3. Carryi ng Capacity Analysis

In Brazil, the classification of water bodies and environmental guidelines for such classification, as well as the conditions and standards for effluent discharge into water bodies are recommended and established by the National Environment Council (CONAMA) through Resolution 357 of 17 March 2005. The standards of water quality established in this resolution set individual limits for each substance in each class of water that must be achieved or maintained in the long run.

The National Water Agency—ANA, an agency of the Ministry of Environment responsible for regulating the use of water among other attributions, based on CONAMA’s resolution, is responsible for determining the amount of phosphorus that can be released to the environment through the feed in order to ensure the sustainability of the activity. All aquaculture projects in Federal Union waters, whether private or governmental, must be approved by that agency.
To calculate the maximum increment of nutrients from aquaculture, ANA uses the conservative model of Dillon and Rigler (1974) adapted to reservoirs. In aquaculture, ANA estimates a maximum increase of 1/6 of the concentration permitted by CONAMA Resolution 357/2005 for water bodies of Class II, in which the use for aquaculture farming is included.

This corresponds to 5 mg/m3. The other 5/6 would be reserved to other uses that add phosphorus to water, such as the dilution of domestic and industrial sewage, agricultural activity and, of course, natural phosphorus increment.
Thus, each grant issued today includes a maximum annual production of fish, the maximum daily amount of feed given and the maximum daily load of phosphorus added to the water—as well as other items such as the grant’s validity period and the geographical coordinates of the project.
The Ministry of Fishing and Aquaculture is responsible for planning, regulating and monitoring aquaculture activities and for promoting research to improve the carrying capacity calculation method.