BEIJING, March 28 (Xinhua) -- The manned submersible Jiaolong will conduct scientific trial missions between June and September, an official with the State Oceanic Administration (SOA) announced on Thursday.

The four months of missions, which will include research in the South China Sea and the northeast Pacific Ocean, mark the start of a five-year trial period for the Jiaolong before it starts regular operation, said Jin Jiancai, office director of the China Ocean Mineral Resources Research & Development Association under the SOA.

The Jiaolong completed a record dive of 7,062 meters in the Pacific Ocean's Mariana Trench in June 2012, demonstrating that it has the ability to allow China to conduct deep-sea scientific research and resource exploration in 99.8 percent of the world's oceans.

"During the missions, we will make use of the Jiaolong's unique capabilities and technical excellence to obtain high-quality deep-sea information and samples," Jin said.

However, the official revealed that the Jiaolong is not yet ready for regular operation, as its mother ship has yet to be built and its oceanauts and maintenance team still need training.

Jin said more efforts will be made to domestically produce spare parts for the sub, adding that a national deep-sea base for the sub is still in the design stage.

According to Jin, the difficulty of the missions will increase gradually, with safety being the top priority.

Also on Thursday, Jin revealed that the association will send three research vessels on a 240-day-plus mission in the Indian and Pacific oceans this year.

Using high-tech equipment such as deep-sea remotely operated vehicles, the research will focus on poly-metallic sulfides, cobalt-rich crusts, deep-sea genetic resources and a survey of the deep-sea environment, according to Jin.

"The international seabed situation is complicated and changing. Our oceanic work involves heavy responsibilities," Jin said.

Jin said the association will strive to win the approval of the International Seabed Authority for Chinese seabed mining applications.