Environmental Impacts of Aquaculture

Impacts of Aquaculture

It is hoped that aquaculture production can increase to offset the inevitable decline in capture fishery and many are hopeful that it can be done in an environmentally friendly manner. Due to bad management practices and poor design, some of the early aquaculture ventures have proven to be almost equally as destructive as capture fishing. Some of the main concerns of aquaculture are habitat destruction and the release of large quantities of nutrient and chemical pollution into the ecosystem. It is important to note that some aquaculture projects have successfully integrated themselves into the environment, sometimes improving the quality of the environment by removing excess pollution. First the damages that can result from aquaculture will be discussed, followed by a description of how, in some cases, aquaculture has proven beneficial to the local ecosystem.

Most people are familiar with the effects of habitat destruction and chemical pollution as they are popular subjects of the media, however, a brief description is in order. Chemical pollution results from the leakage or dumpage of biologically disruptive chemicals into the environment. These chemicals eventually work their way through the food web damaging whatever population they enter, or offsetting the delicate balance of the ecosystem. Habitat destruction results from human development that changes the landscape or other factors of the ecosystem. Often the new environment created by humans cannot sustain the life forms that had originally lived on it. These animals or plants are forced to relocate or die. In severe cases of habitat destruction the displaced animals have no where to go and die off. Nutrient pollution results from the release of certain compounds that stimulate the growth of several specific organisms to the detriment of the majority. Nutrient pollution usually results in eutrophication of the body of water and can exacerbate algae bloom problems.

Aquaculture, if not managed and designed correctly can destroy vast quantities of natural biota and release large quantities of nutrients into the surrounding region. As shown in the photo of a fish farm to the right, large quantities of land can be converted into fish ponds, destroying much of the original biota. The shrimp farming industry is notorious for its destruction of mangrove forests.(Click here for a more detailed description of the importance of mangrove forests.) However, the practice of locating shrimp farms in mangrove forests has diminished as it has proven to be a poor site for shrimp culture.

Another danger of aquaculture is the release of excess nutrients into nearby water supplies. Due to the high organism density in the fish ponds high levels of nitrate and phosphate nutrients are created that can leak out into local water supplies and begin the process of eutrophication. Often the eutrophication manifests itself in the form of large algae blooms or the development of deadly organisms such as Pfiesteria which can destroy the local ecosystem.

Despite the dangers of improperly organized aquaculture projects many believe that a properly run program can coexist with the natural ecosystem and still produce large quantities of aquatic products. However , such projects are expensive and most of the damage caused by aquaculture thus far is the result of aquaculture farmers cutting corners where they shouldn't to increase their profit margin. For aquaculture to work an environmentally friendly attitude must be adopted. If aquaculture does live up to its potential it could become one of the world's significant sources of foodstuffs.

Many of the problems outlined above, while, significant do not result from all aquaculture practices. Some cultures, such as those of mollusks and seaweed can actually decrease the pollution concentrations in the region. Mollusk farms and some seaweed farms can remove excess nutrients from a watershed and thus help prevent eutrophication within the water shed. Fish cultures are also used to help reestablish wild populations of decimated species. Sustainable aquaculture is known to be possible because it has been achieved.