In the IMTA setting, seawater is recycled and up to 30% of the wild kelp, Ecklonia maxima, consumed by abalone is replaced by Ulva lactuca grown on site in the recirculation system. The overall commercial gain from using an IMTA approach was estimated at between USD 1.1 and 3.0 million per year, including a significant increase in farm profits (USD 200 000 to 700 000). The environmental benefits included the reduction of nitrogen discharges into adjacent coastal waters by 3.7 to 5.0 tonnes per year, the reduction in harvesting of wild kelp beds by 2.2 to 6.6 hectares per year, and the reduction of C02 emissions (reduced pumping needs) by 290 to 350 tonnes per year.