Beijing, May 12 (IANS): Artificial reefs have been built in northeast China's Bohai Sea over the past seven years in an effort to restore fisheries, authorities said here on Tuesday.

The sea is home to the most polluted coastal waters in China due to decades of waste-dumping and offshore oil development, Xinhua news agency reported.

The Liaoning provincial fishery bureau said on Tuesday that artificial reefs and the release of young fish have helped rehabilitate the sea's fisheries and advance water pollution treatment.

Experts with the bureau explained that artificial reefs can provide favourable breeding and hiding places for fish.

The annual fish haul in the sea has returned to over 10,000 tonnes, nearly the same as 10 years ago. The fishery bureau aims to increase the amount by another 30 percent by 2020.

In addition to increased fish hauls, sea cucumbers, prawns, jellyfish and clams can also be harvested in the reefs.