Spotted Jelly

In some lakes on Palau island (part of Micronesia in the Western Pacific) populations declined dramatically in 1998. Scientists hypothesize that the jellies disappeared because of changes in the lake water due to the very severe El Niño of 1997-98. Elevated temperature and salinity created an unhealthy environment for the jellies. By the year 2000, jelly numbers were rebounding.(Monterey Bay Aquarium, 2008)

South Pacific Ocean, Hawaii, Puerto Rico.(Monterey Bay Aquarium, 2008)

Some larger spotted jellies may host small fishes. The fishes use the inside of the jelly’s bell as protection from larger predators until they reach maturity.(Monterey Bay Aquarium, 2008)

Coastal Waters. Known as a “lagoon jelly” because it lives in bays, harbors and lagoons in the South Pacific.(Monterey Bay Aquarium, 2008)

Bell:Spotted jellies have rounded bells.(Monterey Bay Aquarium, 2008)

Arms: strange clumps of oral arms bear clublike appendages that hang down below. Instead of a single mouth, they have many small mouth openings on their oral-arms, which capture small zooplankton.(Monterey Bay Aquarium, 2008)

Color: each jelly grows a crop of algae, which gives them a greenish-brown color. They harvest some of their food directly from the algae.(Monterey Bay Aquarium, 2008)

Can grow to 2 feet (61 cm) in diameter.(Monterey Bay Aquarium, 2008)

Diet:zooplankton, food produced by zooxanthellae (symbiotic algae).(Monterey Bay Aquarium, 2008)

Spotted jellies swim in large swarms to stay in the direct rays of the sun. Sunlight fuels the growth of the symbiotic algae the jellies thrive on. At night, spotted jellies descend to deeper waters, to an anoxic (oxygen-deficient) layer that's high in concentrations of hydrogen sulfide. There, the jellies absorb ammonium, which fertilizes the algae.(Monterey Bay Aquarium, 2008)

Width to 10 cm. Conspicuous. Eight thick mouth-arms with long terminal clubs, which may detach. Bell transparent when young, later translucent dark bluish-green or pale brown, with scattered pale patches. Swims incessantly and often swarms. Habitat: coastal waters. Distribution: W Indian Ocean, Red Sea to W Pacific Ocean, N Australia, also SW Atlantic (Richmond, 1997).