An introduction to integrated farming and the use of seaweeds as biofilters

Abstract

The worldwide increase during the last few years in production levels of one-species aquaculture has generated severe environmental effects and has resulted in a growing concern of society. The characteristic of one-species aquaculture is that it is a very inefficient resource user and generates by-products that affect the sustainability of the environment. Many methods intended to mitigate the impact have been proposed, such as the rotation of cultivation areas, use of ecological feeds, increase of the food conversion index, installation of collecting or diffusion devices under the cages. These solutions imply a net cost increase to the producers. On the other hand, the use of integrated farming techniques could be a means of utilizing the waste products of high trophic cultivated organism by integrating filtering invertebrates and seaweeds, thus not only reducing the environmental impact but also producing an additional income. Of special interest is the use of seaweeds for recycling some dissolved nutrients, in particular nitrogen in the form of ammonium.