Depth
Holothuria · Echinoderms (Starfish, Urchins & Brittle Stars)

Black Sea Cucumber

Holothuria forskali

0-40m
Depth Range
Variable
Max Size
Mediterranean
Distribution
0-40m
Depth Range
Variable
Max Size
Reef & Open
Habitat
Carnivore
Diet
Solitary
Social
LC
IUCN Status
Kingdom Animalia
Phylum Echinodermata
Genus Holothuria
Species forskali

Echinoderm

Identification & Biology

  • IdentificationA large, elongated sea cucumber with a smooth, leathery black skin. The body is cylindrical with a flat underside bearing rows of tube feet for locomotion. Scattered white-tipped papillae (small bumps) may be visible on the upper surface.
  • SizeBody length up to 25 cm. Diameter up to 6 cm.
  • Social HabitSolitary or in scattered groups. Slow-moving. Moves across the seabed ingesting sediment. When stressed, can expel sticky white threads (Cuvierian tubules) as a defence mechanism.
  • HabitatRocky reefs, boulder fields, and mixed substrates. Often found on open rocky surfaces and in shallow pools.
  • Depth0 to 100 m. Common in the shallows to about 30 m.
  • Feeds OnOrganic matter, detritus, and microorganisms in the sediment. A deposit feeder that processes large quantities of surface material.
  • DistributionEastern Atlantic from the British Isles to West Africa, and throughout the Mediterranean Sea. Common in Maltese waters.
  • DescriptionHolothuria forskali is one of the most commonly seen sea cucumbers in Malta. Its glossy black body is easy to spot on rocky reefs. If handled or threatened, it can expel a mass of sticky white threads called Cuvierian tubules from its rear end, which entangle and deter predators. These threads are extremely sticky and difficult to remove from dive gloves.

Range

Habitat & Distribution

Found across the Mediterranean, inhabiting reef & open 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

Reef & Open 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.

Black Sea Cucumber species card

Biology

Behaviour & Diet

Feeding Strategy

Deposit feeder that ingests sediment and extracts organic matter using its branching oral tentacles. Processes large quantities of sandy and muddy substrate daily.

Deposit feeder

Reproduction

Sexes are separate, with synchronised spawning events releasing eggs and sperm into the water column. Larvae develop through a planktonic auricularia stage.

Broadcast spawner

Behaviour & Defence

When severely threatened, it can eviscerate its internal organs through the anus, entangling predators in sticky Cuvierian tubules. The expelled organs are regenerated within a few weeks.

Evisceration

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Where to Encounter in Malta

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

5-30m
North Malta

Cirkewwa

Rocky reef with caves, arches and ledges hosting a rich diversity of reef species.

View dive site ›
5-50m
Gozo

Blue Hole

One of the Med's most famous reef dive sites. Rocky walls and archways covered in life.

View dive site ›
18-36m
South Malta

Um El Faroud

The wreck lies on a sandy bottom surrounded by rocky reef -- a diverse habitat attracting reef species.

View dive site ›
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