Learn & Explore/Species/Introduced & Invasive/Upside-Down Jellyfish

Upside-Down Jellyfish

Category: Invasive

A shallow-water jellyfish known to take over marine and loko iʻa (fishpond) environments.

Upside-Down Jellyfish (Cassiopea andromeda)​

  • Yellow with white and pale spots 2

  • Brown frilly tentacles 2

  • Can grow up to 30 centimeters in diameter 3

  • Often mistaken for sea anemones 1

Upside Down Jellyfish 19
Photo: DAR

Habitat

  • Lies upside down on sandy bottoms 2

  • Found in calm, shallow water such as lagoons and intertidal flats 2

Upside Down Jellyfish 27
Photo: DAR

Impacts & Concern

  • Have a mild sting 1

  • Ecological impacts have not been studied 1

Upside Down Jellyfish 4
Photo: DAR

Introduction

  • Came from the Philippines to Pearl Harbor between 1941 and 1945 2

  • Spread by hull fouling or in the ballast water of ships 2

Distribution in Hawai‘i

  • Kauaʻi: Not documented

  • O‘ahu: Kāne‘ohe Bay, Ala Wai Canal, Honolulu Harbor

  • Molokaʻi: Kaunakakai

  • Lānaʻi: Not documented

  • Maui: Not documented

  • Hawaiʻi Island: Waikoloa fish ponds

References and Further Reading

  1. Eldredge, L. G., & Smith, C. M. (2001). A guidebook of introduced marine species in Hawai’i. Honolulu: Bishop Museum and the Univ. of Hawai’i

  2. Eyes of the Reef (EOR). (2015). Alien invasive invertebrates- Upside down jellyfish. Eyes of the Reef Hawaiʻi. https://eorhawaii.org/education/marine-invasive-species/invertebrates/

  3. Bishop Museum. (2001). Cassiopea andromeda. Introduced marine species of Hawai’i Guidebook. Eyes of the Reef resource.

Other Introduced & Invasive

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Marine

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Freshwater

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Brackish

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Seaweed/Algae