Diving on the wrong side of the Indian Ocean Dipole
The truth behind below average dive conditions in South East Asia in early 2020
Mergui Archipelago, Myanmar
As scuba divers, we are often at the whim of the weather and the ocean. Booking a diving holiday months in advance usually involves research into the seasons and how the weather in the area is during the time we wish to go. Unfortunately, all the research in the world can’t always save you from the guiles of mother nature.
This was the case this year in areas of South East Asia, including the Mergui Archipelago in Myanmar. Normally a trip to this part of the world can be fairly confidently planned to avoid the monsoon or hot seasons to ensure the best diving conditions you can get from November till April. In early 2020, a climatological phenomenon known as an Indian Ocean dipole foiled the plans of many divers in this part of the world.
The Indian Ocean, nestled in between Asia, Africa and Australia, undergoes yearly changes in surface temperature referred to as the Indian Ocean Dipole. This occurrence, discovered in 1999 by climate researchers, alternates between three distinct phases which reoccur every 3 to 5 years. These phases affect the weather systems in the surrounding land and water masses in different ways. The neutral phases bring warm water from the Pacific Ocean through Indonesia and westerly winds along the equator, which keep temperatures relatively normal across the tropical seas. Positive and negative phases tend to create a gradient in temperature across the ocean, affecting surface temperatures and rainfall on either side of the vast body of water.
This year we experienced a particularly strong positive phase the likes of which hasn’t been seen for six decades! Westerly winds became weaker which caused a shift in those warm waters towards the western side of the ocean resulting in little rainfall and the rising of cold waters from the depths in the West coast of Thailand and Myanmar and surrounding seas.
“We’ve never had such cold water in 9 years”, admits Franck Fogarolo, the cruise director of The Smiling Seahorse. With temperatures as low as 20 °C on some dives the guides even loaded the boat with extra shorties. To offer as extra layers, which some divers used on top of their long wetsuits.
While a bit cold, the divers visiting this season did get the chance to see some fairly special creatures. The cold water brought a lot of nutrients to the shallow areas accessible to divers, attracting a lot of marine life not usually visible in the first 30 meters. « We have seen over 40 guitarfish on a single dive in Black Rock in March 2020 », Franck told us enthusiastically.
We were lucky enough to have original encounters such as silvertip sharks, Guitarfish (otherwise known as the long-snout shovelnose ray) or special dragon sea moths. Although this season was not representative of the usual conditions of diving in the Mergui Archipelago, we still had a great time and are looking forward to the return of better conditions for seasons to come.
Experts say that in an average 30-year period, the ocean would undergo about 4 of each positive and negative phases that each have a duration of about six months. Models also suggest that consecutive positive phases will only occur twice over every 1,000 years. This past season may have brought rare conditions including cold water, poor visibility and strong thermoclines, but we can now expect warm, clear waters for the coming ten years.
Located off the coast of Myanmar, Mergui Archipelago is made of more than 800 islands, for the most part uninhabited, in a perimeter of more than 36,000 square meters. Vastly unexplored and little known by most travellers, this diver’s paradise is only reachable by boat to a select few since 1997.
The Smiling Seahorse is the expert when it comes to diving Myanmar since 2012. Their new liveaboard, launched in November of 2018, can take up to 16 divers to the most unexplored dive sites of South East Asia. The owner, Franck Fogarolo and its team are known for excellent customer service, unmatched cuisine and a fun atmosphere.
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Article Written By Camille Fogarolo
Photo Credit: Franck Fogarolo & Julien Widmer