* Farmed fish to exceed captured fish for human use by 2018
* World per-capita fish consumption to reach 19.6 kg in 2021
MILAN, July 9 (Reuters) - Aquaculture output is expected to rise 33 percent over the next decade helping to meet the world's growing demand for fish as healthy and nutritious food gains popularity while fishing stagnates, the United Nations' food agency said on Monday.
World fisheries and aquaculture production is projected to rise to about 172 million tonnes in 2021, 15 percent up from the average level for 2009-2011, the UN's Food and Agriculture Organisation (FAO) said in a report.
A 33 percent surge in output of aquaculture, or farming fish, crustaceans, mollusks and aquatic plants, over the period of 2012-2021 to 79 million tonnes compared with the three percent growth of capture fisheries, it said.
"Aquaculture will remain one of the fastest-growing animal food-producing sectors," the report said.
By 2018, farmed fish is expected to exceed captured fish for human consumption for the first time and its share is seen at 52 percent in 2021.
Fish demand has been on the rise because fish and fishery products represent a valuable source of protein and essential micronutrients for balanced nutrition and good health.
In 2009, fish accounted for 16.6 percent of the world population's intake of animal protein and 6.5 percent of all protein consumed, the FAO said.
World per-capita apparent fish consumption is expected to rise to 19.6 kg in 2021, 16 percent higher than the average level for 2009-2011, but the pace of growth will slow as prices rise, it said.
World trade of fish for human consumption is expected to expand by 25 percent in 2012-2021 and fisheries supply chains would continue to be globalized, with a significant share of total fishery production being exported, the report said. (Reporting by Svetlana Kovalyova; editing by Andre Grenon)