+680-4881117 palauoceandivers@gmail.com
English / Chinese

Jellyfish Lake

Jellyfish Lake (Palauan name : Ongeim'l Tketau)  is the most know of Palau's marine lakes. Vistiors from around the world visit the lake to see its spectacular population of golden jellyfish (Mastigias papua estisoni). Jellyfish lake is the only lake open to visitors, as all the other marine lakes are closed to visitors. 

Jellyfish Lake is typical of the more isolated type of marine lake, The perimeter of the lake is surrounded by mangrove trees covered by sponges, algae gastropods and sea squirts typical of mangrove habitats. There are no corals found in this lake. Rainfall has dilluted the surface water salinity to approximately 75% the strength of full seawater. At deeper depths, the lake water has a higher salinity than that of the surface. 


The lake reaches 32 meters (100 feet) at its deepest point. However, plant and animal life are restricted to the top 15 meters(48 feet) of the lake. Below this depth, the water lacks oxygen and instead, contains high concentration of the toxic compound hydrogen sulfide. For this reason all marine organisms that requires oxygen to live are restricted to the top 15 meters (48 feet) of the lake. Bacteria inhabit this dark, poisonous layer. The hazards presented by this compound are responsible in part of for the ban on scuba diving in the lake.

 The number of medusae varies considerably through time. When the lake was very warm during the La Nina events both in 1998-1999 and 2016-2018, the medusa stage of the golden jellyfish was completely absent. The polyp stage, however, survived this warm period replenishing the lake with medusae when the lake cooled in January 2000. The recent re-open of Jellyfish Lake to visitors was on October,2018. In February 2019, the number of Jellyfish in the lake has reached to over 1 million again. 


Hot In Town

Special Expedition