"This is the Chinese naval escort task force. Please call on Channel 16 if you require assistance."

That announcement, in Chinese and English, is now familiar to merchant vessels sailing through the Gulf of Aden and the waters off the coast of Somalia.

For the past eight years, whenever a ship has radioed an SOS, the Chinese naval escort task force has come to the rescue.

In April, the guided-missile frigate CNS Yulin of the 25th Chinese naval escort task force received a message that pirates in the Gulf of Aden had hijacked the OS 35, a bulk carrier from Tuvalu, an island nation in the Pacific Ocean. The Yulin immediately sailed to the area, where 16 special forces personnel boarded the vessel, and rescued 19 sailors.

Escort duties began on Dec 26, 2008, when the first Chinese fleet, consisting of two guided-missile destroyers, the CNS Wuhan and the CNS Haikou, a supply ship, two helicopters, and 800 personnel, sailed from their home port of Sanya, Hainan province, en route to Africa.

Since then, China has sent 26 escort fleets to the region. They have escorted more than 6,400 vessels, half of which belonged to other nations or the World Food Programme.

The Chinese fleet has also searched and deterred more than 3,000 pirate ships and secured "100 percent safety" for both the task force and the ships they escorted.

The task force has participated in other missions, such as the search and rescue operation for Flight MH370, the Malaysia Airlines jet that went missing in 2014, the evacuation of foreign personnel from Yemen in 2015, and more recently, protecting the scientific ship CNS Xiangyanghong 10 when it conducted research in the Indian Ocean.

"These are not easy tasks, given that until recently the Chinese fleet was operating thousands of kilometers from home with no solid logistical support," said Major General Ma Gang, a professor at the People's Liberation Army National Defense University.

In July last year, China opened its first overseas logistic supply base in Djibouti, an African country on the shores of the Indian Ocean.

"The base will ensure the Chinese navy's effectiveness in future escort, peacekeeping and humanitarian missions in Africa and West Asia," Ma said.

However, the Gulf of Aden covers about 530,000 square kilometers, and Somalia has Africa's second-longest coastline - more than 3,000 km - second only to Madagascar.

Up to 95 percent of European Union goods and 20 percent of global trade pass through the Gulf of Aden every year, according to data from the Maritime Security Center, part of the EU Naval Force.

"China has actively participated in escort missions, fulfilling its international obligations as a responsible major power," said Zhang Junshe, a senior researcher at the Naval Military Studies Research Institute of the People's Liberation Army.

"These missions will enhance the training of Chinese Navy personnel and their reputation, as well as deepening cooperation with our naval counterparts from other countries," he said.