Jellyfish Lake

After leaving Chuuk, Carl and I headed to Palau! I was here for work in September-October, and I was more than happy to be back. Palau is one of the more developed island nations in the Pacific, and it features beautiful, pristine natural habitats for diving. After two weeks of quirky living conditions in Chuuk, it's been nice to be in a more Westernized area. Carl and I are spending our week here diving on gorgeous, densely-populated coral reefs. We're seeing hundreds of species each dive, along with sharks and turtles and manta rays and fish. The natural environment here is truly unparalleled - and I'm not just talking it up. I absolutely love diving in Palau. 

One of the very famous sites in Palau is Jellyfish Lake, a marine lake in the Rock Islands. It's populated by a subspecies of endemic jellyfish that have a very weak sting. Over centuries of isolation in the lake, the jellies have not needed to defend themselves or catch food, so their cnidocytes have become so weak that a human can't even feel the sting. To feed themselves, the jellyfish have photosynthetic symbionts, much like corals, so their nutrition comes from sunlight. Most jellies are predators, but the subspecies in Jellyfish Lake migrates around the lake throughout the day, following the sun. It's like the cnidarian equivalent of the reformed sharks in Finding Nemo - a tribe of former meat-eaters living in harmony in paradise. 

Our visit began with a boat ride to the island, called Mecherchar, where the lake sits. We parked at the dock and carried our gear on a steep stone staircase over a ridge, first up, then down. From the surface, it looked like any other lake - still water nestled among trees, with a handful of snorkelers splashing at the surface. We donned our masks and fins, eased ourselves into the water, and swam to the center. I put my face beneath the surface and was instantly in another world. The jellies, barely visible from above the surface of the water, were everywhere. Thousands of them, millions - we were told that the lake's population was about 2 million individuals, and usually, it's closer to 10 million. All of them drifted along slowly, contracting their bells absentmindedly as their tentacles trailed behind. They were a deep peach color, almost brown. 

Our guide told us that there are actually five marine lakes with endemic jellyfish in Palau. Four are closed to the public, and each one has a unique subspecies of jelly that is found nowhere else in the world. All of the subspecies are closely related to a species that is common in the Rock Island bays of Palau, so the prevailing theory is that birds carried dried polyps on their feathers from the bays to the lakes, and the isolated jelly populations diverged over time. 

I am immensely grateful that we got to experience Jellyfish Lake. It is a fragile, unique environment that was a privilege to see.