At a glance
Essentials
- Size
- 25-40 cm in diameter The range may vary with age, sex and population.
- Distribution
- Northeast Atlantic, Baltic Sea, northeastern U.S. and Argentina
- Habitat
- Coastal waters, estuaries, and bays
- Activity
- Drifts with currents
- Diet
- Zooplankton, copepods, fish eggs, and small invertebrates
- Conservation
- Not evaluated
Observation guide
What to look for
- 01
Translucent bell of 25 to 40 cm in diameter with four gonads in the shape of a horseshoe visible on the upper surface.
- 02
Bell edge with hundreds of filamentous and thin tentacles, and four thicker central oral arms.
- 03
Tetramerous symmetry and bell edge divided into eight shallow lobes where the rhopalia are situated.
Lighting, age and viewing angle can hide features. If identification affects consumption, handling or conservation, consult specialist sources.
Ecology
Description and characteristics
This jellyfish exhibits tetramerous symmetry and a nearly circular bell that, in adult individuals, reaches a diameter of between 25 and 40 cm. The body is predominantly translucent, with an ectoderm that may show bluish or pinkish tones and a white and transparent endoderm. A key diagnostic feature is the presence of four gonads in the shape of a horseshoe, clearly visible through the upper surface of the bell. The edge of the bell is surrounded by hundreds of long, thin, stinging tentacles, while in the center extend four thicker oral arms, which are more evident in mature specimens. The edge of the bell usually presents eight shallow lobes, where the rhopalia, sensory structures that orient the animal's movement, are located.
The species moves by contracting the bell via the coronal muscle, a process that allows it limited movement, so it frequently drifts with marine currents. Being unable to effectively oppose the flow of water, it tends to concentrate in coastal waters, estuaries, and bays, where food availability is greater. Although it can live in open waters, it prefers shallow and coastal zones, where it is often dragged in large concentrations by currents.