The structure of China's marine economy has been optimized over the past five years, with the tertiary industry's share growing by almost 9 percentage points in that period to 56.6 percent in 2017, lawmakers heard on Monday.

　　The marine economy has grown at an average annual rate of 7.2 percent since 2012, and the average annual growth rate for coastal tourism stood at 12.1 percent.

　　The data was presented to the Standing Committee of the National People's Congress, the top legislature, by He Lifeng, head of the National Development and Reform Commission.

　　He also warned that the environmental capacity in coastal areas remains under threat from high-polluting discharges from land areas and sea reclamation.

　　"The large concentration of heavy industries in some coastal areas poses continuous pressure on the ecological environment," He said.

　　Coastal wetland areas have been decreasing, and some marine ecosystems including seaweed and coral are in unhealthy condition, he said, adding that China has occasionally been hit by red tide, which refers to large concentrations of aquatic microorganisms.

　　He said that garbage pollution in the sea has been an emerging problem.

　　While the coastal areas have been overexploited, the deep seas are still underdeveloped, he added.

　　"China has most of its marine industries in its coastal areas, and most activities related to marine development and exploitation also occur in these areas," He said.

　　The country still has limited capability to understand and develop oil and gas, mineral and biological resources in the deep sea, he added.