Invertebrate
Kakaban golden jellyfish
Mastigias cf. papua
The most numerous of four stingless jellyfish species isolated in Kakaban's marine lake, alongside Aurelia, Tripedalia and Cassiopea. Long isolation has left its stinging cells too weak to penetrate human skin. This is a separate population from Palau's endemic Mastigias papua etpisoni, and Indonesian sources apply both Mastigias papua and Mastigias cf. albipunctatus to it, so the name recorded here is provisional.
- Max size
- Bell to roughly 10cm
- Habitat
- Kakaban's landlocked brackish marine lake
Best places to dive with Kakaban golden jellyfish
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Coded conservatively on purpose. The jellyfish largely disappeared from the lake surface in late 2023, prompting a closure of nearly two years; officials attributed the decline to chemicals from swimmers' sunscreen and lotion. Reporting from mid-2025 described mostly juvenile individuals, and reporting from April 2026 described thousands present but concentrated away from the jetty where visitors expect them. Whether you can enter the water at all is unclear — 2025-2026 sources conflict between supervised snorkelling under strict rules and a straight swimming ban. Do not plan a trip around this lake.
Sources & last checked
Checked August 2026
This is a researched draft, not yet human-verified. The seasonality and logistics are drawn from the sources below — confirm specifics (permits, fees, closures) with an operator before you book.
- Berenang bersama ubur-ubur tidak menyengat di Danau Kakaban — ANTARA News
- Menparekraf kunjungi Pulau Kakaban — Pemerintah Kabupaten Berau
- Danau Kakaban Berau, satu dari dua danau ubur-ubur langka di dunia — Good News From Indonesia
Note on the data: Not assessed by the IUCN, so conservation status is recorded as unknown. The lake's population crashed in late 2023 and the lake was closed from 23 December 2023 until early 2025; recovery reporting since is mixed.