The eastern coastal province of Shandong plans to expand its artificial reefs to 3,000 hectares from 550 hectares over the next three years, buoyed by marked increases in fish stock yields since it first implemented the project in 2005.

The man-made reefs were first laid two years ago in six pilot zones on the coastal seabed of the Yellow Sea and Bohai Sea to rehabilitate fish stocks in the inshore area, which had been drastically reduced by pollution and over-fishing.

The project, which focused on areas near the cities of Rizhao, Weihai and Yantai at a cost of 160 million yuan (21.6 million U.S. dollars), currently has a total coverage of 551 hectares.

"We saw algae clumps prosper on the man-made reefs last year, and the amount of aquatic resources finally soared this year," said Wang Shutian, an official in charge of marine fishing in Shandong.

The reefs ensured harvests from the sea areas rose by 225 tons, equivalent to 30 million yuan in value, according to the provincial marine fishing department.

In the pilot zone in Yantai, the average haul from every 100 square meters of sea water was only 0.48 kg before the building of the reef. The amount rose to 52 kg this year, more than 100 times higher. Meanwhile, the species of fish rose from five in 2005 to 28 this year, said Wang.

Wang said the government would earmark 45 million yuan to launch the 10 new artificial reefs, but they would need additional private investment of 105 million yuan (14 million U.S. dollars) of investment.

In the past four decades, the fish stocks along the 3,000-km long coast of Shandong, has declined dramatically. The annual prawn haul dropped from more than 30,000 tons in the early 1970s to about 1,000 tons in the last decade.

Artificial reefs were first built by some fishermen to grow shrimp, crab and shellfish when they realized their offshore fishing hauls were shrinking.

They were surprised to find fish stocks grew substantially in the artificial environment, said Wang.

Wang said that marine and fishing authorities in Shandong had invited experts to help designate favorable locations along the provincial coastline to build the new reefs.

"Factors such as geology, tide and shipping lanes, as well as the original ecological environment, are all crucial for the reproduction of sea creatures in the reef area," said Wang.