Clear Lake, Palau

WorldBlue  In short

Although Jellyfish Lake is the most famous lake with jellyfish in Palau, it is not the only one. In more than 20 marine lakes (small saltwater lakes connected to the sea through limestone fissures) of Palau there is living jellyfish. Five of these lakes have been studied more – the mentioned Jellyfish Lake, Goby Lake, Uet era Ngermeuangel, Uet era Ongael and Clear Lake.

2.1 out of 10 stars 20.8%

GPS coordinates
7.15270 N 134.35923 E
Location, address
Australia and Oceania, Micronesia, Palau, Koror, Rock Islands, Eil Malk (or Mecherchar)
Alternate name
Clearwater Lake
3.9 ha
Dominating species
Mastigias cf. papua salii

Map of the site

Travelers' Map is loading...
If you see this after your page is loaded completely, leafletJS files are missing.

WorldYellow In detail

Testing ground for evolution

Each of the marine lakes of Palau has a specific set of species occasionally trapped in lakes by the receding sea 15 – 10 thousand years ago. Some lakes have steeper banks, some are elongated in an east-west direction, some in a south-north direction. Every such detail leads to different circumstances and consequently – different new species and subspecies of animals.

Some marine lakes of Palau are made even more exotic by the fact that they are meromictic – below the upper layer of marine water there is a layer of "dead", anoxic water separated by a layer of floating microorganisms, including a purple bacteria.

Such unusual monuments of nature serve as excellent “testing ground” for studies of evolution. Thus lately several scientists have made interesting treatises about these lakes. Lucky them (scientists!) – making science in beautiful Palau…

Jellyfish of president Salii

Clear Lake is small (just 3.9 ha) and its maximum length is just some 330 meters, the age of the lake – approximately 12,000 years. Depth reaches 30 meters, purple-sulfur bacteria layer is located in the depth of 15 – 16 meters, below there is an anoxic layer of water without life.

Although the lake is small, here lives endemic subspecies of jellyfish – Mastigias cf. papua salii, named after the third president of Palau Lazarus Salii.

Species composition in Clear Lake is similar to species composition in Jellyfish Lake. Here also lives a predator of jellyfish – sea anemone Entamaea medusivora.

But there is an important difference – while the Jellyfish Lake is elongated in the east-west direction, Clear Lake is stretched in the north-south direction. It seems that this seemingly slight difference has a big influence on the fauna of the lake. The border between the seawater and anoxic water in Clear Lake is more diffuse and oxygen level is falling already at 6 – 10 meters depth.

This is the most likely reason why jellyfish in Clear Lake appears sporadically, while in Jellyfish Lake there always (almost) is a lot of jellyfish.

Jellyfish of Clear Lake also have a daily migration pattern, although less pronounced than in Jellyfish Lake, here jellyfish do not evade shadow.

In order to survive sea anemones also had to elaborate different behavior – besides the jellyfish it consumes mussels as well.


  1. Coral Reef Research Foundation, Marine Lakes Research Accessed 08.02.10.
  2. Jellyfish swarms, tourists, and the Christ-child, Mike N. Dawson, Laura E. Martin, Lolita K. Penland. Hydrobiologia 451: 131-144, 2001.
  3. Five new subspecies of Mastigias (Scyphozoa: Rhizostomeae: Mastiigidae) from marine lakes, Palau, Micronesia, Michael N. Dawson. Journal of Marine Biological Association, U.K. 2005., 85., 679-694. Accessed 08.02.10.

WorldYellow Linked articles

Diving in Blue Holes, Palau
Diving in Blue Holes / , Flickr / CC BY 2.0

Wonders of Palau

Although Palau is small in size, it offers a surprising diversity of interesting monuments. Several of these monuments are true wonders and there are several unresolved mysteries related to Palau.

The lake of acid in Ijen Crater, Indonesia
The lake of acid in Ijen Crater / © CEphoto, Uwe Aranas, Wikimedia Commons

Lakes and streams

There are many factors that can make lakes, sea bays, or rivers unusual. Some lakes have unusual chemical properties and even do not contain water at all – such as lava lakes. Others may have unusual animals living in them or… legends about such animals.

Penguins in Crozet Islands, Possession Island
Penguins in Crozet Islands, Possession Island / , Flickr / CC BY 2.0

Animal colonies

The sight of the gathering of countless penguins or antelopes is very fascinating and intriguing. There are locations in the world where such gatherings are permanent or regular, and: if there is a location with intriguing sights – this is a landmark!

WorldYellow Recommended books

Bucket List Adventures: 10 Incredible Journeys to Experience Before You Die

Author Annette White has made a second career out of writing her bucket list… and then crossing things off of it! One day this owner of a Michelin-recommended restaurant in Northern California decided to live her dream.

Diving & Snorkeling Guide to Palau and Yap 2016

Palau is one of the world’s underwater wonders and Yap is both the most culturally intact isle in the region and a worthy diving and snorkeling mecca in its own right. This guide is new for 2016, with new images, more information on the outer atolls, and updated dive site information.

0 0 votes
Article Rating
Notify of

Inline Feedbacks
View all comments