Black Sea Jellyfish
(Maeotias inexspectata)

Description: This species of sea jelly is relatively small (maximum diameter 5.5 cm) and has particularly dense long tentacles (up to 600) lining the edge of the milky-white bell. The stomach, which is set on the underside of the bell and is relatively large, appears as a frilly "X" across the bottom. Also set on the underside of the bell are 4 distinct radial canals that each hold a curtain-like gonad. Unlike most of our common local jellies, the Black Sea jellyfish is not an active swimmer and only occasionally beats its bell. It often rests on the bottom where it feeds on bottom dwelling organisms, but it is also found in the water column and near the surface.

Habitat: The Black Sea jellyfish is typically abundant from late spring through summer in the brackish waters of bays, either near the bottom or in the water column.

Origin: Black Sea.

Invaded Areas: Brackish waters in Francisco Bay; Chesapeake Bay.

Concerns: This species can rapidly reproduce to form dense swarms of jellies. In the early 1990s, an introduction into the San Francisco Bay area may have been due to fouled ships. A bloom observed in the Petaluma river in 1993 attracted public interest. Dense populations of this jelly can alter estuarine food webs. The prey of this jelly includes small adult crustaceans and larvae, so local populations of crabs and their relatives could be diminished.