Depth
Velella · Cnidarians (Jellyfish, Anemones & Corals)

By-the-wind-sailor

Velella

0-40m
Depth Range
Variable
Max Size
Mediterranean
Distribution
0-40m
Depth Range
Variable
Max Size
Open Water
Habitat
Carnivore
Diet
Solitary
Social
LC
IUCN Status
Kingdom Animalia
Phylum Cnidaria
Genus Velella
Species

Cnidarian

Identification & Biology

  • IdentificationNot a true jellyfish but a colonial hydrozoan. A flat, oval, blue disc (up to 10 cm) with a rigid, triangular sail rising from the top. The sail catches the wind, propelling the colony across the ocean surface. Short, blue tentacles hang below.
  • SizeDisc diameter up to 10 cm. Sail height up to 4 cm.
  • Social HabitColonial (each individual is a colony of specialised polyps). Found in vast flotillas of thousands on the open ocean surface, driven by wind and currents.
  • HabitatOpen ocean surface (neustonic). Wind-driven, often washing ashore in large numbers during onshore gales.
  • DepthSurface only. A strictly surface-dwelling organism.
  • Feeds OnSmall plankton, fish eggs, and larvae captured by the short blue tentacles hanging below the float.
  • DistributionWorldwide in warm and temperate oceans. Seasonally present in the Mediterranean, including Maltese waters. Mass strandings occur on beaches after strong westerly winds.
  • DescriptionVelella velella is a remarkable organism that spends its entire life sailing the ocean surface. Each individual is actually a colony of specialised polyps working together. The angled sail causes the colony to travel at an angle to the wind, which distributes the population across wide stretches of ocean. When onshore winds blow in Malta, thousands can wash up on beaches, creating striking blue lines along the waterline. The sting is harmless to humans.

Range

Habitat & Distribution

Found across the Mediterranean, inhabiting open water environments. Active from the surface down to 40m depth.

Where Malta divers have spotted this species

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Sightings are logged by divers using our What Did You See? dive-log tool. View the full live sightings map.

Detail

Preferred Environment

Open Water habitats, typically at depths of 0-40m. Most commonly encountered by divers at the shallower end of its range.

Encounter Tips

Best approached slowly and calmly. Avoid casting shadows directly over the animal. Neutral buoyancy and patience increase encounter success significantly.

Biology

Behaviour & Diet

Feeding Strategy

A surface-dwelling colonial hydrozoan that feeds on zooplankton, fish eggs and small crustaceans captured by trailing dactylozooids armed with nematocysts beneath the float.

Surface predator

Reproduction

Reproduces asexually by budding small medusae from the colony. These free-swimming medusae then reproduce sexually, releasing eggs and sperm into open water.

Budding

Behaviour & Defence

A chitinous sail set diagonally across the float carries the colony away from threats using wind power. Its blue pigmentation may provide UV protection and deter visual predators.

Wind dispersal

Dive with diveshack

Where to Encounter in Malta

The following dive sites offer strong habitat match for Velella. All are accessible on a guided dive with diveshack.

0-30m
Comino

Blue Lagoon

Open water around Comino is a known passage for pelagic species, especially in summer.

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5-30m
North Malta

Cirkewwa

The channel crossing at Cirkewwa draws pelagic species following currents from the open sea.

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18-36m
South Malta

Um El Faroud

The open reef beyond the wreck is visited by pelagic and semi-pelagic species on feeding runs.

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IUCN Red List Least Concern

Conservation Status

This species is assessed as Least Concern on the IUCN Red List. Mediterranean populations face ongoing pressure from fishing activity, habitat degradation, and climate-driven changes to prey availability.

Source: iNaturalist Guide #888
by Lesley Clements (CC BY-SA)
diveshack Mediterranean Marine Life guide