Posco said Thursday it has started cultivating sea forests ahead of the Oceans Day, which falls on May 31.

The steelmaker said it has installed 100 Tritons -- the firm’s artificial reef brand made of steel slag -- and 750 Triton blocks approved by the Ministry of Maritime Affairs, in waters off Namyang-ri, southern Ulleungdo, to create a 0.4-hectare sea forest.

The 100 Tritons will be installed on the edge of the sea forest, where seaweed will grow, and 750 Triton blocks will be piled up like mountains in the center, serving as a habitat and breeding ground for fish, Posco said.

Posco said it developed the artificial reef based on steel slag, a byproduct produced during the steel manufacturing process with its research unit Research Institute of Industrial Science & Technology in 2000. It has provided enough free steel slag to make 6,559 Tritons for some 30 sea forests in Korea.

The steelmaker held a ceremony on the day attended by around 20 people, including Ulleung County Gov. Kim Byung-soo, a fishing village chief and fishermen in Namyang-ri and Posco President Jang In-haw.

By Shin Ji-hye (shinjh@heraldcorp.com)