Swim with stingless jellyfish in Mariona Lake, Sulawesi

Mariona Lake in Togean Islands, Central Sulawesi, is an ancient doline filled with seawater over the centuries. Sheltered in this protected environment with no predators, two species of jellyfish have lost their only weapon: the sting. This natural wonder, as most sources claim, can only be found in seven locations around the world. Three of them happen to be in Indonesia. Mariona Lake is probably the most easily accessible of those and, combined with the overall beauty of the Togeans, it makes an excellent choice for a tourist. While enjoying rest and seclusion on your own little uninhabited island, snorkeling and exploring the coral gardens, why not take a detour and swim in the swirling clouds of stingless jellyfish?

A whole galaxy of jellyfish

Isolation from predators has not only caused the plankton-eating jellyfish to evolve out of their venomous defense strategy, but also allowed them to breed uncontrollably. There's a lot of them; like, tremendous, uncountable, overwhelming numbers. When you put on your mask and jump into the lake, it seems there are more jellyfish than water. Lightweight and radiant, those live umbrellas swirl and dance all around you, like a galaxy of little stars. The beauty of this spectacle is unforgettable. The creatures are safe to play with: technically, they still have the venom, but their sting cells have atrophied, rendering them unable to penetrate human skin. But be careful - they are very fragile.

Not only jellyfish

Lake Mariona had apparently formed millennia ago as a sinkhole in the coral bedrock of the islet. Over time, mildly acidic rainwater and the tidal activity of the ocean had eroded the narrow barrier separating it from the sea, creating tiny underwater tunnels. Those wouldn't be broad enough to let in larger animals, but some small coral fish, various plankton and benthos species, and of course the jellyfish, had successfully infiltrated. The unusual environment has led to mutations: aside from the stingless jellyfish, the sponges and algae covering the walls of the doline are quite different from their open-water siblings. With a snorkel and a fair bit of time, one could even rin his own private research.

Practicalities

Unless you have your own boat, the only practical way to get to Mariona Lake is to hire one. This would be rather expensive to do independently, but any resort in Togean Islands can arrange a visit, splitting the cost among the tourists. Such boat tours may include other islands, and will definitely stop on a nearby beach for an hour or two of rest. Select the option that suits you, or negotiate it. At the time of research, there was no entrance fee to this natural wonder, and no payment was required to actually take a swim with the stingless jellyfish. This is likely to change soon, according to the golden rule of tourist attractions: if money can be shaken out of foreign visitors, it will be. Snorkels and life vests may soon be available on the spot, too, but for now make sure your boat captain has brought them along. There's no way to reach the lake without staying in the Togeans since the island is pretty far from the main body of Sulawesi.