancient practice, a means by which many peoples around the world provide for their food and livelihood.

In Pucallpa, Peru, Juan Guevera is engaged in a project that holds the promise of aquaculture playing another role. There, it may contribute to the protection of the fragile ecosystems of the Amazon rain forest.

Like many river basins in the area, the Pucallpa region has attracted tens of thousands of agricultural migrants from the mountains and cities. Mining, timbering, and agricultural projects resulting from the rapid growth of the region are taking a toll on the landscape.

Guevera came to Pucallpa as an agricultural researcher. His job was to advise people on how best to gain a living from the land. But he was uneasy about many of the ways this was being done.

"In this Amazon region, extractive activities have been steadily increasing the scope of their operations. This has caused very serious deforestation. Fish farming, unlike these extractive activities, is different. It can be undertaken in the tropics without any drastic effects on the environment."

So What's the Solution?

In Peru, Juan Guevera has seen deforestation bring many of these problems. The annual floods now come faster and deeper. Nutrients washed away are not replaced, and the river waters themselves grow poorer. The supply of fish during the rainy season drops considerably.

In turning to aquaculture, Guevera and his colleagues were turning to a practice that could feed and employ many of these immigrants -- without damaging the tropical forest.

What is unique about integrated aquaculture is how self-supporting it is. In other parts of the world, fish farming requires expensive grain food. As Guevera explains, that is not the case here:

"The people who are immigrating into this area have not traditionally been fish farmers. So, the scheme we are putting into effect here is integrated with the kind of agriculture they do practice. But, since their traditional farming methods produce few byproducts, and since protein is very expensive, we've integrated animals into the process."

48_OSBS1_Ducks_on_Platform.JPG (19572 bytes)Guevera sought a method that was simple and small-scale, and that used available livestock. Most people in the area already had the few pigs, ducks or chicken that are needed. The animals drop their wastes into the pond from raised platforms. The wastes support a population of plankton, which the fish eat along with insects and leaves.

Such integrated aquaculture keeps farmers' costs low, which is particularly important for farmers living at the rain forest's edge, as the cost of transporting their products to market is likely to be relatively high, due to their distance from urban centers, and therefore they must, in order to be competitive, keep all other costs low.

"These fish are herbivorous species with a short food chain. They grow very quickly on a food base of mainly vegetable products."

The results are indeed dramatic. Annual yield of fish for a two and a half acre pond is 11,500 pounds -- an average of more than thirty pounds per day. This brings nutritional benefits to the family and community, in the form of much-needed protein, and provides a considerable surplus that can be taken to market.

Guevera and the other members of his research team -- called "IVITA" -- work hard to make the fish ponds productive. They determine the ideal balance of animal wastes that go into the pond. They've studied more than three hundred varieties of Amazonian fish in order to find the ones best-suited to this kind of pond. So far, the choices are: the gamitana, the boquichico, and the sabolo.

"The gamitana and sabolo are native species that bring a high price commercially. But since they're migratory species that don't reproduce well in ponds, we're experimenting with artificial reproduction.

For Guevera, it was important to work with species native to this part of the Amazon basin. Imported species might find their way into the Ucayali and other nearby rivers, where they would compete with the native stock.

During the long rainy season, when the swift rivers overflow their banks, the catch from local streams is meager. The cost of fish doubles or triples, and malnutrition is a severe problem. The aquaculture project allows for a steady supply during the entire year.

Guevera, his assistant Guadalupe Contreres, and other members of the IVITA team provide fish fingerlings and plankton to families who want to begin their own fish culture. They provide advice on how to build and maintain the pond. Individual families can manage their own ponds; so far, six families have begun to do so, and their sense of pride and enthusiasm is clear.

The initial costs for the animals, along with the cost of feeding and maintaining them, are very low. A tractor has to be hired for the initial digging. Banks in the area provide loans for this service. Low cost and high productivity are important for the role the Pucallpa project plays in the protection of the forest.

Guevera feels that the small-scale, integrated aquaculture methods developed in Pucallpa can be applied anywhere in the Amazon basin. Deforestation, population growth, and malnutrition occur in many parts of the region.

Integrated aquaculture in the Peruvian Amazon has many benefits. It provides a source of nutrition and of income for farmers who might otherwise engage in a kind of agriculture that would damage the rain forest. A further benefit is that the ponds are helping to maintain the native Amazonian fish species. IVITA monitors and studies the local species, and where appropriate encourages farmers to raise these.

The solution that Juan Guevera and the farmers he works with have developed is part of a growing international consensus about how to keep rain forests alive. In the past, the need to protect an endangered environment almost always led to calls for new parks and reserves – for effectively removing human populations from everyday contact with that environment. It has been and remains politically and economically difficult for struggling countries to do this.

The new consensus is to find a way that people can coexist with the rain forest. One way is to live at its edges and engage in activities that sustain rather than harm the forest. If it can be shown that the long-term benefits of such practices, not just for the rain forest ecology and the global environment, but for the well-being of the people who live in and near the rain forests, outweigh the short-term profits from lumbering, mining and slash-and-burn agriculture, then the rain forests will face a more secure future.

There's abundant reason, based on what we know about the role of rain forests in our global economy, to try to save these precious resources.

The forests are so rich with life that the number of species lost when an area of tropical forest is destroyed is ten times the number lost when other environments disappear.

Near Pucallpa, deforestation endangers jaguars, and threatens the rare pink dolphins that swim in the Ucayali River.

There's also reason to try to save tropical forests on grounds of what we don't know. When we consider all the medical and industrial substances we depend on that come from the rain forests, the odds favor the likelihood that we can derive great benefits from the five out of six species we have not yet even identified.

The Amazon forest needs protection, to be sure, but it cannot simply be fenced off. Its future can also be made more secure when the expanding populations at is edges find ways to prosper without harming the forest. The work of Juan Guevera and the IVITA team allows the people of Pucallpa to do just that.

Integrated aquaculture is a way that families can produce their own food with minimal damage to the fragile environment around them.

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