Aquaculture   

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Many people are now pointing to the farming of fish, shellfish and aquatic plants as the solution to the world's food problems, most often in systems that combine either 2 or all 3 in a single system. These people note that there are several advantages of water as a growth medium. For instance, aquatic animals can convert more of their food into growth since most of them do not need to support their weight. Most fish do not spend energy to regulate their body temperature. In addition, water is a three-dimensional growing space, so yields per unit area can be quite high when compared to land-based farming.

However, great care needs to given in regards to selecting the fish species to be cultivated. If this is not done, the ecologic advantage may be lost. First of all, it is best to select fish that require no meat or fish products in their diets. Top-level carnivores (most salmon species) for example depend on fish feed of which a portion is usually derived from wild caught fish (anchovies, menhaden, etc.) This offcourse reduces the ecologic advantage severely.^[1] Another issue is that the fish selected (especially when using offshore fish cultivation) should be a native species in that area. Selecting a suitable species (ie common carp) and paying attention that the subspecies is native (ie Cyprinus carpio carpio) for use in a location as Europe is thus vital.^[2] Note btw that most commercially cultivated fish is often not native (most cultivated species worldwide are carp, salmon and tilapia, African catfish, eel, pike, ...)^[3]

The possible advantages of aquaculture have given it the label of an "appropriate technology." But just as solar energy technology can include solar-paneled satellites beaming microwave energy to earth, so aquaculture can be approached from a number of technological starting points. Many appropriate technology aquaculture groups in the United States are working with extremely high densities of organisms in recirculating water systems. Some examples of these "intensive" designs are basement fish tanks, backyard fish farms, dome ponds and greenhouse ponds. Most of these require careful biological monitoring and management (because a small problem in the system can kill all of the fish), and the economics are not yet acceptable.

While the work is certainly important to our urban areas, where little space is available, the high capital and material requirements of such aquaculture strategies make them much less relevant to the developing countries. In fact, many people are convinced that the key to large-scale aquaculture development in the United States as well lies in the enormous potential of farm ponds and reservoirs used for irrigation, fire protection, recreation, livestock watering, etc. Throughout the world, these unused or poorly managed lakes, ponds, streams and rivers represent a vast resource of harvestable waters. At the same time, they are subject to a wide variety.of other uses. As we manage these water resources, our goal must be expanded from short-term production to long-term stewardship which integrates all potential needs. There are many examples of aquaculture which include sewage treatment, mosquito control and aquatic weed control. And aquaculture can play a major role in the maximization of traditional fisheries through spawning and ranching techniques - many coastal and inland fisheries are the best producers of cheap protein because the fish raiser does not have to supply the feed.

[edit] Health implications

In some cases, farmed fish have higher concentration of harmful substances.^{[verification needed]please expand} This is generally not a problem when fish is an occasional meal, but needs to be watched carefully when fish is a staple. The solution to this is better farming practices, with careful monitoring of inputs.

[edit] References

This page includes content from David Bartecchi of Village Earth.