Pinkfish

• By processing tonnes of sediment a year, sea cucumbers aerate and clean the reef floor and lower its local acidity, a service that favours coral growth.
• Under attack it can expel part of its internal organs through the anus — sticky and sometimes toxic — and regrow them within weeks.
• It is one of the species traded as trepang or bêche-de-mer, and the enormous Asian demand has depleted its populations across much of the Indo-Pacific.
• It swallows sand and expels it stripped of organic matter. That work, multiplied by millions of individuals, is a real ecosystem service: sea cucumbers turn over and oxygenate the reef sediment and locally counteract acidification, because in digesting the carbonate they release alkalinity.
• It defends itself by evisceration: it expels part of its internal organs through the cloaca, leaving them behind as a distraction, and regenerates them within weeks.
• And sometimes it expels Cuvierian tubules, sticky filaments that entangle the aggressor.
• Its name, edulis, alludes to its use: it is eaten dried as bêche-de-mer or trepang, above all on the Chinese market.
• That demand has depleted sea cucumber populations across the whole Indo-Pacific, and several species of the genus are threatened; many countries have closed or restricted the fishery.
• It frequently hosts an awkward lodger: the pearlfish, which lives inside its cloaca.

Skeleton type

Invertebrate - endoskeleton of calcareous plates (echinoderm)

Habitat and environment

Sandy and rubble reef bottoms of the Indo-Pacific, from 0 to 30 m

Sources consulted: Wikipedia (es): Holothuria edulis