DALIAN, Liaoning - When the mercury hits -5 C, the last thing most of us think about is taking a dip in the ocean.

Yet for Wang Shuhui, a professional diver from Northeast China's Liaoning province, he can barely afford to stay out of the water -- it's his busiest time of year.

Diver Wang Shuhui makes a living by gathering seafood near Zhangzidao Island, Liaoning province. Here he shows the trepang, or sea cucumber, he's just gathered in this photo taken on Dec 19. [Provided to China Daily]

Based on an island near Dalian, Wang dives to the seabed for precious seafood like trepang, a kind of sea cucumber, as well as abalone and sea urchin.

"Chinese people emphasize the importance of taking tonics in winter," Wang said. "Seafood like trepang is one of their favorites."

An Inner Mongolian native, Wang moved to Zhangzidao, an island 56 nautical miles from Dalian, when he was a teenager. Since he was 17, Wang has been working as a diver with Dalian Zhangzidao Fishery Group, an enterprise derived from the island's people's commune set up in 1958.

"We, as citizens on this island, are the biggest shareholders of the company," Wang said.

The whole island relies on sea farming in its surrounding 1,500-sq-km sea area, and this is the peak season.

They grow young scallop, abalone and trepang in hatcheries on the island and then distribute them to the bottom of the sea.

They even divide the seabed into sections to rotate farming and allow for fallow seasons so the environment can restore itself.

Most young residents on the island work at the fishery. Some cultivate seeds on the island, some fish in the ocean, and others work with the company's partners overseas.

Wang chose to become a diver because "it pays the most", at least three times the company average. Last year, Wang earned 181,000 yuan ($27,000).

The 30-year-old brushed off the high risk involved.

"In comparison with the older generation, the risks we face aren't worth mentioning," Wang said, referring to his 80-year-old diving tutor Wang Tianyong.

Wang Tianyong once dove for abalone to be served at the State banquet for former US president Richard Nixon.

Due to limited fishing capacity in the past, only very important people had the privilege of tasting the abalone grown near the island, called the "Pearl of the Yellow Sea".

Two months before the president's visit to China in 1972, Wang Tianyong, then the head of the island's diving team, received an assignment to collect 1,000 kg of abalone for the State banquet.

At that time, the fishermen had no experience finding abalone in winter waters. It took the divers seven days to locate their colony at the bottom of the sea, Wang said.

"The seabed is like a bank with so much precious seafood, and divers are like cashiers. In the next eight days, we withdrew 1,500 kg of abalone from the 'seabed bank'," recalled the former head of the diving team.

In -10 C temperatures, the simply equipped divers risked injury and death. Despite their bodies and hands becoming numb in the cold, they had to return to the deep sea to allow their bodies to slowly readjust if they felt discomfort because of the pressure difference. It was the only method they had at that time.

"Although some of us complained about taking risks for the 'American imperialists', we were proud that our State leaders treated distinguished guests with our seafood," said Wang, who worked as a diver for 23 years. His right leg is now crippled after he suffered from the bends, a kind of occupational disease resulting from rapidly lowering the air pressure surrounding the body.

Compared with the arduous old days, the new generation of divers like Wang Shuhui has more guarantees.

They have professional diving equipment, underwater telephones to stay connected and pressure-relief tanks to tackle the pressure difference.

But as seafood produced by the island has now reached every corner of the world, Wang and his 60 or so fellow divers are busier than their older generation.

Every day, Wang starts working at around 7 am. A boat usually carries three divers, and they work underwater by turns. For each dive, they spend around 25 minutes under the water, during which each can gather around 50 kg of seafood. On average, each might stay underwater from two to six hours a day.

"It's not a heavy job. Sometimes, we can finish the work in the morning and the rest of the day is ours," said Wang.

Wang said he will continue his diving career for another two years. Then he'll have to transfer to another position because the company only allows one to work as a diver for 15 years.

He said he will choose to stay on the island for other work, even though he has managed to purchase an apartment in downtown Dalian.

"I enjoy life here," he said. "You see, we have clear skies, blue sea, soft beaches, delicious seafood, good social order What else do you need?"