Vietnam's most beautiful coral reefs bleaching due to El Nino

Nguyen Thai, 29, who has been a scuba diving trainer for four years at the Con Dao Dive Center, says Con Dao is the most beautiful location for diving and coral watching in Vietnam, thanks to the excellent conservation efforts.

But things have been changing with the corals bleaching en masse, he says.

Late last month the management committee of the Con Dao National Park said the bleached corals are in Con Son Gulf, Bay Canh Islet Dam Tre Gulf and certain other areas.

In the photo from around a week ago, corals at the Tai Islet can be seen bleached.

A photo of corals off Tai Islet two weeks ago. On the left are corals in the process of becoming bleached. During his dives, Thai has seen several types of corals becoming bleached.

"Having seen the Con Dao corals during their most beautiful days, I'm very sad to see this," he says.

The photo of a sea fan coral taken by Thai at the Bong Lan Islet area two years ago.

Stony corals are usually found in shallow waters, forming reefs; while soft corals can easily be recognized as their features move along with the water currents, according to the Scuba Schools International.

A red lionfish is photographed swimming at a reef at the Bay Canh Islet area in 2022.

Thai says the corals at Con Dao used to be much thicker and more colorful a few years ago.

The Con Dao National Park said bleaching happens due to rising sea temperatures caused by El Nino. The average water temperatures currently are around 32 degrees Celsius, while the ideal temperature range for coral is 24-30 degrees.

Thai says the corals were also bleached last year, and things have worsened this year.

A clownfish is seen swimming near an anemone at the Bay Canh Islet in 2022.

Con Dao District in Ba Ria-Vung Tau Province has 16 islands that span 76 km2. Corals thrive around the Con Dao National Park in an area of around 1,500 ha and comprise around 360 species. Corals dying en masse due to El Nino was also seen in 1998, 2020 and 2016.

An orange clownfish is seen swimming near an anemone at Bay Canh Islet in 2022.

At the islet, people often dive in an area dubbed "Fireworks." On sunny days, in the clear water, the corals often sparkle, resembling fireworks. However, Thai says this can be seen no more due to the bleaching.

Thai says corals around the world are being bleached due to changing weather patterns.

The bleaching severely impacts diving activities at Con Dao, he says.

He adds it will take young, developing corals dozens of years to fully mature like the reefs that are bleaching.