China scaled down a rescue effort for crew missing from a capsized fishing vessel, after concluding that very few air pockets remained to keep alive any trapped survivors, state media said on Tuesday.

Seven bodies were retrieved from the fishing vessel, the "Lupeng Yuanyu 028", after it capsized last week in a central area of the Indian Ocean with a crew of 39 aboard, mainland media have said.

The ministries of transport and agriculture, along with authorities in eastern Shandong province, downsized the effort to a 48-hour small-scale investigation from a large maritime search and rescue, CCTV said, citing the transport ministry.

The seven ships operating at the site of the disaster were down from 13 a day earlier. The wrecked hull was drifting slowly northeast, the broadcaster added.

Sri Lankan divers found and recovered remains in the ship's cabin, CCTV said. But it was not immediately clear which of the crew had been found from among those originally on board, made up of 17 Chinese, 17 Indonesians and five from the Philippines.

An analysis of the various factors involved in the disaster showed extremely limited air pockets in the wreck to allow for humans to survive, leading to a preliminary finding that there were no survivors, CCTV said, citing the transport ministry. (Reuters)