Bohadschia argus

The leopard sea cucumber, also called the leopardfish or tigerfish, is a species of sea cucumber from the family Holothuriidae. It lives in the tropical Western Indo-Pacific region.

Description

Like most sea cucumbers, Bohadschia argus has a roughly cylindrical body. It typically reaches about 36 cm (14 in) in length and weighs between 1.8 and 2.2 kg (4.0 to 4.9 lb), with a maximum recorded length of 60 cm (24 in).

Its tough outer body wall is about 10 mm (0.39 in) thick and feels firm and leathery. The upper side is greyish-brown and covered with many yellow eyespots, which give the animal its common name. The underside is usually paler, though some individuals are uniformly brown.

Several rows of tube feet on the underside help it move. Around the mouth at the front end is a ring of black, paddle-shaped feeding tentacles with white fringes.

At the rear end, near the anus, are Cuvierian tubules. When disturbed or handled, the sea cucumber ejects these sticky threads, which contain toxins that deter predators and can irritate human skin. Bohadschia argus can apparently hybridize with Bohadschia vitiensis.

Distribution and habitat

This species lives in shallow tropical waters across the eastern Indian Ocean and western Pacific. It is common on exposed, sandy areas of the seabed around coral reefs, usually at depths of 2 to 10 m (6.6 to 32.8 ft).

Ecology and behavior

As a detritivore, Bohadschia argus sweeps sand grains and detritus into its mouth with its sticky tentacles as it moves across the seabed. It gets some nourishment from the biofilm coating the grains.

Symbiotic relationships

Pearlfish—specifically Carapus mourlani (star pearlfish) and Encheliophis boraborensis (pinhead pearlfish)—sometimes live inside the sea cucumber’s coelomic cavity, usually entering head-first through the anus. In a study in the Banda Islands, 15 star pearlfish were found inside a single Bohadschia argus. Carapus mourlani has a mutualistic relationship with the sea cucumber and will aggressively defend it from the parasitic Encheliophis boraborensis, sometimes fighting to the death. The emperor shrimp (Zenopontonia rex) is also often associated with Bohadschia argus and may help keep it free of ectoparasites.

A new compound called Arguside A, a triterpene glycoside, has been extracted from the sea cucumber’s tissues. This substance appears to be cytotoxic against several types of human tumor cells.