Holothuria grisea
A coastal sea cucumber harvested in Brazil, not currently overfished.
The gray sea cucumber, *Holothuria grisea*, is a medium-sized coastal species that lives in the shallow, warm waters of the Atlantic. Its range stretches from Florida down to southern Brazil and across to West Africa. Despite its common name, it is not typically gray; its color varies widely, from red to yellowish, often marked with brown patches. People harvest it for food, both locally and for export, with most of that fishing happening in Brazil. The species is not currently overfished and is not considered endangered or threatened.
In terms of classification, Emil Selenka first described this sea cucumber in 1867. The genus name *Holothuria* comes from Latin for “water polyp.” It belongs to the phylum Echinodermata—Greek for “spiny skin”—which also includes sea stars and sea urchins. Within that phylum, it sits in the class Holothuroidea, the sea cucumbers. It is placed in the subgenus *Halodeima* and is also known by the synonyms *Halodeima grisea* and *Ludwigothuria grisea*.
Like all echinoderms, the gray sea cucumber has pentaradial symmetry. Its body is mostly cylindrical, with a flattened underside. Adults can reach up to 30 cm in length, but they average around 14 cm. The base color ranges from red to orange to yellow, with brown mottling that helps camouflage them among the reefs. On the back, the papillae are white near the base and turn yellow toward the tips. The tentacles and the tube feet on the underside are also yellow. Tube feet, which echinoderms use for movement, work through hydraulic pressure. Adults have six rows of papillae on their dorsal surface, while juveniles have only four. Each papilla holds 5 to 10 tube feet, and the mouth is ringed by 20 to 25 branched tentacles. The mouth faces downward because these animals are bottom feeders. Their bodies are reinforced by ossicles—calcified structures that form a kind of internal skeleton—and by internal plates. *H. grisea* is an osmoconformer, meaning its internal salt concentration matches that of the surrounding water.
Reproduction in this species is gonochoristic, with separate males and females. Fertilization happens externally through broadcast spawning: eggs and sperm are released into the water column and must find each other. Spawning is seasonal, triggered by changes in light, temperature, salinity, moon phase, food availability, and other factors.
Quick Facts
- Genus
- Holothuria
- Species
- grisea
Facts from the source article.
Lore & Background
Holothuria grisea was first described by Emil Selenka in 1867. Its genus name Holothuria is derived from Latin meaning water polyp, and it belongs to the phylum Echinodermata (spiny skin in Greek), which also includes sea stars and urchins. It is classified under the sub-genus Halodeima and is synonymous with Halodeima grisea and Ludwigothuria grisea. The species exhibits pentaradial symmetry and is mostly cylindrical with a flattened ventral side. Coloration is variable and generally not gray; base colors range from red to orange to yellow with brown mottling, serving as camouflage in reefs. Dorsal papillae are white transitioning to yellow at the tips, and the tentacles and tube feet are yellow. Adults have six rows of papillae on the dorsal surface, while juveniles have only four. The mouth is surrounded by 20–25 branched tentacles and faces downward as they are bottom feeders. They are covered in ossicles, calcified structures that form a skeleton, and have internal plates. H. grisea is an osmoconformer, meaning its internal salt content matches the surrounding water.
Reader's Guide
Holothuria grisea plays an important ecological role as a deposit feeder, sifting through sediment to consume organic waste, algae, small invertebrates, and detritus. Its feeding and burrowing behavior results in bioturbation, releasing inorganic phosphorus and nitrogen that provide essential nutrients to benthic organisms. The species also helps buffer the environment from ocean acidification and serves as a host for parasites and symbiotic species, increasing biodiversity. Its eggs and larvae are a food source for juvenile fish and other small organisms, while adults are prey for starfish, crabs, fish, and sea turtles, transferring energy up the food web. Economically, the gray sea cucumber is heavily fished in Northern Brazil, with the majority exported to Asia. Although not currently overfished, studies show that 66% of harvested individuals were immature, meaning they had not reproduced before harvest. The fishery is unregulated with no reporting or documentation, which could lead to future overexploitation and declines in sediment quality, water quality, and biodiversity. The IUCN lists it as Least Concern, but the unregulated fishery and lack of data pose potential risks.
Did You Know?
- Spawning occurs in June and July during the rainy season, timed with high phytoplankton growth.
- 66% of harvested individuals in Brazil were immature, having not yet reproduced.
More in Sea Cucumbers and Brittle Stars, Part 2 1-24
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