Tubular Sea Cucumber

Overview

The Tubular Sea Cucumber (Holothuria tubulosa) is a common echinoderm frequently encountered in the Mediterranean Sea and parts of the Eastern Atlantic. It is a bottom-dwelling species known for its cylindrical, leathery body and its role in processing marine sediments.

Distribution & habitat

This species is widely distributed across the Mediterranean and the Eastern Atlantic. It inhabits a variety of seafloors, including sandy, rocky, and detrital bottoms, and is often found within seagrass meadows. While younger individuals typically prefer the shelter of seagrass beds, older specimens are more commonly observed on open sandy substrates.

Appearance

Reaching lengths of up to 45 cm, this sea cucumber has a tough, cylindrical body that is typically brown, sometimes with reddish or purplish hues. Its surface is covered in numerous dark, conical, thorn-like projections called papillae. The underside is flattened and features three longitudinal rows of tube feet used for movement and attachment. It often appears greyish due to a protective layer of mucus that can trap sand and debris.

Feeding

As a deposit feeder, it plays an important role in the ecosystem by ingesting large quantities of sand and mud. It extracts organic matter, detritus, and plankton from these sediments as they pass through its digestive system.

Reproduction

Holothuria tubulosa is dioecious, meaning individuals are either male or female, though they look identical externally. Reproduction typically occurs during the summer months, often peaking in August. During mass spawning events, individuals release their gametes directly into the water column, where fertilization takes place.