Aquaculture can remediate or pollute the surrounding environment according to the system design. The following indicators were developed to quantify these aquaculture services or disservices to ecosystem integrity. Positive values indicate pollution mitigation, whereas negative values indicate that the aquaculture system causes pollution. Loads are measured in mass. Effluents may be the outlet water from ponds and tanks, or the water after passing through farms comprised of net-cages, pens, long-lines, trays, etc.
1. Eutrophication (EN and EP)
Mariculture: EN = (Load of nitrogen in source water - Load of nitrogen released in effluents) / mass or units produced
Freshwater Aquaculture: EP = (Load of phosphorous in source water - Load of phosphorous released in effluents) / mass or units produced
2. Oxygen depletion (Od)
Od = (BOD5 in source water – BOD5 released in effluents) / mass or units produced
3. Organic Pollution (OP)
OP = (Load of organic matter in source water – Load of organic matter released in effluents) / mass or units produced
4. Siltation (S)
S = (Load of total suspended inorganic solids in source water – Load of suspended inorganic solids released in effluents) / mass or units produced
5. Global Warming (GW)
GW = (Load of greenhouse gases absorbed – load of greenhouse gases released to the atmosphere) / mass or units produced
Greenhouse gases = mass of CO2 + CH4 + N2O, measured in CO2 equivalents
6. General Chemical Pollution (GCP)
GCP = (Load of chemicals in source water – Load of chemicals in effluents) / mass or units produced
Chemical products = mass of herbicides, insecticides, anti-algae, antibiotics, and other chemicals applied
7. Pollution by Heavy Metals (PHM)
PHM = (Load of heavy metals in source water – Load of heavy metals in effluents) / mass or units produced
8. Changing α-biodiversity (CB)
CB = 100*(S-Wd – S-Ws) / mass or units produced
In which:
S-Wd = Shannon-Winner diversity index obtained in a similar place not impacted by the farm
S-Ws = Shannon-Winner diversity index obtained surrounding the farm
The above indicators were successfully validated on different freshwater fish, marine shrimp and bivalve farms in Brazil.