Holothuria · Echinoderms (Starfish, Urchins & Brittle Stars)

Cotton-spinner

Holothuria tubulosa

0-40m

Depth Range

Variable

Max Size

Mediterranean

Distribution

Echinoderm

Identification & Biology

IdentificationA large, elongated sea cucumber with a cylindrical brown body covered in darker brown to black papillae (small bumps) arranged in rough rows. The underside is lighter with three rows of tube feet. Named for its ability to expel long, white sticky threads.
SizeBody length up to 30 cm. Diameter up to 8 cm. One of the most common sea cucumbers in the Mediterranean.
Social HabitSolitary or in loose groups. Slow-moving. Crawls across open seabed ingesting surface sediment. Expels white Cuvierian tubules when stressed.
HabitatSeagrass meadows, sandy bottoms with some rock, and mixed substrates. Often found on Posidonia meadow edges.
Depth0 to 100 m. Common between 2 and 40 m.
Feeds OnDetritus, organic matter, and microorganisms in the surface sediment. Ingests and processes large volumes of sediment.
DistributionEastern Atlantic and throughout the Mediterranean Sea. Very common in Maltese waters.
DescriptionHolothuria tubulosa is the most commonly encountered sea cucumber in Malta. It plays an important ecological role as a sediment recycler, processing organic matter and keeping the seabed clean. The white sticky threads (Cuvierian tubules) it can expel as a defence are notorious for tangling in dive gear and being very difficult to remove.

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.

Biology

Behaviour & Diet

Feeding Strategy

Deposit feeder that uses sticky, branching oral tentacles to collect organic matter and detritus from the seabed. Processes significant volumes of sediment, playing an important role in nutrient recycling.

Deposit feeder

Reproduction

Sexes are separate, with eggs and sperm released into the water during summer spawning events. Larvae develop through a planktonic stage before settling on soft substrates.

Broadcast spawner

Behaviour & Defence

Expels thick, white, sticky Cuvierian tubules from its anus when threatened, entangling and irritating predators. These specialised defensive organs regenerate after use.

Sticky tubules

Dive with diveshack

Where to Encounter in Malta

The following dive sites offer strong habitat match for Holothuria tubulosa. 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.

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5-50m

Gozo

Blue Hole

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

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18-36m

South Malta

Um El Faroud

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

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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