Barrel Jellyfish

• As it has no tentacles, its sting is mild and often barely noticed, which sets it apart from other Mediterranean jellyfish that sting far more sharply.
• Juvenile horse mackerel and other fish often shelter beneath its bell, making use of the jellyfish's protection while they grow.
• In Asia it is eaten dried and salted, and commercial fishing for it has begun to be trialled in the Mediterranean too.
• It has no marginal tentacles. Instead it carries eight fused oral arms riddled with thousands of tiny mouths through which it filters plankton, a design entirely different from that of most jellyfish.
• It is among the largest in the Mediterranean: the bell reaches 90 cm and it can weigh more than ten kilos.
• Its sting is mild for people, so its blooms are more of a nuisance to fishing and tourism than to swimmers.
• Its use is being investigated: its collagen and mucins have biotechnological applications, and related jellyfish are eaten in Asia.
• Juvenile horse mackerel and other fish often shelter beneath its bell, using it as a mobile hiding place.

Skeleton type

Invertebrate - no skeleton (gelatinous cnidarian)

Habitat and environment

Coastal waters and brackish lagoons of the Mediterranean and the eastern Atlantic

Sources consulted: Macri (1778) · Leone et al. (2015), Marine Drugs · CIESM · ScienceDirect (Hughes 1989) · Science Advances, How colonial animals evolve · Wikipedia, Zooid

Best time: Summer and autumn, when it comes close to the Mediterranean shore