Cooling of Andaman causes sightings of hungry rare sea animals

The Monkey Dive Thailand page, which has over 51,000 followers and over 50,000 likes, suggests that the so-called Indian Ocean Dipole phenomenon has caused the temperature of the Andaman Sea to fall, prompting rare fishes and sea animals to come to feed on more fertile foods.

To be more specific, the page said, the Andaman Sea is under the effect of the “positive” Indian Ocean Dipole, which causes the layer of cooler water to rise closer to the sea surface. That layer is called a “thermocline”, according to the page.

The IOD is a climate pattern, and it swings like a pendulum, influencing weather and ocean conditions across the Indian Ocean and beyond. The IOD has two phases – positive and negative.

During the IOD's positive phase, the western side heats up more than usual, while the eastern side cools down. This creates a “tilt” in the ocean’s temperature, like a dip in the middle.

During the negative phase, the temperature pattern flips. The eastern side becomes warmer than usual, while the western side cools.

Monkey Dive Thailand said the positive IOD has caused the thermocline in the eastern Indian Ocean, the area known as the Andaman Sea, to move up to a level of 50 metres from the surface.

The shifting of the thermocline has caused the chilling water from the ocean bed to flow to the islands in the Andaman, and particularly to Mu Ko Similan National Park, which is on the edge of the continent.

When the chilling water flew into the Andaman, plankton and other foods came with it, and thus attracted rare fish and sea animals, according to Monkey Dive Thailand.

The peak of the positive dipole is around September to November each year in the area, and should end around January.

Recent sightings of rare sea animals included a Snaggletooth Shark, which was spotted at the northern point of the marine park on December 10.

The web page of Mu Ko Similan National Park also reported the sighting of an Eagle Ray in the park on December 6, following another eagle ray that was spotted near Ko Miang on November 10.

On November 7, the park also reported that three False Killer Whales were spotted near Ko Ta Chai in the marine park area.

The diving page added that the positive IOD also has drawbacks because too cold water can kill corals.

A recent survey found that the Similan sea temperature has dropped to 20 Celsius degree, so divers should wear a wetsuit while diving, the page warned.