The major terrestrial ecosystem components include the seagrass beds, seaweeds, coral reefs, mangroves, and tropical rainforests among others.
The aquatic system is composed of 500ha of seaweed algae, marine algae and sea grass. With its 165ha of coral and sea creatures, the island is known as a "kingdom of aquatic animals".
More than 130 species of coral has been identified while the algae, and sea grass species are aplenty. More than 200 species of fish have been recorded together with four species of lobster and 84 species of molluscs. Coral and shoals of colourful fish are seen in the clear fresh water zones. Some of these species are listed in Vietnam's and the World's Red Book of Endangered Species.
Diving has been popular in the area, and offers tourists a clear-sighted visit to the rich local aqua system.
|Into the sea: Steve Reid at a dive training session.
Steve Reid, from the UK, has been an active diving expert in the locality running his Blue Coral Diving Company.
Taking to scuba diving at the age of 17, Reid has dived at 30 locations all over the world including the Caribbean Islands, many spots in Europe, the Canaries, the Mediterranean, Australia and the United States.
"I have dived around 6,500 times, which is a lot," he said.
It was the passion for diving that first drew him to Nha Trang in central Khanh Hoa Province, which hosts one of the most diversified sea ecologies in Asia. He joined a course for professional diving instructors in Nha Trang before deciding to take up a post in a diving company in Hoi An City eight years ago.
"I fell in love with Hoi An right from the beginning," he recalled.
"Diving in Hoi An is fairly new when compared with the rest of Asia, since diving as a sport has made an appearance here only in the past ten years. Hoi An is gradually making a name for itself as a spot for diving all over Asia, and not just in Vietnam. The diving community always tells each other that if they visit Vietnam, they should go diving in Hoi An."
Reid set up his own Blue Coral Diving centre in 2010 to offer courses to both amateur and professional divers, courses for underwater photography and filming, underwater rescue, and even scuba diving tours. The course ranges between two days and two weeks.
"We often train beginners with the most basic skills in scuba diving in a swimming pool first," he said, adding, "When they can control every equipment and get used to the water environment, we take them to the sea."
He said the instructors first bring trainees to the shallow areas. The trainees will dive no deeper than 12m in their first two dives.
|Happy family: Briton Steve Reid and his wife and little daughter. — Photos courtesy of Steve Reid
Reid praised the Hoi An sea for its "strange soft coral reef that cannot be seen anywhere else in Vietnam".
He said Cham Island is an interesting place to dive with some shallow water areas for the beginners and deep water area of 15 metres at the back of the island for professional divers.
"It is a place with variety for everyone, except if you want to dive with a shark. Then it is not the right country," Reid joked.
"There are a lot of attractions in Hoi An," Dimitri Gatin, a Russian tourist said.
"I love diving with Steve. I discovered his passion for scuba diving as well as his love for the sea here through his thorough understanding of the local waters. He also told me a lot about Hoi An. Sometimes, I think that he is an ambassador of this city," Dimitri said.
"Diving is not about money, it is about lifestyle," Steve said.
"We work eight months a year, the work is enjoyable... so it is not hard work. It is a great thing to do for people on their holiday," he said.
"When they say ‘goodbye' with big smiles, we know they have had a good day with us," Reid stressed.
He has got another "anchor" to pin him down to the Cham sea – Pham Thi Ngoc Tuyet, the Vietnamese woman he got married to six years ago. They now have a little daughter.
"He loves our girl," she said about Reid, adding, "He often plays with her on the sand, teaches her how to swim..."
Tuyet helps her husband manage the centre.
"Living in Vietnam I feel a lot of freedom," Reid said.
"The people are good. Everyone is happy and I look forward to each day. The weather is good, the food is good, the country is beautiful... I dive every day. It is a great place to live," Reid said.